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MIDDLE EAST JOURNAL OF ANESTHESIOLOGY
Department of Anesthesiology
American University of Beirut Medical Center
P.O. Box 11-0236. Beirut 1107-2020, Lebanon
Editorial Executive Board
Editor-In-Chief:
Ghassan Kanazi
Executive Editors
Fouad Salim Haddad
[email protected]
Maurice A. Baroody
Consultant Editors
Assem Abdel-Razik
(Egypt)
Bassam Barzangi
(Iraq)
Izdiyad Bedran
(Jordan)
Chakib Ayoub
Marie Aouad
Sahar Siddik-Sayyid
Dhafir Al-Khudhairi
(Saudi Arabia)
Mohammad Seraj
(Saudi Arabia)
Managing Editor
Mohamad El-Khatib
[email protected]
Abdul-Hamid Samarkandi
(Saudi Arabia)
Founding Editor
Bernard Brandstater
Mohamad Takrouri
(Saudi Arabia)
(Emeritus Editor-In-Chief) Anis Baraka
Bourhan E. Abed
(Syria)
Honorary Editors
Nicholas Greene
Musa Muallem
Mohamed Salah Ben Ammar
(Tunis)
Webmaster
Rabi Moukalled
Ramiz M. Salem
(USA)
Secretary
Alice Demirdjian
[email protected]
Elizabeth A.M. Frost
(USA)
Editors
The Middle East Journal of Anesthesiology is a
publication of the Department of Anesthesiology of
the American University of Beirut, founded in 1966 by
Dr. Bernard Brandstater who coined its famous motto:
“For some must watch, while some must sleep”
(Hamlet-Act. III, Sc. ii).
and gave it the symbol of the poppy flower (Papaver
somniferum), it being the first cultivated flower in
the Middle East which has given unique service to
the suffering humanity for thousands of years. The
Journal’s cover design depicts The Lebanese Cedar
Tree, with’s Lebanon unique geographical location
between East and West. Graphic designer Rabi
Moukalled
The Journal is published three times a year (February,
June and October) The volume consists of a two year
indexed six issues. The Journal has also an electronic
issue accessed at www.aub.edu.lb/meja
The Journal is indexed in the Index Medicus and
MEDLARS SYSTEM.
E-mail: [email protected]
Fax: +961 - (0)1-754249
All accepted articles will be subject to a US $ 100.00
(net) fee that should be paid prior to publishing the
accepted manuscript
Please send dues via:
WESTERN UNION
To Mrs. Alice Artin Demirjian
Secretary, Middle East Journal of Anesthesiology
OR TO
Credit Libanaise SAL
AG: Gefinor.Ras.Beyrouth
Swift: CLIBLBBX
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Middle East Journal of Anesthesiology
Acc. No. 017.001.190 0005320 00 2
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- Transfer No. and date (WESTERN UNION)
- Receipt of transfer to (Credit Libanaise SAL)
Personal checks, credit cards and cash, are not
acceptable
“For some must watch, while some must sleep”
(Hamlet-Act. III, Sc. ii
SYMPOSIUM ANNOUNCEMENT
28th Annual Symposium
Clinical Update in Anesthesiology, Surgery and Perioperative Medicine
January 17-22, 2010
Paradise Island, Bahamas
BROCHURE, ABSTRACT, POSTER AND PAPERS INFORMATION:
(Deadline – October 16, 2009)
Helen Philips
Mount Sinai Medical Center
1 Gustave L. Levy Place
Box 1010, Dept. of Anesthesiology
New York, NY 10029-6574
Phone: 212 – 241 – 7467
Fax: 212 – 426 – 2009
Email: [email protected]
133
134
Middle East Journal of Anesthesiology
Vol. 20, No. 2, June 2009
CONTENTS
In Memorium... Dr. Carlos Parsloe. ........................................................................... Anis Baraka
139
editorial
Preoxygenation Of The Morbidly Obese With Obstructive Sleep Apnea
.............................................................................................................................. Anis Baraka
141
review articles
Anesthetic Care Of The Patient With Obstructive Sleep Apnea
...... Amir Baluch, Sunil Mahbubani, Fahad Al-Fadhli, Alan Kaye and Elizabeth A.M. Frost
143
Anesthesia And Cardiopulmonary Bypass For Congenital Heart Surgery
....................................................................................................................... Chawki F elZein
153
Preventing Paralytic Ileus: Can The Anesthesiologist Help
................................................................................................................ Elizabeth A.M. Frost
159
Current Perioperative Management Of The Patient With HIV
...................................................................... Amir Baluch, Hiamine Maass, Cynthia Rivera,
Abhinav Gautam, Alan Kaye and Elizabeth A.M. Frost
167
A Proposed Classification Of Simulators
........................................................ Leonard M Pott, Arne O Budde and W Bosseau Murray
179
Modern Strategies For The Anesthetic Management Of The Paitent With Diabetes
.................................... Anhinav Gautam, Amir Baluch, Alan Kaye and Elizabeth A.M. Frost
187
scientific articles
The Impact Of Intraoperative Transesophageal Echocardiography On Decision-Making
During Cardiac Surgery
........................................................................... S Mahdy, BO Brien, D Buggy and M Griffin
199
Effects Of Sevoflurane On Postoperative Liver Functions In Morbidly Obese As Compared
To The Non-Obese Patients
.............................................. Subhi M Al-Ghanem, Islam M Massad, Bassam Al-Barazangi,
Mahmoud Al-Mustafa, Fayez S Daoud and Hamdi Abu-Ali
207
Patient Survey Of Continuous Interscalene Analgesia At Home After Shoulder Surgery
......................................................... Elie J Chidiac, Roland Kaddoum and Steve A Peterson
213
Evaluation Of A Blood Conservation Strategy In The Intensive Care Unit: A Prospective,
Randomised Study
............................. Saad Mahdy, Ehtesham I Khan, M Attia, BP O’Brien and Patrick Seigne
135
219
M.E.J. ANESTH 20 (2), 2009
Intravenous Dexmedetomidine Prolongs Bupivacaine Spinal Analgesia
.............................................. Mahmoud M Al-Mustafa, Izdiad Z Badran, Hamdi M Abu-Ali,
Bassam A Al-Barazangi, Islam M Massad and Subhi M Al-Ghanem
Attenuation Of Hemodynamic Responses Following Laryngoscopy And Tracheal Intubation
- Comparative assessment of Clonidine and Gabapentin Premedication
.................... Seyed Mojtaba. Marashi, Mohammad Hossein. Ghafari and Alireza Saliminia
225
233
Pediatric Cancer Pain Management At A Regional Cancer Center: Implementation Of Who
Analgesic Ladder
............................................................... Seema Mishra, Sushma Bhatnagar, Manisha Singh,
Deepak Gupta, Roopesh Jain, Himanshu Chauhan
and Gaurav Nirwani Goyal
239
The Prophylactic Effect Of Rectal Acetaminophen On Postoperative Pain And Opioid
Requirements After Adenotonsillectomy In Children
....................................................... Gholam Ali Dashti, Shahram Amini and Elham Zanguee
245
Pregnancy At Term Does Not Alter The Responses To A Mechanical And An Electrical
Stimulus After Skin Emla Application
.................................................................................... Amalia Katafigioti, Anteia Paraskeva,
Georgios Petropoulos, Ionna Siafaka and Argyro Fassoulaki
251
Robotic Laparoscopy Radical Cystectomy: Inhalational vs Total Intravenous Analgesia - A
Pilot Study
...................................................................... Mohamed M Atallah and Mahmoud M Othman
257
The Effect Of Nitroglycerine As An Adjuvant To Lidocaine In Intravenous Regional Analgesia
................................................................................. Rahman Abbasivash, Ebrahim Hassani,
Mir Moussa Aghdashi and Mohammad Shirvani
265
Evaluation Of The Touniquet Leak During Forearm Intravenous Regional Analgesia
- Manual vs Automatic pump injection ...................................................................................................... Roshdi Roshdi Al-Metwalli
271
Time To Extubation In Infants Undergoing Pyloromyotomy
- Isoflurane Inhalation vs Remifentanil Infusion ........................................................ Sonia Ben Khalifa, Sami Blidi, Mehdi Trifa, Alia Skhiri,
Mehdi Drira, Tarek Regaya and Amjed Fekih Hassen
277
case reports
Anesthetic Implications Of Acute Methylenedioxymethamphetamine Intoxication In A Patient
With Traumatic Intracerebral Hemorrhage
............................................... Samuel DeMaria Jr, Ethan O Bryson and Elizabeth AM Frost
Human Poisoning After Ingestion Of Puffer Fish Caught From Mediterranean SEA
281
....................... Suheil Chucrallah Chamandi, Kamal Kallab, Hanna Mattar and Elie Nader
285
Failure Of Endtidal Carbon Dioxide To Confirm Tracheal Intubation In A Neonate With A
single Ventricle And Severe Pulmonary Stenosis
..................... Sahar M Siddik-Sayyid, Anis S Barka, Farah H Mokadem and Marie T Aouad
289
Uneventful Epidural Analgesia In A patient With Cyclic Idiopathic Thrombocytopenia
.......................................................................... Sami M Ibrahim and Mustafa Saleh Elgazali
136
291
The Rate Dependent Bundle Branch Block
- Transition from left bundle branch block to intraoperative normal sinus rhythm ........................................................ Seema Mishra, Prashant Nasa, Gaurav Nirwani Goyal,
Himanshu Khurana, Deepak Gupta and Sushma Bhatnagar
295
Intubation-Induced Tracheal Stenosis: The urgent need for permanent solution
............................................................................... Ali S Al-Qahtani and Farouk M Messahel
299
Obstruction Of Endotracheal Tube: A Manufacturing Error
................................................................................ Fatemeh Hajimohammadi, Arman Taheri
and Payam Eghtesadi-Araghi
303
Tracheal Cartilage Fracture With The Precutaneous Dilatational Tracheostomy
Ciaglia Method
............................................... Kasra Karvandian, Ata Mahmoodpoor, Mostafa Mohammadi,
Mohammadtaghi Beigmohammadi and Afshin Jafarzadeh
307
Ventriculo-Peritoneal Shunt Surgery In An Infant With Double Aortic Arch, Patent Ductus
Arteriosus And Atrial Septal Defect
... Mandeep Singh, Ashish Bindra, Girija P Rath, Vishwas Malik and Hemanshu Prabhakar
309
Anesthesia For Nelson’s Syndrome
........................................................ Madhur Mehta, Girija P Rath and Gyaninder Pal Singh
313
Sudden Cardiac Arrest During Cesarean Section: A Possible Case Of Amniotic Fluid
Embolism
........ Nikooseresht Mahshid, Sadegian Ahmad, Manochehrian Nahid and Farhanchi Afshin
315
Perioperative Care Of A Child With Ulllrich Congenital Muscular Dystrophy
.................................................................................. Neesann Puangsuvan, Robert A Mester,
Venkataraman Ramachandran and Joseph D Tobias
319
letter to the editor
Practice Guidelines And Prevention Of Obstetric Anesthesia-Related Maternal Mortality
.......................................................................................................... Krzysztof M Kuczkowski
325
Tongue Swelling In A Child After Cleft Palate Surgery
.............................................................. Kerem Erkalp, Zehra Yangin, Gokcen Basaranoglu,
Haluk Ozdemir, Yavus Haspolat and Leyla Saidoglu
327
Requested Change............................................................................................................................
329
Guideines For Authors. ...................................................................................................................
137
M.E.J. ANESTH 20 (2), 2009
138
IN MemoriUm... Dr. Carlos Parsloe
On behalf of the Editorial Board of the Middle East Journal of Anesthesiology (MEJA),
I announce with deep sorrow the passing away of Dr. Carlos Parsloe, the Former President of
the World Federation of Societies of Anaesthesiologists. (WFSA)
Dr. Carlos Parsloe was regularly participating in the different anesthesia Conferences, not
only in Brazil, his homeland, but also all over the World. (Fig. 1)
The last time I met Dr. Carlos Parsloe was during the 14th World Congress of
Anesthesiologists, Cape Town 2nd – 7th March 2008, when he looked as if saying Good Bye
(Fig. 2).
Fig. 1
Dr. Carlos Parsloe with the
President of the Brazillian Society of
Anesthesiologists and Dr. Baraka as
invited speaker, during the Brazillian
Society of Anesthesiologists Congress
in 1998.
Fig. 2
Dr. Carlos Parsloe during the 14th
World Congress in Cape Town,
2008 with Dr. Angela Enright,
President Elect WFSA, and Dr.
Anis Baraka.
Dr. Carlos Parsloe will be missed by the WFSA, as well as by all his colleagues in Brazil and
allover the World.
Anis Baraka, MD, FRCA (Hon)
Emeritus Professor, American University of Beirut
Emeritus Editor-in-Chief, Middle East Journal of
Anesthesiology
139
M.E.J. ANESTH 20 (2), 2009
141
Editorial
PREOXYGENATION OF THE MORBIDLY OBESE
WITH OBSTRUCTIVE SLEEP APNEA
Morbid obesity is associated with a more rapid
decrease in oxygen saturation during apnea following
induction of anesthesia, compared to patients who
have normal weight1. This is particularly hazardous as
morbid obesity, complicated by obstructive sleep apnea,
may be associated with an increased risk of difficult
tracheal intubation and difficult face mask ventilation2.
These morbidly obese patients, with a body mass
index >35 kg/m2, a history of obstructive sleep apnea,
a neck circumference >17 inch, a short thyromental
distance, and a Mallampati class III, suggest difficult
mask ventilation, difficult tracheal intubation, as well
as rapid oxyhemoglobin desatruation during apnea
(Fig. 1).
The more rapid hemoglobin desaturation may be
attributed to increased oxygen consumption, associated
with a decreased functional residual capacity of
the lung (FRC), which is the main oxygen store. In
addition, the supine position further decreases the FRC
due to the cephalad displacement of the diaphragm
by the abdominal content. Also, induction of general
anesthesia will result in an additional reduction of
the FRC. Whereas the FRC of the non-obese patients
decreases by approximately 20% following induction
of anesthesia, it decreases by approximately 50% in
the morbidly obese patients. Thus, the tidal volume of
the morbidly obese patient may fall within the closing
capacity, resulting in microatelectasis and ventilationperfusion (V/Q) mismatch, with a subsequent increase
of the alveolar-arterial oxygen gradient associated with
10-20% intrapulmonary shunt, compared to 2-5% in
the non obese patients.
In the morbidly obese patient, the time taken
for the oxygen saturation to fall to 90% during apnea
following standard preoxygenation by tidal volume
breathing of oxygen for 3 minutes, is significantly
reduced compared to the time taken in non-obese
patients. The head-up position has been recommended
to optimize preoxygenation in non-obese patients3,
as well as in morbidly obese patients4. The head-up
position during preoxygenation in the morbidly obese
patients has been shown to prolong the mean time of
desaturation by about 50 seconds. The application of
continuous positive airway pressure (CPAP) during
preoxygenation has been suggested to optimize
preoxygenation in the morbidly obese on the assumption
that CPAP will increase the FRC5. However, CPAP
only resulted in nonsignificant increase of the mean
Fig. 1
A morbidly obese male patient, with a body mass
index (BMI) 35 kg/m2, a history of obstructive
sleep apnea, a neck circumference 17 inch, a
short thyromental distance, and a Mallampati
score class III, suggesting difficult mask
ventilation, and difficult tracheal intubation,
as well as rapid oxyhemoglobin desaturation
during apnea
M.E.J. ANESTH 20 (2), 2009
142
time to desaturation to 90%, as the FRC will return to
pre-CPAP levels once the patient is anesthetized and
the CPAP mask is removed.
Recently, it has been shown in the morbidly obese
patients, that nasopharyngeal oxygen insufflation
following preoxygenation delays the onset of
oxyhemoglobin desaturation during the subsequent
apnea by apneic diffusion oxygenation6. In contrast,
preoxygenation without subsequent nasopharyngeal
oxygen insufflation in the morbidly obese patients,
is followed by a more rapid desaturation during
the subsequent apnea, associated with a significant
negative correlation between the body mass index and
the time to oxyhemoglobin desaturation7.
In the critically ill morbidly obese patient suffering
from respiratory failure, traditional preoxygenation
without or even with subsequent nasopharyngeal
oxygen insufflation may not significantly increase the
FRC oxygen store, and improve the oxygen saturation
before, during or after tracheal intubation. This may
be attributed to the significant atelectasis and decrease
of the FRC in these patients which results in marked
intrapulmonary shunting associated with a significant
increase of the alveolar-arterial oxygen gradient. In this
situation, the use of noninvasive bilevel positive airway
pressure (BiPAP) during preoxygenation can improve
alveolar recruitment and decrease derecruitment with
a consequent decrease of the significant ventilationperfusion mismatch and the alveolar-arterial oxygen
gradient. BiPAP preoxygenation can achieve a notable
increase of oxyhemoglobin saturation associated
with less hypercarbia, as compared to the traditional
technique of preoxygenation8.
Baillard et al showed in the critically ill patients
that noninvasive ventilation (provided in the form of
pressure support ventilation) in the intensive care unit
setting ensured improved oxygen saturation before,
during and after endotracheal intubation as compared
with the standard preoxygenation technique; Baillard
showed that a significant linear correlation exists
between SpO2 at the end of preoxygenation and the
minimal SpO2 during tracheal intubation9. Also, Baraka
et al have demonstrated with different techniques of
preoxygenation, that rapid oxyhemoglobin desaturation
during the subsequent apnea will occur whenever SpO2
decreases below 99%10,11.
In conclusion, traditional preoxygenation
is adequate in the non obese patient. However,
nasopharyngeal oxygen insufflation following
preoxygenation is indicated in the morbidly obese
patients. In the critically ill morbidly obese patient,
complicated with respiratory failure, BiPAP
preoxygenation is indicated to recruit the atelectatic
alveoli and decrease the significant ventilationperfusion mismatch, with a subsequent increase of
SpO2 before, during and after tracheal intubation.
Anis Baraka, MD, FRCA (Hon)
Emeritus Professor of Anesthesiology
Emeritus Editor-in-Chief, Middle East Journal of
Anesthesiology
References
1. Jense HG, Dubin SA, Silverstein PJ, et al: Effect of obesity on safe
desaturation of apnea in the anesthetized humans. Anesthesia and
Analgesia; 1991, 72:89-93.
2. Baluch A, Mahbubeni S, Al-Fadhli F, Kaye A: Anesthetic care of
the patient with obstructive sleep apnea. Middle East Journal of
Anesthesiology…
3. Baraka AS, Hanna MJ, Jabbour SI, et al: Preoxygenation in the
head-up versus supine position. Anesthesia and Analgesia; 1992,
75:757-759.
4. Dixon BJ, Dixon JB, Carden JR, et al: Preoxygenation is more
effective in the 250 head-up position than in the supine position in
severly obese patients. Anesthesiology; 2005, 102:1110-1115.
5. Cressy DM, Berthand MC, Reilly CS: Effectiveness of continuous
positive airway pressure to enhance preoxygenation in the morbidly
obese woman. Anesthesia; 2001, 56:670-689.
6. Holmdahl MH: Pulmonary uptake of oxygen, acid-base metabolism
and circulation during prolonged apnoea. Acta Chirurgica
Scandinavica; 1956, 212:1-128.
7. El-Khatib MF, et al: Supplementation of preoxygenation in
morbidly obese patients using nasopharyngeal oxygen insufflation.
Anaesthesia; 2007, 62:769-773.
8. El-Khatib MF, Kanazi G, Baraka AS: Noninvasive bilevel
positive airway pressure for preoxygenation of the critically ill
morbidly obese patient. Can J Anesth; 2007, 54(9):744-747.
9. Baillard C, Fosse JP, Sebbane M, et al: Noninvasive ventilation
improves preoxygenation before intubation of hypoxic patients.
Am J Resp Crit Care Med; 2006, 174:171-177.
10.Baraka AS, Taha SK, Aouad MT, El-Katib MF, Kawkabani NJ:
Preoxygenation: Comparison of maximal breathing and tidal
volume breathing techniques. Anesthesiology; 1999, 91:612-616.
11.Baraka A, Aouad M, Taha S, El-Khatib M, et al: Apnea-induced
hemoglobin desaturation during one-lung vs two-lung ventilation.
Can J Anesth; 2004, 47:58-67.
Review articles
ANESTHETIC CARE OF THE PATIENT
WITH OBSTRUCTIVE SLEEP APNEA
Amir Baluch*, Sunil Mahbubani**, Fahad Al-Fadhli***,
Alan Kaye**** and Elizabeth A.M. Frost*****
Introduction
Obstructive sleep apnea (OSA) is an insidious, progressive disease1 that is significantly under
diagnosed in the general population. It carries increased risk of difficult intubation preoperatively2
and increased risk of postoperative respiratory depression and airway collapse leading to hypoxia
and possibly asphyxia3. In light of the estimated prevalence of symptomatic OSA in 5%4 of the
general populace, and the fact that 80% of these patients remain undiagnosed5, it is crucial for
anesthesia personnel to screen every patient undergoing anesthesia for this disorder quickly and
effectively, and likewise, to have a strategy for perioperative care.
Definitions
Several commonly used terms include:
1.Obstructive Apnea: an absence of airflow during sleep for greater than 10 seconds6,7.
2.Obstructive Hypopnea: The latest manual of the American Academy of Sleep Medicine
(AASM) provides two definitions of hypopnea. The recommended definition is a drop in
airflow ≥30% from baseline lasting for at least 10 seconds and associated with a ≥4% oxygen
desaturation.
3.Obstructive Sleep Apnea: recurrent apneic and/or hypopneic episodes despite continuing
ventilatory effort, usually associated with a decrease of ≥4% in oxygen saturation6,7.
4.Obstructive Sleep Apnea Hypopnea Syndrome (OSAHS): symptomatic OSA. The main
symptom is daytime sleepiness, but symptoms can manifest as choking or gasping during sleep,
recurrent awakening during sleep, unrefreshing sleep, and impaired concentration6,7.
5.Apnea-Hypopnea Index (AHI): a tool used to diagnose and measure the severity of OSA by
measuring apneic-hypopneic events per hour during sleep. An AHI greater than 5 but less than
15 is the criteria for mild OSA. Moderate OSA is defined by an AHI greater than 15 but less than
30, and severe OSA is an AHI greater than 306. Respiratory Disturbance Index (RDI) is the same
measurement as AHI8.
*
MD, Anesthesia Resident, Jackson Memorial Hospital/University of Miami, Miami, Florida, USA.
** MD, Emergency Medicine Resident, Texas Tech University Health Sciences Center, El Paso, TX, USA.
*** MD, Department of Radiology, University of Mississippi Medical Center, Jackson MS, USA.
****MD/PhD/DABPM, Professor and Chairman, Department of Anesthesiology, Louisiana State University Health Science
Center, New Orleans, LA, USA.
***** MD, Professor, Mount Sinai Medical Center, New York NY, USA.
Corresponding author: Amir Baluch MD, Jackson Memorial Hospital, University of Miami, Miami, Florida, USA. E-mail:
[email protected]
The authors have no relationships with pharmaceutical companies or products to disclose, nor do they discuss off-label or
investigative products in this manuscript.
143
M.E.J. ANESTH 20 (2), 2009
144
Amir Baluch et. al
6.Sleep Disordered Breathing (SDB): a spectrum
of disorders based on irregular breathing during
sleep. It includes obstructive sleep apnea-hypopnea
syndrome, central sleep apnea syndrome (recurrent
apneic-hypopneic events during sleep without
upper airway obstruction), Cheyne-Stokes breathing
syndrome (the waxing and waning breathing patterns
of patients with cardiac dysfunction or intracranial
disease), and sleep hypoventilation syndrome
(hypoxia for greater than 50% of sleep without
apneic-hypopneic events)6.
7.Chronic Intermittent Hypoxia: the physiologic
terminology for chronic repetitive episodes of
oxygen desaturation and resaturation unique to SDB
disorders.
Epidemiology
Eighty percent of mild to severe OSA is
undiagnosed in the United States5. It is estimated that
20 million Americans have OSA9. Mild OSA is present
in 24% of men and 9% of women, or 20% of the total
population. OSA syndrome (OSAHS), or symptomatic
OSA, occurs in 5% of the population, 4% of men and
2% of women. The male to female ratio of OSA is
3:14. Race does not correlate significantly with OSA
prevalence.
As a person matures through middle age, the
risk for OSA increases and then plateaus at age 65.
Correspondingly, OSA is three times as prevalent in
the elderly as in middle age individuals, independent
of obesity or snoring10. Mechanisms proposed
for the age-related increase in prevalence include
increased deposition of fat in the parapharyngeal area,
lengthening of the soft palate, and changes in body
structures surrounding the pharynx11,12.
Fig. 11
Estimated Percent Change in AHI for Selected Decrements and
Increments of Percent Body Weight
Weight Change (%)
-20
-10
-5
5
10
20
Change in AHI (%)
-48
-26
-14
15
32
70
Obesity is the most common modifiable risk
factor for OSA. 90% of OSA patients have a BMI ≥283.
Lifestyle modifications aimed at losing weight are the
best way to decrease the number of nighttime apneas/
hypopneas. Changes in obesity have been shown to
directly correlate with disease severity (Figure 1)1.
Pathogenesis of Upper Airway Collapse
OSA is a progressive disorder of the obese4.
Fat deposition in the upper airway (UA) is most
common at the lateral pharyngeal walls, decreasing
pharyngeal caliber and adding external compression
forces on the pharynx13. The decrease in pharyngeal
size leads to increases in both UA resistance and
negative intrathoracic pressure14,15. A combination
of anatomical narrowing, a more collapsible airway,
and increasingly negative intrathoracic pressure,
predisposes OSA patients to UA collapse during sleep
and anesthesia16,17.
Repeat trauma induced by snoring18 can lead to
inflammation in mucosal and muscular layers of the
soft palate along with denervation of the upper airway
mucosa, resulting in decreased sensory and motor
activity in the upper airway in OSA patients19.
In the awake state, OSA patients with obstruction
at the genioglossus have increased genioglossal tone
(compared to non-OSA subjects) in order to maintain
pharyngeal patency. When continuous positive
airway pressure (CPAP) is applied, there is inhibited
genioglossal activity in OSA patients but little effect
in control subjects. This decrement in muscle activity
(with CPAP) in apnea (OSA) patients likely represents
inhibition of a neuromuscular reflex designed to
preserve airway patency20.
Sensory and motor denervation found in
OSA patients could lead to decreased activity of
neuromuscular reflexes designed to maintain patency.
Patients with OSA show evidence of UA tissue
damage, edema, and reduced UA mucosal sensation.
These changes may be brought on by the mechanical
events associated with nights/years of snoring and
repetitive nighttime obstructions. Such mechanical
events may cause peripheral nerve or muscle damage
and ultimately impair the ability of the UA to defend
itself from suction collapse21.
ANESTHETIC CARE OF THE PATIENT WITH OBSTRUCTIVE SLEEP APNEA
Collapse of the UA is determined by two
processes: a) increased airway resistance with an
associated increase in negative intrathoracic pressure,
and b) the loss of neuromuscular control of the
pharynx. Collapse most often occurs at multiple sites
within the pharynx with the most common site overall
being the nasopharynx where the soft palate contacts
the posterior pharyngeal wall22,23.
With UA collapse, the extra work of the diaphragm
causes increasingly negative intrathroracic pressure
along with concomitant hypoxia and hypercapnea.
Apnea-hypopnea episodes increase sympathetic
output up to 125% of normal levels, increasing muscle
tone, blood pressure, and other processes which cause
arousal. With arousal comes restoration of pharyngeal
dilator muscle tone, reoxygenation, and an abrupt
decrease in sympathetic response24.
Sequelae
Chronic intermittent hypoxia (CIH) is a newly
recognized physiologic phenomenon and shares
similarities with chronic hypoxia and ischemic
reperfusion injury25. Much about CIH and its long and
short terms effects are unknown. Known sequelae of
CIH are increased sympathetic output and oxidative
damage, sleep fragmentation, and the mechanical
effects of negative intrathoracic pressure.
Effects of increased sympathetic output
Sympathetic output during apneas or hypopneas
occurs in bursts of sympathetic activity, 125% above
normal. Repeated sympathetic burst activity increases
blood pressure upon termination of apnea. Over time,
nocturnal dysregulation of sympathetic responses
eventually leads to a tonic increase in sympathetic
output after arousal and elevation in diurnal blood
pressure24.
OSA is an independent risk factor for hypertension.
In a study by Logan et al., 34 of 41 patients (83%) in
a drug-resistant hypertensive population, were found
to be undiagnosed OSAHS patients26. CPAP decreases
nocturnal hypertension in OSAS patients with
refractory hypertension27. In severe OSA (OSAHS)
but not in mild cases, CPAP has been proven to lower
145
blood pressure28,29. Eleven to 37% of CHF patients have
been found to have OSAHS in prevalence studies. In
patients with CHF and OSAHS, treatment with CPAP
has been associated with increased ejection fraction,
lower systolic blood pressure, and decreased heart
rate30.
Consequences of increased oxidative
damage
The main atherogenic sequelae of OSA are
thought to occur through oxidative damage. CIH
brings about a significant increase in inflammatory
mediators, adhesion molecules, and free radicals, all
thought to contribute to endothelial dysfunction31.
OSAHS patients are at higher risk for stroke,
myocardial infarction (MI), unstable angina, coronary
artery disease, ischemic heart disease, and an increased
10-year risk for cardiovascular events. These risks can
be decreased with CPAP therapy31,32.
Stroke and transient ischemic attack (TIA)
populations have an increased prevalence of OSA
at 43 to 72%. Patients who suffer a stroke and have
OSA have increased functional impairment and longer
hospital stays. Treatment of OSA may lead to better
functional outcomes and increased rehabilitation of
patients with stroke30,32.
Another pathology postulated to be caused by
increased inflammatory mediators is insulin resistance.
Insulin resistance has been linked to increased levels
of tumor necrosis factor-α and interleukin-6, and both
of these inflammatory mediators are increased with
cyclical hypoxia as found in OSA and CIH. OSA has
been proven as an independent risk factor for both
glucose intolerance and insulin resistance independent
of BMI, visceral obesity, and waist-to-hip ratio33. Also,
CPAP has been shown to improve glycemic control in
Type 2 diabetic OSA patients34. CPAP can help improve
insulin sensitivity in OSA patients; however, obesity is
the primary determinant of insulin sensitivity. Harsch
and colleagues found that in OSA patients using CPAP
therapy, “patients with a BMI of less than 30 kg/m2
have a seven-fold higher chance of experiencing an
improvement in insulin sensitivity”.
M.E.J. ANESTH 20 (2), 2009
146
Sleep fragmentation
Repetitive episodes of microarousal produce
fragmented sleep15,24; and with chronicity, wakefulness
is impaired with increased daytime sleepiness and
decreased quality of life35. Not only is quality of life
affected, but patient safety is compromised. OSA
patients are at 2.5 times increased risk for traffic
accidents versus non-OSA patients36.
Mechanical effects of increasingly negative
intrathoracic pressure
Preload to the right heart increases as intrathoracic
pressure becomes more negative.
In hypertensive OSA patients, afterload is
increased, and the myocardium consumes more oxygen
to maintain cardiac output. Decreases in oxygenation
and increased myocardial oxygen demand during
events can produce subendocardial ischemia. Roughly
30% of OSAHS patients show increased nocturnal
cardiovascular events such as ST depressions, the
clinical significance of which has not been investigated
thoroughly37.
When coupled with all mechanisms of CIH,
the final pathological outcome of OSA has been
associated with congestive heart failure, systolic
and diastolic dysfunction, cerebral ischemia, cardiac
arrhythmias, pulmonary hypertension, cor pulmonale,
and pulmonary edema32,38.
Risk factors (Figure 2)22
The most prevalent risk factor for development
of OSA is obesity4. In the absence of neck masses,
such as goiters, increasing neck circumference is the
best correlate of disease progression and severity of
OSA3,39. Increasing age is another risk factor. Alcohol
has acute adverse effects of worsening AHI but has
unknown long term effects. Smoking worsens OSA
but its effects are reversible upon cessation10. But,
because former smokers do not manifest the increased
risk for obstructive sleep apnea, airway inflammation
and damage due to direct contact with cigarette smoke
could alter the mechanical and neural properties
of upper airway and increase collapsibility during
sleep40.
Amir Baluch et. al
Fig. 222
Risk factors and symptoms of OSA in adults
Demographical risk factors
1
2
3
Male
40-70 years of age
Familial aggregation
Suspected risk factors
1
2
3
4
5
Smoking
Genetics
Menopausal
Alcohol before sleep
Evening nasal congestion
Established risk factors
1
2
3
4
Obese or overweight
Central body fat distribution
Large neck circumference
Craniofacial/airway
Abnormalities
OSA Symptoms
1
2
3
4
5
6
Habitus
Snoring
Nocturnal periods of apnea
Choking
Gasping
Daytime sleepiness
Postmenopausal women have 4 times the risk
of OSA versus premenopausal women41, perhaps
secondary to decreased progesterone levels.
Ventilatory drive is increased during the luteal phase
of the menstrual cycle when progesterone levels are
highest42,43. Polycystic ovarian syndrome (PCOS) also
predisposes an increased risk for OSA, independent
of obesity. Increased circulating androgens secondary
to PCOS can increase soft tissue deposition in the
pharynx, affect function of pharyngeal dilator muscles,
and alter ventilatory control mechanisms44. Other risk
factors for OSA are: craniofacial disorder; retroposed
mandible/maxillae;
adenotonsillar
hypertrophy;
nasal pathologies: deviated septum, allergic rhinitis;
hyperthyroidism, acromegaly, and Down syndrome30.
Genetic factors also play a role. A first-degree
relative with OSA increases a person’s risk of having
OSA by 1.5 to 2 times independent of the genetics for
obesity45-47.
Anatomical narrowing of the UA is a risk factor
for apneic events during sleep or anesthesia17. Factors
that decrease skeletal confines of the tongue and
decrease pharyngeal dimensions predispose individuals
to OSA.
A patient with a difficult airway is also at risk.
Therefore, patients who are difficult intubations or
whose airway closes intraoperatively may benefit from
postoperative screening for OSA48. Screening positive
for OSA should trigger diagnostic procedures and
therapy.
Pre-operative Assessment
Screening for OSA
Due to its high prevalence and the high number
of undiagnosed OSA patients, all patients should be
screened for OSA49. Simple screening factors include
obesity, snoring or apneic episodes in sleep, daytime
sleepiness, and hypertension (Table1)50.
147
cervical angle, and the occlusal-geniohyoid angle,
correlate with both difficult intubation and increased
risk of OSA.
Predicting undiagnosed OSA
There are many prediction models of OSA in
previously undiagnosed patients. In general, OSA
prediction models are highly sensitive with poor
specificity51. Two prediction models are as follows:
1. Designed by Tsai et al., this model uses the
cricomental distance ≥1.5 cm as its basis (Fig. 3).
When the cricomental distance is ≥1.5 cm, OSA can be
excluded in a patient with a negative predictive value
of 100% (CI 95%). If cricomental distance is <1.5 cm,
the pharyngeal grade and overbite are assessed.
Fig. 350
Table 150
Univariate Obstructive Sleep Apnea Predictors
(using an RDI cutoff value of 10 hours1)
Variable
Odds
ratio
P value
95%
confidence
interval
Age
1.10
0.001
1.03,1.16
Epworth Sleepiness Scale
1.03
0.558
0.93,1.13
Snoring history
12.5
0.023
1.42,110.6
Choking episodes
2.02
0.169
0.74,5.49
Witnessed apneas
3.37
0.016
1.25,0.06
Hypertension
10.3
0.029
1.27,83.9
Pharyngeal grade, I-IV
1.52
0.046
1.01,2.30
Sampsoon-Young class, I-IV
1.77
0.018
1.1,2.86
Palatal Elevation
1.41
0.303
0.73,2.71
Overbite
2.19
0.044
1.02,4.70
Proven physical exam findings that are risk
factors for OSA are BMI ≥28, neck circumference >17
inches for men or >16 inches for women48, cricomental
distance ≤1.5 cm, pharyngeal grade greater than III or
IV, and presence of an overbite. Proven findings that
do not accurately predict the presence of OSA are
retrognathia, large tonsil size, enlargement of the uvula,
and a change in palatal elevation with phonation3,14,50.
Risk factors for OSA also correlate with risk
factors for difficult intubation. Mallampati score,
anterior mandibular depth, lower mandibular angle,
If pharyngeal grade is a III or IV (Fig. 4)50 and
overbite is present, OSA is assumed in a patient with
a sensitivity of 40% and a specificity of 96%. In the
study population, 60% of patients did not fall into
either category, leaving them in the “gray zone” of
M.E.J. ANESTH 20 (2), 2009
148
Amir Baluch et. al
diagnosis50.
2. Another prediction model is the “modified neck
circumference” described by Flemons. The patient
is screened for the following criteria: 1) snoring,
2) daytime sleepiness or drowsiness while driving,
and 3) obesity or hypertension. Patients who meet
at least 2 of the criteria are then measured for neck
circumference; the circumference is then ‘modified’ for
potential sequelae of OSA. If the patient has a history
of hypertension, 4 cm is added, a habitual snorer has
3 cm added; and a patient reported to choke or gasp
most nights has 3 cm added. A score of 43 cm or less
indicates low risk for OSA, 43-48 cm is intermediate
risk (4-8 times risk), and more than 48 cm indicates a
high risk for OSA (20x’s risk)52.
Fig. 4
Pharyngeal grading system. Class I = palatopharyngeal
arch intersects at the edge of the tongue. Class II =
palatopharyngeal arch intersects at 25% or more of the tongue
diameter. Class III = palatopharyngeal arch intersects at 50%
or more of the tongue diameter. Class IV = palatopharyngeal
arch intersects at 75% or more of the tongue diameter
50
abnormalities, (3) status of coexisting diseases, (4)
nature of surgery, (5) type of anesthesia, (6) need for
postoperative opioids, (7) patient age, (8) adequacy
of postdischarge observation, and (9) capabilities of
the outpatient facility.” Current ASA guidelines for
outpatient strategies are outlined in Table 249.
Table 249
Consult opinion on outpatient surgical procedures
in patients with OSA
Consult agrees procedure is safe
1
2
3
superficial surgery/local or regional
anesthesia
minor orthopedic/local or regional anesthesia
Lithotripsy
Consult is equivocal on procedure safety
1
2
3
4
superficial surgery/general anesthesia
tonsillectomy in age >3
minor orthopedic/general anesthesia
gynecologic laparoscopy
Consult is disapproves of safety
1
2
3
airway surgery
tonsillectomy in age <3
laparoscopic surgery/upper abdomen
Use of regional anesthesia
If a patient is suspected of having OSA and is
not yet diagnosed, adequate perioperative preparation
should be made.
Pre-operative sedation
Pre-operative sedation and medications should be
carefully chosen and administered in a setting that is
well supervised and includes O2 saturation monitoring21.
The presence of snoring and apneic events during
sleep may be unmasked by pre-operative sedation.
Due to sedatives increasing respiratory depression and
apnea, some authors have warned against the use of
preoperative sedation in OSA patients53.
Outpatient versus Inpatient
ASA guidelines for outpatient care in OSA
patients interprets many factors including, “(1)
sleep apnea status, (2) anatomical and physiologic
Regional anesthesia should be strongly considered
as the method of choice for OSA patients49. Under
regional anesthesia, patients do not lose conscious
reflexes that protect the airway. Use of regional
anesthesia may be technically difficult due to patient
body habitus and is limited by procedure type. Potential
poor outcomes of regional anesthesia are associated
with unintentional side effects if the regional block
spreads further than intended, and if better control of
the airway is needed mid-procedure due to heavier than
expected sedation. There is no evidence that regional
anesthesia is associated with better outcome for OSA
patients22.
Intra-operative Management
Pre-oxygenation
Pre-oxygenation may be technically difficult
in OSA patients. Due to obesity, functional residual
capacity is greatly reduced leading to faster oxygen
desaturation compared to non-obese patients54 because
of unopposed increases in intra-abdominal and intra-
thoracic pressures that decrease lung compliance and
impair PaO255-57. A recent study of preoxygenation in
the severely obese suggests that preoxygenation with
the head at 25 degrees elevation versus supine can
increase the time before arterial desaturation58.
Airway management requires a blend of proper
positioning, artificial airways, and may require
CPAP22. The importance of proper positioning and the
difficulty of repositioning in the obese patient should
not be underestimated59.
Preinduction positive end expiratory pressure
(PEEP) can increase time before oxygen desaturation
upon intubation. Preoxygenation with 100% FiO2 and
10 cm PEEP for 5 minutes before induction followed
by 10 cm PEEP with mask ventilation after intubation,
decreases postintubation atelectasis60. In a study
by Pelosi, et al, the use of 10 cm of water PEEP in
morbidly obese patients during the maintenance phase
of general anesthesia was shown to increase PaO2
throughout surgery, whereas in normal patients PEEP
had no significant effect on PaO2. Patients in the study
were taken to the ICU post-operatively and weaned off
PEEP gradually61.
Intubation of the OSA patient
OSA is a risk factor for difficult intubation2. The
intubation failure rate for OSA patients using direct
laryngoscopy is 5%, roughly 100 times the failure
rate of the general population – necessitating either
cancellation of cases or intubation via alternative
methods3. Laryngeal mask airways are useful
adjuncts. Further difficult airway management should
be performed according to ASA Difficult Airway
Guidelines 2003.
149
Extubation
As with all patients, complete reversal of
neuromuscular blockade must be ensured before
extubation, and extubation must be attempted in Stage
I, the analgesia stage, when the patient is conscious and
able to follow commands. Extubation is particularly
dangerous following OSA corrective surgeries as 5%
of patients have life threatening post-extubation airway
obstruction3. Airway collapse as a result of early
extubation can lead to rapid development of severe
negative pressure pulmonary edema from spontaneous
ventilation against an obstructed airway3.
For morbidly obese OSA patients undergoing
non-nasal or non-oral surgery, the decision to extubate
while awake or to maintain postoperative mechanical
ventilation should be considered. Factors in this
decision include ease of mask ventilation, difficulty
of tracheal intubation at the beginning of the case,
existing cardiopulmonary disease, length and type of
surgery, BMI, and severity of OSA (Fig. 5).
Criteria that should be fulfilled before extubation
are as follows:
1.The patient should be fully awake before extubation
- rational and responsive to commands. Mindless
reflex movement is not purposeful movement.
2.Full recovery from neuromuscular blockade must
be proven by both use of a neuromuscular blockade
monitor and a sustained head lift >5 s. In the ICU,
an adequate vital capacity (>15 cc/kg) and negative
inspiratory force (NIF) <-25cm H2O should be
present.
3.Concentration of serum narcotic should be titrated
to a spontaneous respiratory rate >12-14/min.
Fig. 5
Major determining factors when deciding awake
vs. asleep extubation during uvulopalatopharyngeoplasty
or nasal surgery
Individual factors
Factor status and extubation plan
BMI
AHI
Ease of mask ventilation
Ease of tracheal intubation
Experience at start of case
Associated cardiopulmonary
disease
If all factors good → patient may be asleep
If one factor severe → awake extubation
Factors in between extremes → requires clinical judgement
M.E.J. ANESTH 20 (2), 2009
150
Amir Baluch et. al
After extubation, the patient should be positioned
in reverse Trendelenburg at 30 degrees or upright as
these positions minimize compression of abdominal
contents against the diaphragm.
from the recovery area to an unmonitored setting (i.e.,
home or unmonitored hospital bed) until they are no
longer at risk for postoperative respiratory depression.
Adequacy of postoperative respiratory function may be
documented by observing patients in an unstimulated
environment, preferably while they seem to be asleep,
to establish that they are able to maintain their baseline
oxygen saturation while breathing room air”49.
Post-operative Management
Continuous positive airway pressure (CPAP)
If patients use CPAP machines preoperatively,
their machines should be available immediately after
surgery to decrease apneic events3. In the postoperative
setting, sleep is disturbed and patients are at increased
risk of apneic events during sleep for 1 week following
surgery62. For the first 3 days after surgery, the deeper
stages of sleep, non-rapid eye movement (NREM)
stages 3 & 4 and rapid eye movement (REM), are
suppressed. In post-operative days 4 through 6, REM
rebounds and natural deep sleep apnea increase63,64.
Pain management
OSA carries an increased risk of postoperative
complications, with most complications occurring
within 2 hours68,69. Judicious use of opioids and other
respiratory depressants used for pain management is
essential in the post-operative period, as OSA patients
are at increased risk for upper airway obstruction when
sedated70,71. Regional nerve blocks may be useful for
postoperative pain management. The judicious use of
post-operative narcotics and sedatives in patients with
OSA should be emphasized to healthcare professionals
involved in the patient’s care49,72.
Monitoring
Due to the increased risk of apnea, the monitoring
needs for these patients are more intense, and strategies
for dealing with them postoperatively vary from an
overnight stay in the ICU to a PACU environment with
a nursing ratio of 2 or 3:165. Deutscher and colleagues
provide a strategy to try to guide the level of care
needed for OSA patients based on the risk of surgery
and severity of OSA displayed in Table 366.
Conclusion
Obstructive Sleep Apnea (OSA) is an often
undiagnosed condition which presents many challenges
to the anesthesiologist. The prevalence of obesity in
world wide suggests that an increasing number of
patients with sleep apnea will present for surgery. OSA
frequently coexists with other disease processes such as
hypertension, congestive heart failure, and pulmonary
hypertension. An understanding of the pathophysiology
behind OSA is necessary to assure proper perioperative
management. Recent emphasis has been placed by
the American Society of Anesthesiologists on this
condition and guidelines for management have been
published.
Approximately
60%
of
postoperative
hypertension occurs in patients who have a history
of hypertension preoperatively67. OSA patients are at
risk for postoperative hypertension and blood pressure
should be closely monitored and controlled so as to
minimize the risk of surgical site bleeding.
Current ASA recommendations for monitoring
are that OSA patients, “should not be discharged
Table 366
Sleep Apnea Scale for Monitoring Needs Postoperatively
OSA Severity
Mild
Moderate
Severe
W
Surgical
Low
W/H
W/H
Risk
Intermediate
W
M/W
M
High
M/W*
M
M
*
*
M = monitored
area
W = standard ward
H = home
* = case by case
basis
151
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JM, Laurie CP, O’Brien PE: Preoxygenation is more effective in the
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obese patients: a randomized controlled study. Anesthesiology;
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60.Coussa M, Proietti S, Schnyder P, Frascarolo P, Suter M, Spahn
DR, Magnusson L: Prevention of atelectasis formation during the
induction of general anesthesia in morbidly obese patients. Anesth
Analg; 2004, 98:1491-5, table of contents.
61.Pelosi P, Ravagnan I, Giurati G, Panigada M, Bottino N, Tredici S,
Eccher G, Gattinoni L: Positive end-expiratory pressure improves
respiratory function in obese but not in normal subjects during
anesthesia and paralysis. Anesthesiology; 1999, 91:1221-31.
62.Dodds C: Sleep apnoea and anaesthesia. Recent Advances in
Anaesthesia and Analgesia; 1994, 18:179-85.
63.Reeder MK, Goldman MD, Loh L, Muir AD, Casey KR, Lehane
JR: Late postoperative nocturnal dips in oxygen saturation in
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patients, APSF Newsletter; Fall 2002.
66.Deutscher R BD, Sharma S: OSA Protocol promotes safer care,
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with obstructive sleep apnea submitted to surgery. Chest; 1995,
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Conservation of resources: indications for intensive care monitoring
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ANESTHESIA AND CARDIOPULMONARY BYPASS
FOR CONGENITAL HEART SURGERY
Chawki F.
el Z ein *
Normal Cardio-Respiratory Physiology In Neonates And Infants
The neonate has a limited respiratory reserve and is prone to ventilatory failure and hypoxemia.
They are mechanically disadvantaged by increased chest wall compliance, reliance on the diaphragm
as the main muscle of respiration and a reduction in functional residual capacity (FRC) with an
increase in closing capacity. Because of an increased metabolic rate, oxygen consumption is two
to three times the adult level, yet their oxygen reserve is diminished due to a reduction in FRC.
An increased proportion of total oxygen consumption is directed at the work of breathing and they
have a relative fixed tidal volume and rate-dependent minute ventilation.
The immature myocardium has a diminished contractile mass (30% compared to 60% in
mature myocardium), has a lower velocity of shortening, a diminished length tension relationship
and a reduced ability to respond to afterload stress. The stroke volume is relatively “fixed” and an
increase in cardiac output is heart rate dependent. The cytoplasmic reticulum and t-tubular system
are underdeveloped and the neonatal heart is dependent on transarcolemmal flux of extracellular
calcium to both initiate and sustain contraction.
The large surface area to body mass ratio of infants and neonates predisposes them to
hypothermia. This is a particular concern prior to induction of anesthesia. Hypoglycemia is also
a risk during preparation for surgery and induction because of limited metabolic reserve and
immaturity of the liver.
*
Chawki elZein, MD, Heart Institute for Children, Hope Children’s Hospital, 4440 West, 95th Street, Oak Lawn, IL 60453,
USA. Phone: (708) 6843029, Fax: (708) 6844068. E-mail: [email protected]
153
M.E.J. ANESTH 20 (2), 2009
154
Pathophysiology of Congenital Heart Defects
Pulmonary Blood Flow
1 – Increased flow
Increased pulmonary blood flow from an
unrestricted or excessive left-to-right shunt may
result in pulmonary hypertension and cardiac failure.
Pulmonary artery pressures (PAP) are initially labile,
but become fixed as pulmonary vascular obstructive
disease (PVOD) develops due to structural changes
in the pulmonary vasculature. The time course for
developing PVOD depends on the amount of shunting
and age at surgery. The progression to PVOD is more
rapid when both the volume and pressure load to the
pulmonary circulation is increased, such as with a large
ventricular septal defect (VSD). When pulmonary flow
is increased in the absence of elevated PA pressures,
as with an atrial septal defect (ASD), pulmonary
hypertension develops more slowly.
Respiratory work is increased in patients with
excessive pulmonary blood flow. Interstitial edema
and increased lung water from the elevated LV enddiastolic volume (LVEDV) and left atrial pressure
(LAP) reduce lung compliance. Small airways
resistance is increased by compression from distended
pulmonary vessels and lung hyperinflation is often
evident on chest X-ray. Patients may be tachypneic and
have limited functional reserve and exercise tolerance.
Large airways may also be extrinsically compressed
by dilated pulmonary arteries and the left atrium.
During anesthesia, pulmonary vascular resistance
and pressure may alter significantly secondary to the
pattern of ventilation, airway obstruction, FiO2, pH
and PaCO2.
2. Decreased flow
Pulmonary flow may be diminished secondary
to pulmonary outflow obstruction or increased
right-to-left intracardiac shunting. Patients are
cyanosed and desaturated readily, and anesthetic
management is directed at avoiding further reductions
in pulmonary flow. It may be difficult to distinguish
between the relative contributions of intracardiac and
intrapulmonary shunts to hypoxemia, and the PaO2
will be determined by the amount of intracardiac rightto-left shunt, pulmonary venous O2 content and mixed
Chawki F. elZein
venous O2 content.
The consequences of chronic hypoxemia also need
consideration. Polycythemia increases oxygen carrying
capacity, but when the hematocrit rises above 60%
the increased blood viscosity causes stasis, potential
thrombosis and exacerbates tissue hypoxia. Dehydration
must be avoided and intravenous maintenance fluids
commenced while fasting preoperatively. Ventricular
function may be compromised secondary to the
elevated pulmonary and systemic vascular resistances
and from myocardial ischemia. Bleeding disturbances
are common in cyanotic patients and may be due to
thrombocytopenia, defective platelet aggregation or
clotting factor abnormalities.
Single Ventricle/Parallel Circulation
The balance between pulmonary and systemic
blood flow is critical for patients with a “parallel
circulation” whereby a single ventricle supplies both
systemic and pulmonary flow. This balance is primarily
influenced by vascular resistance and the size of the
anatomic or surgically created shunt. Assuming normal
mixed venous and pulmonary venous saturations,
a systemic arterial saturation between 80-85% is
appropriate.
Strategies to limit pulmonary blood flow/
Increasing pulmonary vascular resistance
A fall in pulmonary vascular resistance (PVR) will
increase pulmonary blood flow and the volume load to
the ventricle in patients with a large left to right shunt,
e.g. VSD, complete atrio-ventricular canal (CAVC),
and patients with “parallel’ circulation physiology,
e.g. hypoplastic left heart syndrome (HLHS), systemic
to pulmonary artery shunts and truncus arteriosus.
Myocardial work is increased and, if pulmonary blood
flow is excessive, systemic perfusion may fall resulting
in hypotension and progressive acidemia. During
anesthesia PVR can be maintained or increased by
using a low FiO2 and altering ventilation to achieve a
normal pH and PaCO2. The addition of CO2 to the fresh
gas flow to promote a respiratory acidosis, or addition
of nitrogen to reduce the FiO2 are useful techniques for
raising PVR.
Care must be taken on induction as patients may
be relatively hypovolemic from diuretic therapy and
ANESTHESIA AND CARDIOPULMONARY BYPASS FOR CONGENITAL HEART SURGERY
preoperative fasting. Preload, contractility and heart
rate must be maintained; afterload reduction is well
tolerated and will reduce both pulmonary flow and
myocardial work.
Strategies to increase pulmonary blood flow/
Decrease PVR
Following repair of defects with large left-toright shunts, the PAP and PVR may initially remain
labile. Pulmonary vascular endothelial dysfunction
following bypass and ischemia/reperfusion has been
demonstrated by diminished response to acetylcholine,
an endothelial dependent vasodilator. Numerous
factors, however, contribute to increased PVR after
bypass. They include loss of lung volume and FRC
from atelectasis, pneumothorax and pleural effusion,
and increased lung water secondary to the inflammatory
response to bypass, excess pulmonary venous return
during bypass and inadequate venting. Maneuvers to
help control. PVR include:
a. Attenuation of the stress response with deep
anesthesia and paralysis.
b. Manipulation of gas exchange using a high inspired
oxygen concentration, hyperventilation to induce a
respiratory alkalosis, and bicarbonate to maintain
a metabolic alkalosis. Ideally the pH should be
around 7.50 and the arterial CO2 30 mmHg. As a
cautionary note, vigorously inducing a respiratory
alkalosis after bypass may be detrimental because
cerebral blood flow is reduced and the oxygenhemoglobin curve shifts to the left.
c. The pattern of ventilation and maintenance of lung
volumes is important; atelectasis and a decrease
in lung compliance may cause a significant rise in
PVR. Conversely, hyperinflation with excessive
lung volumes and PEEP will also increase PVR.
Changes in ventilation must be made cautiously
and frequently reassessed.
d. Pharmacologic manipulation. PA smooth muscle
relaxation either via c-GMP (Nitric Oxide, Sodium
Nitroprusside) or c-AMP (Isuprel, prostacyclin,
prostaglandin).
Ventricular Failure
Congestive heart failure (CHF) may develop
from a volume or pressure load imposed on the
155
ventricles. Considerable remodeling of the ventricles,
and recovery of function, is possible after reconstructive
surgery, but the time course over which irreversible
ventricular dysfunction develops is variable. Generally,
if surgical intervention to correct the volume overload
is undertaken within the first 1 to 2 years of life,
residual dysfunction is uncommon. As the time course
to develop significant ventricular dysfunction is longer
in patients with a chronic pressure load compared to a
chronic volume load, symptoms may not be apparent
unless the obstruction is severe and prolonged.
A volume load may result from an excessive left
to right shunt and valve regurgitation. For patients
with a left to right shunt, as PVR decreases in the first
2 months after birth, and the hematocrit falls to its
lowest physiologic value, pulmonary blood flow and
ventricular volume load, will increase. These patients
often present with failure to thrive and signs of CHF,
requiring initial stabilization with digoxin, diuretics
and vasodilators. Corrective or palliative surgery
is performed early to limit pulmonary flow and its
sequelae.
Mechanical ventilation
The importance of ventilation management
during anesthesia, before and after cardiopulmonary
bypass (CPB) cannot be over-emphasized. Besides
influencing gas exchange, the pattern of ventilation,
effect on lung volumes and changes in intrathoracic
pressure are critical for optimal cardio-respiratory
interaction.
The increase in mean intrathoracic pressure
during mechanical ventilation is beneficial for patients
with CHF because ventricular wall stress is reduced by
a fall in ΔP across the myocardium (LaPlace’s law). On
the other hand, output from the pulmonary ventricle
may be reduced during positive pressure ventilation
secondary to a reduction in preload and increase in
afterload in patients with poor RV compliance and
outflow obstruction.
Following a modified Fontan procedure,
where pulmonary flow is dependent on the pressure
gradient from the RA to LA, a significant increase in
intrathoracic pressure from excessive peak inspiratory
pressure or positive end expiratory pressure (PEEP)
may severely reduce pulmonary flow; early resumption
of spontaneous ventilation is recommended.
M.E.J. ANESTH 20 (2), 2009
156
Anesthesia
The induction of anesthesia is a critical time and
must proceed as efficiently as possible to reduce stress
in patients with limited cardio-respiratory reserve. For
most cases, invasive monitoring lines are not in place
prior to induction, and noninvasive monitoring with
pulse oxymetry, blood pressure and electrocardiography
(ECG) is necessary.
A number of induction techniques can be used
depending on myocardial function and pulmonary
reserve. Inhalational induction with volatile anesthetics
such as halothane and sevoflurane are commonly used
for general pediatric anesthesia, and are suitable for
most patients with congenital heart disease (cyanotic
and non-cyanotic) provided myocardial function
is preserved. However, the myocardial depressant
effect of these agents on the immature myocardium
means these techniques should be used with caution
in infants and neonates with complex congenital heart
diseases (CHD). Further, loss of airway patency,
obstruction and hypoventilation can lead, to early
onset of desaturation and bradycardia. Intravenous
(IV) induction is preferable although IV access may
be difficult, particularly in patients who have had
multiple surgical procedures. Considerable stress and
hypothermia, may result in the neonate and infant if
excessive time is taken trying to establish intravenous
access. In these situations, an intramuscular induction
can be used.
Following induction and securing of the airway,
arterial and central venous lines are placed. Once again
it is important not to waste time trying to establish
percutaneous access and an arterial cut-down should be
considered if there are any difficulties. Central venous
access is rarely required pre-bypass unless inotropic
support is necessary or there are concerns about
potential bleeding. Transthoracic lines can be placed
prior to discontinuing bypass and used for monitoring,
drug infusions, and volume replacement.
Factors influencing anesthesia management
include patient age, preoperative clinical condition,
surgical procedure, bypass duration, degree of
hypothermia and the anticipated postoperative
management. Most patients having complex repairs,
particularly neonates and infants, are anesthetized with
a high dose opioid combined with pancuronium and an
air/oxygen gas mixture. Neonates and infants generate
Chawki F. elZein
a significant humoral and metabolic response to
stress. Lactic acidemia, hyperglycemia, high levels of
catabolic hormones, and a negative nitrogen balance,
greater incidence of sepsis, DIC and even death during
the postoperative period, have been demonstrated
in neonates who have undergone cardiac surgical
procedures with anesthetic techniques that failed to
suppress the stress response. High doses of the synthetic
opioids fentanyl (75-100 mcg/kg) and sufentanil (5-10
mcg/kg) provide reliable hemodynamic stability and
suppression of the stress response. Additional doses
are required during cardiopulmonary bypass because
opioid levels decrease significantly in children
secondary to hemodilution, drug binding to the circuit
and increased volume of distribution. Benzodiazepines
provide additional suppression of the stress response
and amnesia.
Patients undergoing less complex surgery and
who have been stable preoperatively can be managed
with a combination of opioids and inhalational agent,
thereby allowing an earlier wean and extubation in the
cardiac intensive care unit.
Fast Track management with early extubation
is also applicable to children. Provided patients
are hemodynamically stable, have satisfactory gas
exchange and have no surgical complications such
as bleeding, most children undergoing elective repair
should be suitable for early extubation.
Cardiopulmonary Bypass
Inflammatory response
There may be significant morbidity associated
with bypass in neonates and infants that compromises
subsequent recovery from surgery. First, the large
pump surface area and priming volume relative to
blood volume increases the exposure of blood to nonendothelialized surfaces and increases inflammatory
mediator release. Second, deep hypothermic circulatory
arrest or low flow bypass is more commonly used
which increases the risk of ischemia / reperfusion
injury. The humoral responses include activation of
complement, kallikrein, eicosinoid and fibrinolytic
cascades; cellular responses include platelet activation
and an inflammatory response that stimulates neutrophil
activation and release of proteolytic and vasoactive
substances.
ANESTHESIA AND CARDIOPULMONARY BYPASS FOR CONGENITAL HEART SURGERY
Over recent years the intimate relationship
between the systemic inflammatory response and
endothelial injury to bypass has been investigated and
strategies to attenuate the response evaluated.
1. Treating the consequences of endothelial injury
a. Stress response attenuation.
b. Modification of pump prime: Maintaining a higher
hematocrit and colloid oncotic pressure in the
bypass perfusate may reduce edema and has also
been demonstrated to improve cerebral recovery
after deep hypothermic circulatory arrest.
c. Delayed sternal closure: The inflammatory
response with capillary leak and edema following
cardiopulmonary bypass continues into the
postoperative period and may compromise
myocardial and pulmonary function. Sternal
closure may cause a constrictive or tamponade
effect, and delayed closure be necessary once
mediastinal edema has diminished.
d. Hemofiltration: Besides hemoconcentration,
inflammatory mediators including complement
and the cytokines, IL-6, IL-8, IL-1ß and TNF
are also removed by a process of convection
and adsorption. Improved systolic and diastolic
pressures are observed during filtration and
improved pulmonary function has also been noted
with reduction in pulmonary vascular resistance
and total lung water. The duration of ventilation
postoperatively, pediatric ICU and hospital stay
has also been reduced.
Hemofiltration techniques include:
i. Modified ultrafiltration (MUF): of the patient
blood volume after completion of bypass.
ii. Conventional hemofiltration: both the patient and
circuit are filtered during bypass.
iii. Zero-balance ultrafiltration: recently described,
high volume ultrafiltration essentially washes
the patient and circuit blood volumes during the
rewarming process.
2. Modifying inflammatory mediator release
157
kg upon induction of anesthesia.
c. Aprotinin: Non-specific serine protease inhibitor.
Besides antifibrinolytic properties, aprotinin also
attenuates the inflammatory response by inhibiting
thrombin and kallikrein release, and elastase release
following the neutrophil respiratory burst. There
has been recent literature demonstrating a high
incidence of kidney dysfunction from aprotinin
in adults following cardiac surgery. This was
inconclusive, however, and was not demonstrated
in the pediatric age group.
3. Adhesion molecule modification
Significant advances are being made in the
development of drugs that will prevent the adhesion
molecule/endothelial interaction which is pivotal in
the inflammatory response.
Hypothermia
Because of the large body surface area to mass
ratio in neonates and infants, a 2-3° C reduction in
core temperature is common following induction of
anesthesia and prior to bypass. The use of cooling/
warming blankets, low ambient temperature and
reduced overhead operating light intensity helps
maintain a low temperature during bypass and
minimizes radiant heating of the myocardium. Surface
cooling is aided by placement of ice bags on and
around the head and will assist with brain cooling.
Despite full rewarming, mild hypothermia after
discontinuing bypass often develops in neonates
and infants. Active measures to decrease radiant
and evaporative losses are necessary because of the
increased metabolic stress, pulmonary vaso-reactivity,
coagulopathy and potential for dysrhythmias associated
with hypothermia. However, hyperthermia must be also
avoided because of the associated increased metabolic
demand, particularly when myocardial function may
be depressed and cerebral autoregulation impaired.
There are two broad bypass management
strategies:
a. Hypothermia.
1. Deep hypothermia (<18°C) with low/intermittent
flow or circulatory arrest
b. Steroids: Commonly used, but inconclusive
benefit. A dose of 30 mg/kg of Solumedrol is given
the night of surgery, followed by a dose of 10 mg/
Deep hypothermic circulatory arrest (DHCA)
provides optimal operating conditions for intracardiac
repairs with an empty relaxed heart, and reduces the
M.E.J. ANESTH 20 (2), 2009
158
duration on bypass and exposure of circulating blood
to foreign surfaces. Prolonged ischemia to the brain is
a major disadvantage and is both time and temperature
dependent.
Low flow deep hypothermic bypass is preferable
with improved neurologic protection. Flow rates
between 30-50 ml/kg/min are often referred to as “low
flow”, but the optimal flow rates during low flow bypass
are not firmly established. Flows as low as 10 cc/kg
have been used in animal studies evaluating low flow
bypass, with maintenance cerebral phosphocreatine,
ATP and intracellular pH at or above baseline both
during bypass and reperfusion.
2. Moderate hypothermia with normal or increased
pump flow
Bi-caval cannulation is generally used. The risk
of cerebral ischemia is reduced, but CPB is prolonged
and operative conditions may not be ideal.
Pump flow rates are generally higher in neonates
and infants, reflecting the increased metabolic rate.
During bypass, there is no one measure of index that
assures adequate perfusion. Generally, flow rates of 100150 ml/kg/min, or indexed flows to 2.2-2.5 L/min/m2,
should provide adequate flow at normothermia. Venous
oxygen saturation greater than 75% suggests adequate
perfusion. However, these values may be misleading in
patients with poor venous drainage, severe hemodilution,
malposition of the aortic cannula or in the presence of a
large left to right shunt. On-line continuous monitoring
of blood gas and saturation of oxygen is important to
identify trends in oxygen extraction.
Chawki F. elZein
Coagulopathy
Hemostasis may be difficult to obtain if bypass
has been prolonged and if there are extensive suture
lines. Prompt management and meticulous control
of surgical bleeding is essential to prevent the
complications associated with massive transfusion.
Besides hemodilution of coagulation factors
and platelets, complex surgery with long bypass
times increases endothelial injury and exposure to
the non-endothelialized surface of the pump circuit,
thereby stimulating the intrinsic pathway, and platelet
activation and aggregation. Pre-operative factors
including chronic cyanosis in older patients, and a
low cardiac output (CO) with tissue hypoperfusion
and disseminated intravascular coagulation (DIC),
hepatic immaturity, and the use of platelet inhibitors
such as prostaglandin E1 in neonates and infants, also
contribute to prolonged bleeding after bypass.
Weaning from CPB
Weaning from CPB is attempted once the patient
is evenly rewarmed, ionized calcium and electrolytes
are corrected, and inotropes or vasoactive infusions
commenced where indicated. Failure to wean from
bypass may be due to primary myocardial failure,
however residual lesions such as shunts, valve
regurgitation, outflow obstruction and change in
pulmonary flow must be excluded. Transesophageal
echocardiography, oxygen saturation measurements
and pull-back pressures are used to diagnose residual
abnormalities.
References
1. “Anesthesia for Cardiovascular Surgery”. Kirklin textbook of
Cardiac Surgery. Third edition; 1:169-173.
2. “Effect of Cardiopulmonary Bypass and aortic clamping on functional
residual capacity and ventilation distribution in Children”. Journal of
Thoracic and Cardiovascular Surgery; 2007 Nov, 134(5):1193-8.
3. “Anesthetic Management for the pediatric patient undergoing deep
hypothermic circulatory arrest”. Seminars in Cardiothoracic and
Vascular Anesthesia; 2007 March, 11(1):16-22.
4. “Efficacy of combined modified and conventional ultrafiltration
during cardiac surgery in children”. Annals of Cardiac Anesthesia;
2007 Jan, 10(1):27-33.
5. “Modified and conventional ultrafiltration during pediatric cardiac
surgery, clinical outcomes compared”. Journal of Thoracic and
Cardiovascular Surgery; 2006 Dec, 132(6):1291-8.
6. “Postoperative management in patients with complex congenital
heart disease”. Seminars in Thoracic and Cardiovascular Surgery.
Pediatric Cardiac Surgery Annual; 2002, 5:187-205.
7. “Preoperative high dose Methylprednisolone attenuates the cerebral
response to deep hypothermic circulatory arrest”. European Journal
of Cardiothoracic Surgery; 2000 March, 17(3):279-86.
8. “Aprotinin in Pediatric cardiac operations: a benefit in complex
malformations and with high-dose regimen only”. Annals of
Thoracic Surgery, 1998 July, 66(1):153-8.
PREVENTING PARALYTIC ILEUS: CAN THE
ANESTHESIOLOGIST HELP
Elizabeth A.M. Frost*
Introduction
Gastrointestinal (GI) function is readily altered by many factors including opioid administration.
In the postoperative period and in patients who require long-term or terminal care narcotic usage,
which essentially may have severe side effects and prolong hospital stay and increase patient
discomfort.
Patients who are at greatest risk for developing postoperative ileus especially can be identified
and practitioners can use newer management modalities that are designed to hasten recovery.
While there are several current management strategies, they are associated with advantages
and disadvantages. Pharmacoeconomic benefits to enhanced management of ileus may be
considerable.
Definitions
Ileus is defined as the functional inhibition of propulsive bowel activity, irrespective of
pathologic mechanisms. It is commonly associated with long-term opioid use and results often in
debilitating constipation. Postoperative ileus (POI) is the transient cessation of coordinated bowel
motility after surgical intervention, which prevents effective transit of intestinal contents and/or
tolerance of oral intake. It is termed primary in the absence of any precipitating complication and
secondary if some predisposing complication exists. Paralytic ileus is a form of POI that lasts
longer than 5 days after surgery2.
Postoperative Ileus
The average time to resolution of POI after major abdominal surgery depends in part on the
section of the GI tract affected by the surgery: For the small intestine, POI usually will last about
0-24 hours; for the stomach, it will last 24-48 hours; and for the colon, 48-72 hours. However, while
the incidence of POI is greatest after bowel surgery (15-20%), it also occurs after hysterectomy
(4%), cholecystectomy (8.5%), appendectomy (6%) and averages 9% for other procedures for an
overall incidence of about 8.5% for all procedures1.
*
Elizabeth AM Frost MD, Clinical Professor of Anesthesia, Mount Sinai Medical Center, New York, NY, USA.
Phone: (212)241-7467. E-mail: [email protected]
159
M.E.J. ANESTH 20 (2), 2009
160
Elizabeth AM Frost
Effects
The manifestation and consequences of POI are
considerable. Passage of flatus and stool are delayed.
Postoperative pain and cramping are increased, as
are nausea and vomiting. If oral intake is sufficiently
delayed, parenteral nutrition may have to be instituted.
Wound healing is poor and postoperative mobilization
is slowed. The risk of other complications such as
pulmonary problems and nosocomial infections
increases. Patient satisfaction is reduced as
hospitalization is prolonged and healthcare costs rise.
Causes
The neural regulation of the digestive tract
involves both intrinsic and extrinsic control systems.
Intrinsic control is mediated via the enteric nervous
system within the gut wall where neurons regulate
both motility and secretion. Response to local and
extrinsic events occurs. Extrinsic control is governed
by the autonomic nervous system, which integrates gut
function into the homeostatic balance of the body.
Alterations in other mechanisms contribute to
the pathogenesis of POI as do several other pathways
and mediators. In fact, the pathogenesis of POI is
multifactorial. Minimizing any of the adverse effects
could shorten the duration of POI and reduce morbidity
(Fig. 1).
Fig. 1
The pathogenesis of POI is multifactorial
opioids (produced by pain) and exogenous opioids
(given to relieve pain) reduce propulsive activity. The
autonomic nervous system stimulates sympathetic
inhibitory pathways. The enteric nervous system
releases substance P. General anesthesia may also
inhibit gut function.
Opioids have a profound effect on the GI tract.
Endogenous opioids are released as part of the stress
response. Exogenous opioids are the most commonly
used analgesics today. Both types of opioids activate
the same receptor sites and decrease motility, secretion
and the transport of fluids and electrolytes. As opioids
inhibit peristaltic activity, gastric emptying and gut
transit times are reduced and POI may be precipitated.
Management Strategies
Traditional strategies for management of POI
have emphasized prevention and supportive care.
Prevention revolves around anesthetic choice, surgical
technique, use of opioid-sparing analgesia, early
feeding and preoperative psychological preparation.
Supportive care involves placement of a nasogastric
tube, mobilization, fluid restriction and administration
of prokinetic agents (Table 1).
Table 1
Traditional Strategies for Managing Postoperative Ileus
Prevention
Supportive Care
Epidural vs. general
anesthesia
Nasogastric tube
Epidural vs. general
anesthesia
Early mobilization
Laparoscopic techniques
and minimal bowel
manipulation when
possible
IV fluid restriction
Early feeding
Prokinetic agents, but
evidence puts effectiveness
into question, and side
effects may outweigh any
benefit
Reproduced courtesy of Network for continuing Education, New Jersey
For example, gut manipulation results in the
production of inflammatory mediators such as nitric
oxide and vasoactive intestinal peptide. Macrophage
and neutrophil infiltration can occur. Both endogenous
Preoperative
psychological preparation
Opioid-sparing analgesia,
such as NSAIDS
PREVENTING PARALYTIC ILEUS: CAN THE ANESTHESIOLOGIST HELP
Anesthetic Choice
All agents used for induction and maintenance
of general anesthesia may depress gastric motility.
Reduced ileus is a significant benefit of epidural
analgesia vs general anesthesia and opioid use3. Indeed,
GI function may return 2-3 days earlier.
Thoracic analgesia has been advocated as a
means to reduce postoperative pain over intravenous
opioid use3. Mechanisms by which this technique may
promote GI activity include blockade of nociceptive
afferent nerves and thoracolumbar sympathetic
efferent nerve, unopposed parasympathetic efferent
nerves, a reduced need for parenteral narcotics,
increased GI blood flow and a systemic absorption of
local anesthetic4. However, not all procedures and/or
patients are amenable to regional techniques, whether
for the surgical procedure or for postoperative pain
management.
Surgical Technique
A meta-analysis of randomized clinical trials up
to 2002, reviewed 2,512 cases in 12 trials. Relative
improvements with laparoscopic techniques over open
procedures for colorectal resection showed significant
decrease in time to passage of flatus (34%), pain at
6 hours and 3 days (35% and 63%) and narcotic use
(37%) as well as earlier toleration of diet (24%)5.
A less invasive surgical technique reduces
the activation of inhibitory reflexes and local
inflammation6. As bowel manipulation is minimized,
the histogram count of infiltrating polymorphonuclear
lymphocytes is significantly reduced.
Opioid-Sparing Analgesia
The use of non-steroidal anti-inflammatory drugs
(NSAIDs) for pain relief may improve POI by reducing
the need for opioids by 20-30%7.
An additional positive effect may be related to an
anti-inflammatory effect on bowel motility. In several
studies, administration of ketorolac has been shown to
allow faster resolution of POI and decreased nausea
and vomiting and improved GI transit8,9. Potential side
effects related to coagulation problems may make these
agents relatively contraindicated in some surgeries.
161
Ketorolac 30 mg is equivalent to morphine 10 mg or
Demerol 100 mg.
Early Feeding
Several randomized clinical trials indicated
that early feeding is beneficial, putting into question
the common practice of withholding any intake until
the resolution of POI10. However, some studies show
equivocal results. Nevertheless, many surgeons
recommend that chewing gum during the perioperative
period will decrease the duration of POI. In theory,
early feeding should stimulate GI motility by eliciting
a reflex response and stimulation of hormonal factors.
The technique appears safe and is generally well
tolerated except in patients who are actively vomiting.
Preoperative Psychological Preparation
Many surgeons have claimed that POI may be
reduced or eliminated by advising patients that they
will not have any difficulties. The mechanism by
which suggestion would work is unknown. One study
found positive benefit in decreasing time to flatus and
hospital discharge11. However, results are not reliable.
Placement of a Nasogastric Tube
Placement of a nasogastric (NG) tube should
decompress the stomach and small bowel. While this
may relieve the symptoms of POI, there is no evidence
that it will decrease the duration.
A meta-analysis of 33 randomized trials (5240
patients) compared routine NG tube use at the end of
surgery (2628 patients) with selective or no NG tube use
(2612 patients). Patients who had no NG tube placement
had an earlier return of bowel function (p<0.00001),
and a decrease in pulmonary complications (p = 0.1)12.
Vomiting favored NG tube placement which improved
patient comfort. The study concluded that routine NG
tube placement achieved none of the intended goals
and should be replaced by selective use, such as when
a patient is actively vomiting.
Early Mobilization
Early mobilization – getting patients out of bed
and walking – may exert a mechanical stimulation
of intestinal function. However, the evidence does
M.E.J. ANESTH 20 (2), 2009
162
not show a significant change in the duration of POI,
although there is a decrease in other postoperative
complications such as pneumonia, deep venous
thrombosis and pressure sores12.
Fluid Restriction
Several studies have shown that restricting
intravenous fluids may be beneficial. Lobo et al
compared the standard administration of >31 water with
154 mmol sodium per day and restricted, <21 water
and 77 mmol sodium intake, after hemicolectomy.
There were significantly more complications in the
standard group. Both solid and liquid phase emptying
times were significantly reduced in the study group13. A
recent review emphasizes the need for fluid restriction
noting that failure to do so intraoperatively is associated
with pneumonia, cardiac complications, postoperative
blindness, coagulopathies, and increased cutaneous
edema among many other problems14.
Intravenous crystalloids remain in the
intravascular space for very short periods,
redistributing quickly to soft and damaged tissue and
dependent areas such as the gut. Edema in the gut
wall increases the inflammatory response and retards
forward movement.
Elizabeth AM Frost
While several RCTs have shown that fast-tracking
reduces the length of hospital stay and the duration of
bowel dysfunction compared to traditional care, the
problem of POI remains indication that additional
therapies might improve the quality of care and patient
satisfaction15.
Most surgical and terminal-care patients
require opioids for pain management. Opioids inhibit
propulsive motility and secretion, effects mediated
primarily by µ opioid receptor sites in the bowel. Both
naloxone and naltrexone reduce bowel dysfunction but
reverse analgesia. Naloxone is a competitive µ-opioid
receptor antagonist, which readily crosses the bloodbrain barrier when given intravenously. It reverses
the centrally mediated effects of opioids and may
precipitate opioid withdrawal. There are no current
data to show benefit in POI.
Ideally, POI therapy would be a peripheral
receptor antagonist that reverses GI effects without
compromising analgesia (Fig. 2).
Fig. 2
Opioid receptors are in both the gut and the brain. Antagonists
must not cross the blood
brain barrier if pain relief is to be maintained
Prokinetic Agents
Use of dopamine antagonist and cholinergic
agonist agents such as metoclopramide should
theoretically improve gut function. However,
most randomized clinical trials (RCT) suggest no
prophylactic or therapeutic benefit12. Indeed, side
effects of metoclopramide occurred in 15-20% of
patients and included drowsiness, dystonic reactions
and agitation, especially in younger patients. Cisapride,
a serotonin receptor agonist is possibly effective but
has been withdrawn from the Unites States market
because of cardiovascular side effects. Erythromycin
is a motilin agonist and again, two RCTs suggest no
significant change in the duration of POI.
Newer Approaches
The use of laparoscopic techniques, regional
anesthesia and NSAIDS’s, selective NG placement,
early ambulation and fluid restriction are referred to as
“fast-tracking”.
Reproduced courtesy of Adolor Corporation.
The US Food and Drug Administration has recently
approved two drugs that do this: methylnaltrexone and
alvimopan (Table2).
Both agents are peripherally acting µ opioid
receptor antagonists. Neither crosses the blood-brain
barrier, and both preserve pain relief. Time to recovery
of GI function was shown to be significantly decreased
with both drugs in multiple trials16,17,18.
Need for reinsertion of an NG tube postoperatively
163
Table 2
New Medications for Ileus
Alvimopan (Entereg)
Methylnaltrexone (Relistor)
Indications approved by the
FDA
Postoperative ileus
opioid-induced constipation in advanced
illness
Form
capsule
subcutaneous injection
Side effects
low blood-calcium levels, anemia and
gastrointestinal problems, including
constipation, dyspepsia (heartburn) and
flatulence (excess bowel gas)
abdominal pain, gas, nausea, dizziness
and diarrhea
was reduced by 50% with both alvimopan 6 mg and
12mg. Serious adverse events were reduced from 6.7%
to 1.8%19.
Prolonged hospital stay with alvimopan
decreased from 13.7% to 7% and readmission was also
reduced from 11.7% to 7.5%19. The time to toleration
of solid foods after methylnaltrexone was 100 hours
against 125 hours in the placebo group17. Similar
figures were obtained for alvimopan15,16. Reduction in
time to first bowel movement averaged 25 hours with
methylnaltrexone17. In several trials using alvimopan,
time reduction was about 50% from control15,16,18.
In all the studies of both drugs, the time to
discharge-eligibility was decreased by about 1 day over
control18. Pooled data of any morbidity for alvimopan
showed a decrease from 16% to 8%18.
However, based on one study, concerns were
raised about cardiovascular adverse events with
alvimopan. Reviewing 2610 patients in 8 trials the
incidence of myocardial infarction was 0.5% which
matched the control finding of 0.51%20. But one
study of 538 patients indicated 7 cases of myocardial
infarction against 0 in the control group.
The study protocol had called for alvimopan 0.5
mg bd, which was a much smaller dose than that used
therapeutically in the other trials. All cardiovascular
events occurred in patients with established disease or
at high risk. After this data became available, the FDA
reviewed a 12-month study of alvimopan in patients
treated with opioids for chronic pain. In the study, there
were more reports of myocardial infarction in patient
treated with the low dose of alvimopam, and imbalance
not observed in other studies of patients undergoing
bowel resection surgery who received alvimopam
12 mg twice daily for up to 7 days. The conclusion
was that a causal relation between alvimopan and
myocardial infarction has not been established.
Regarding other potential side effects, patients
with severe hepatic impairment may have a potential
for 10-fold higher plasma levels, although no studies
are available in this patient population. It is not
recommended for patients with end-stage renal disease.
While teratogenic effects in humans are unknown,
reproduction studies in pregnant rats and rabbits at
many multiples of human dosages have not revealed
any evidence of impaired fertility or fetal harm.
However, alvimopan and its metabolite have been
detected in the milk of lactating rats.
Alvimopan Approved for Short-Term Use
Alvimopan (Entereg®, Adolor/GlaxoSmithKline)
was approved by the FDA in May 2008 to accelerate
restoration of normal bowel function after bowelresection surgery. The recommended dose is one
12 mg capsule given 30 minutes to 5 hours prior to
surgery, followed by a 12 mg capsule twice daily for
up to 7 days but not to exceed 15 doses. The drug is
available for hospital use only with a Risk Evaluation
and Mitigation Strategy (REMS) and EASE program
(Entereg® Access Support and Education). Hospitals
must complete a registration process. The drug is
contraindicated in patients who have taken therapeutic
doses of opioids for more than 7 consecutive days
immediately prior to taking alvimopan. The program
is designed to maintain benefits associated with shortterm use only.
M.E.J. ANESTH 20 (2), 2009
164
Elizabeth AM Frost
Methylnaltrexone Approved for Palliative
Care
Methylnaltrexone (Relistor , Wyeth/Progenics),
the other peripherally acting µ opioid antagonism
was approved by the FDA in April 2008 for the
treatment of opioid-induced constipation in patients
with advanced illness who are receiving palliative
care. It is administered as a subcutaneous injection.
The recommended starting schedule is 0.15 mg/kg
on alternate days, not to exceed 1 dose in a 24 hours
period20. The drug is packaged in a vial as 12 mg/0.6
ml. It should not be given if there is any mechanical
bowel obstruction and has not been studied in patients
with peritoneal catheters or in the pediatric population.
The most common side effects include abdominal pain,
flatulence and nausea.
®
Chronic Illness and Methylnaltrexone
Thomas et al22 enrolled a total of 133 patients
who had received opioids for 2 or more weeks and
who had received stable doses of opioids and laxatives
for 3 or more days without relief of opioid-induced
constipation.
The patients were randomly assigned to receive
subcutaneous methylnaltrexone (at a dose of 0.15 mg
per kilogram of body weight) or placebo every other
day for 2 weeks. Co-primary outcomes were laxation
(defecation) within 4 hours after the first dose of the
study drug and laxation within 4 hours after two or
more of the first four doses. Patients who completed
this phase were eligible to enter a 3-month, open-label
extension trial.
They found in the methylnaltrexone group that
48% of patients had laxation within 4 hours after the
first study dose, as compared with 15% in the placebo
group, and 52% had laxation without the use of a
rescue laxative within 4 hours after two or more of the
first four doses, as compared with 8% in the placebo
group (p < 0.001 for both comparisons).
The response rate remained consistent throughout
the extension trial. The median time to laxation was
significantly shorter in the methylnaltrexone group than
in the placebo group. Evidence of withdrawal mediated
by central nervous system opioid receptors or changes
in pain scores was not observed. Abdominal pain and
flatulence were the most common adverse events.
The authors concluded that subcutaneous
methylnaltrexone rapidly induced laxation in patients
with advanced illness and opioid-induced constipation.
Treatment did not appear to affect central analgesia or
precipitate opioid withdrawal.
Economic Considerations with POI
POI is the most common reason for delayed
discharge after abdominal surgery. Increased health-care
costs in the United States related to this complication
are estimated to reach 1$ billion annually because of
increased need for supplies, nursing care and laboratory
testing. The possible benefits of adding a peripherally
acting µ opioid receptor antagonist such as alvimopan
to a fast tracking model are shortened hospital stay,
reduced use of resources, fewer complications, fewer
readmissions and improved patient satisfaction18.
Conclusion
POI affects between 4-20% of abdominal
surgical patients. Constipation is a major problem for
the terminally ill who are maintained on opioids. In
both situations there is a detrimental effect on clinical
outcomes and cost of care. Accelerating recovery and
even maintaining GI function enhances patient comfort
and improves outcome. Treatment options include both
pharmacologic and non pharmacologic approaches. The
anesthesiologist can make an important contribution to
improved care.
165
References
1. Baig MK, Wexner SD: Postoperative ileus: A review Dis Colon
Rectum; 2004; 47:516-26.
2. Health Care Financing Administration: Medicare, 1999-2000.
Federal Registry. Available at http://www.gpoaccess.gov/fr
3. Moraca MJ, Sheldon dG, Thirlby rC: Te role of epidural anesthesia
and analgesia in surgical practice. Ann Surg; 2003; 238:663-73.
4. Steinbrook RA: Epidural anesthesia and gastrointestinal motility.
Anesth Analg; 1998, 86:837-44.
5. Abraham NS, Young JM, Solomon MJ: Meta-analysis of short term
outcomes after laparoscopic resection for colorectal cancer. Br J
Surg; 2004, 91:1111-24.
6. Kalff JC, Schraut WH, Simmons RL, et al: Surgical manipulation
of the gut elicits an intestinal muscularis inflammatory response
resulting in post surgical ileus. Ann Surg; 1998, 228:652-63.
7. Gillis JC, Brogden RN Ketorolac: A reappraisal of its
pharmacodynamic and pharmacokinetic and therapeutic uses in
patient management. Drugs; 1997:53(1):139-88.
8. Kelley MC, Hocking MP, Marchand SD et al: Ketorolac prevents
postoperative small intestinal ileus in rats. Am J Surg; 1993, 165:10711.
9. De Winter BY, Boeckxstaens GE, De Man JG, et al: Differential
effects of indomethacin and ketorolac on postoperative ileus in rats.
Eur J Pharm; 1998, 344:71-6.
10.Holte K, Kehlet H: Postoperative ileus: a preventable event. Br J
Surg; 2000, 87:1480-93.
11.Behm B, Stollman N: Postoperative ileus: etiologies and
interventions. Clin Gastroenterol Hepatol; 2003, 171-80.
12.Nelson R, et al: Cochrane Data Base. Syst Rev; 2007,
3:CD004929.
13.Lobo DN, Bostock KA, Neal KR, et al: Effect of salt and water
balance in recovery of gastrointestinal function after elective colonic
resection: a randomized clinical trial. Lancet; 2002, 359:1812-8.
14.Chappell D, Jacob M, Hofman-Kiefer K, et al: A rational approach
to perioperative fluid management. Anesthesiology; 2008, 109:72340.
15.Delaney CP, Zutshi M, Senagore AJ, et al: Prospective, randomized,
controlled trial between a pathway of controlled rehabilitation with
early ambulation and diet and traditional postoperative care after
laparotomy and intestinal resection. Dis Colon Rectum; 2003,
46:851-9.
16.Wolff BG, Michelassi F, Gerkin TM, et al: Alvimopan. A novel
peripherally acting mu opioid antagonist: results of a multicenter,
randomized, double-blind, placebo-controlled, phase 111 trial of
major abdominal surgery and postoperative ileus. Ann Surg; 2004,
240:728-35.
17.Viscusi ER, Goldstein S, Witkowski T, et al: Alvimopan, a
peripherally acting mu-opioid receptor antagonist, compared with
placebo in postoperative ileus after major abdominal surgery: results
of a randomized, double blind, controlled study. Surg Endos; 2006,
20:64-70.
18.Leslie JB: Alvimopan, a peripherally acting mu-opioid receptor
antagonist. Drugs Today; 2007, 43:611-25.
19.Delaney CP, Wolff BG, Viscusi ER, et al: Alvimopan for
postoperative ileus following bowel resection: a pooled analysis of
phase 111 studies. Ann Surg; 2007:245:355-53.
20.FDA Web site: www.FDA.gov/ohrms/dockets/ac/cder08.html#gdac
21.FDA Web site: www.FDA.gov/bbs/topics/NEWS/2008/NEW01826.
html
22.Thomas J, Karver S, Cooney GA, et al: Methylnaltrexone for
Opioid-Induced Constipation in Advanced Illness. NEJM; 2008,
358:2332-2343.
M.E.J. ANESTH 20 (2), 2009
CURRENT PERIOPERATIVE MANAGEMENT
OF THE PATIENT WITH HIV
- Literature Review -
Amir Baluch , Hiamine Maass**, Cynthia Rivera***,
Abhinav Gautam*, Alan Kaye****
and E lizabeth A.M. F rost *****
*
Introduction
Human immunodeficiency virus (HIV) is a member of the lentivirus subgroup of retroviruses,
and has been shown to be the cause of acquired immunodeficiency syndrome (AIDS). It is believed
that HIV-1 evolved with chimpanzees and crossed over to human beings1. Another type of the HIV
virus, HIV-2, originated from the simian immunodeficiency virus (SIV) of Cercocebus atys in West
Africa, where the virus is endemic2. HIV entered the United States in the late 1970s and was first
described in 19813.
Epidemiology
Currently there are close to 1 million people infected with HIV in the United States, and
there has been a steady increase in the number of infected individuals since 20014. In 2003, there
were an estimated 43,171 new cases of AIDS diagnosed in this country. Additionally, there was an
estimated 18,017 deaths in 2003 due to AIDS, resulting in a cumulative estimated number of deaths
in the United States AIDS population of 524,0604. In 2006 the worldwide number of deaths was 2.9
million and the total number of individuals living with HIV/AIDS is 39.5 million. The number of
AIDS related deaths is decreasing in the United States due to antiretroviral therapy5.
HIV transmission is mediated by sexual contact or through infected blood. Neonates may be
exposed directly at the time of delivery, by breast-feeding, or by transplacental spread6. Currently,
the 3 most common routes of transmission are male-to-male sexual contact, heterosexual contact,
and intravenous drug use4.
*
MD, Anesthesia Resident, Jackson Memorial Hospital/University of Miami, Miami, Florida, USA.
** Research Associate, Louisiana State University Health Science Center, New Orleans, Louisiana, USA.
*** MD, Fellow, Dept. of Infectious Disease, Jackson Memorial Hospital/University of Miami, Miami, Florida, USA.
****MD/PhD/DABPM, Professor and Chairman, Department of Anesthesiology, Louisiana State University Health Science
Center, New Orleans, Louisiana, USA.
*****MD, Clinical Professor of Anesthesia, Mount Sinai School of Medicine, New York, NY.
Corresponding author: Dr. Amir R. Baluch, MD, 1504 Bay Road # 1010, Miami Beach, FL 33139,USA.
E-mail [email protected]
investigative products in this lesson.
167
M.E.J. ANESTH 20 (2), 2009
168
Amir Baluch et. al
Pathophysiology
The HIV virus is composed of single-stranded
RNA, which contains a variety of genes including gag,
pol, vif, vpr, vpu, env, tat, rev, and nef. Long terminal
repeats (LTR) flank the RNA sequence at both ends6.
The pol gene encodes reverse transcriptase; an enzyme
necessary to copy the viral RNA to double-stranded
DNA once the viral genome enters the host cell3, and
integrase, an enzyme necessary for incorporation of
the newly copied DNA into the host cell genome. The
HIV virus is covered by a lipid bilayer that contains the
envelope proteins gp120 and gp41 (Fig. 1)
Fig. 1
Pathophysiology of HIV
HIV shows marked tropism for CD4+ helper
T cells, due to the CD4 molecule’s high affinity
receptor for the viral gp120 glycoprotein2; however,
the CD4 molecule is not sufficient for infection. Two
coreceptors have been identified as cellular targets for
viral HIV. These coreceptors are CXCR4 and CCR57.
Macrophages and monocytes predominately carry
CCR5 receptors, while T-cells carry predominately
CXCR4 receptors. In the early stages of infection, the
CCR5 dependent HIV viral particles predominate. As
the disease progresses, a rapid decline in T-cell counts
is associated with a switch from CCR5 tropic viruses
to CXCR4 or CXCR4/CCR5 viruses7.
After the HIV viral gp120 glycoprotein binds
the cell CD4 receptor, a conformational change of
the gp120 glycoprotein occurs. The alteration allows
the gp120 glycoprotein to bind the CCR5 or CXCR4
coreceptor. The other envelope glycoprotein, gp41, can
now penetrate the host cell membrane6. As the HIV virus
undergoes membrane fusion with the host cell, copies
of its RNA genome are released into the cytoplasm of
the host cell8. Once the single-stranded RNA of the
HIV virus is inside the host cell, reverse transcriptase
can copy the viral RNA into double-stranded cDNA
to be inserted into the host genome using integrase9.
After insertion into the host cell’s genome, HIV viral
mRNA is transcribed using the host’s own RNA
polymerase. This viral mRNA is then translated into
many large polyproteins, which are further cleaved by
a combination of viral and host cell proteases. These
polyproteins are packaged into immature virions in
the cytoplasm of the cell along with viral protease. As
the immature virions bud from the cell’s membrane
using lipid raft regions of the host cell’s membrane10,
the viral protease cleaves the polyproteins forming the
mature HIV particle.
HIV infects CD4+ helper T cells, eventually
killing them and suppressing cell-mediated immunity.
The host becomes vulnerable to a wide variety of
opportunistic infections and is predisposed to certain
cancers. There are several ways in which HIV causes
the net decrease in T-cells. The most common way is
by viral replication and cell lysis, and the effects of
a productive infection (i.e. killing by HIV-specific
cytotoxic CD8+ lymphocytes)6. Persistent T-cell
activation can also cause depletion of the naïve T-cell
pool, leading to an overall decrease in CD4+ T-cell
numbers11. Yet another way HIV generates a net
decrease in T-cells is by reducing production of CD4+
T-cells, a theory supported by studies demonstrating
that the telomeres of CD4+ cells in HIV-infected cells
of long-term HIV survivors are not shorter than those
of uninfected CD4+ cells13.
One of the first targets of the HIV virus after
infection due to sexual contact is the dendritic cell,
which express CCR5 receptors. After becoming
infected, these cells present the virus to CD4+ cells
lymphocytes. Within two days of infection, virus
can be detected in the draining internal iliac lymph
nodes, and within five days after infection HIV can be
cultured from plasma12. Ultimately, HIV disseminates
throughout the body including the central nervous
system where it can hide or remain dormant for
years.
During the initial infection with HIV, the plasma
viral load is extremely high. This initial period is
referred to as the acute stage, and usually begins 2 to
CURRENT PERIOPERATIVE MANAGEMENT OF THE PATIENT WITH HIV
4 weeks after infection. The cell-mediated arm of the
immune system helps control the infection, and thus the
viral load declines. This period of decreased HIV viral
load is known as the latency period, and the patient is
asymptomatic during this time. The late stage of HIV
infection is known as acquired immunodeficiency
syndrome (AIDS), and has an average course of about
10 years13. Due to the high viral loads, patients in the
acute stage and late stage are the most infectious
Acquired immunodeficiency syndrome is
defined as a CD4+ T-cell count below 200 cells/mm3,
or the development of an AIDS-defining condition.
Such conditions include candidiasis, invasive
cervical cancer, coccidioidomycosis, cryptococcosis,
cryptosporidiosis, cytomegalovirus disease, HIVrelated encephalopathy, severe herpes simplex infection,
histoplasmosis, isosporiasis, Kaposi’s sarcoma, certain
types of lymphoma, mycobacterium avium complex,
Pneumocystis carinii pneumonia, recurrent pneumonia,
progressive multifocal leukoencephalopathy, recurrent
salmonella septicemia, toxoplasmosis of the brain,
tuberculosis, and wasting syndrome14. (Table 1)
Pharmacology
Several therapeutic regimes are available for the
treatment of HIV infection.
169
Nucleoside reverse transcriptase inhibitors
(NRTIs)
NRTIs remain the most commonly prescribed
ARVs and are virtually always included in the initial
treatment regimen. NRTIs are incorporated into
the viral DNA, preventing reverse transcription
and therefore inhibiting viral DNA synthesis. Viral
replication is prematurely terminated and infection
of new target cells is reduced. NRTIs are specific
inhibitors of HIV reverse transcriptase, but also inhibit
human mitochondrial DNA polymerase γ to varying
degrees. Commonly used NRTIs are zidovudine,
lamivudine, emtricitabine, and abacavir. Side effects
commonly reported with zidovudine treatment include
headache, insomnia, nausea, and vomiting. Prolonged
therapy can lead to neuropathy, malaise, myalgia and
myopathy with increased creatinine-phosphokinase,
and pancytopenia. Peripheral neuropathy is the most
common side effect of zalcitabine. It correlates with
the severity of HIV infection and may affect 30% of
patients treated15. Lamivudine is the least neurotoxic
of the currently used nucleoside analogues. It may
exacerbate preexisting neuropathy16. However,
combined antiretroviral therapy was shown to improve
HIV-related peripheral neuropathy17. Peripheral
neuropathy generally reverses on cessation of therapy.
Table 1
Diagnostic criteria of AIDS in the patient with HIV
CD4+ T-Lymphocyte count <200 cells/µl
Multiple or recurrent bacterial infections
Candida of the bronchi, trachea, lungs, esophagus
Burkitt’s Lymphoma
Cervical cancer, invasive
Immunoblastic lymphoma
Dissiminated or extrapulmonary Coccidiodomycosis
Dissiminated or extrapulmonary Mycobacterium avium complex
or kansasii
Extrapulmonary Cryptococcosis
Mycobacterium tuberculosis
Chronic intestinal Cryptosporidiosis lasting greater than 1 month
Pulmonary or extrapulmonary Mycobacterium, any other
species
Cytomegalovirus (CMV) outside of liver, spleen, lymph nodes
Pneumocystis carinii pneumonia (PCP)
CMV retinitis or CMV associated loss of vision
Recurrent Pneumonia
Herpes simplex virus with chronic ulcers (>1 month), bronchitis, Progressive multifocal leukoencephalopathy
pneumonitis, esophagitis
HIV-related encephalopathy
Sepsis with Recurrent Salmonella
Dissiminated or extrapulmonary Histoplasmosis
Toxoplasmosis of the brain
Chronic intestinal Isophoriasis lasting greater than 1 month
Wasting syndrome due to HIV
CDC 1993 revised classification system for HIV infection (effective after January 1993). MMWR 1992; 41:RR-17.
M.E.J. ANESTH 20 (2), 2009
170
Non-Nucleoside reverse transcriptase
inhibitors (NNRTIs)
NNRTIs act at the same step in the HIV life
cycle as NRTIs, but do not require intracellular
phosphorylation and thus do not inhibit human
DNA polymerases. Nevirapine strongly induces
CYP450 3A4 isoenzymes, while efavirenz is a mixed
inducer/inhibitor of the same enzyme. The NNRTIs
most commonly used are nevirapine, delavirdine, and
efavirenz. Their major side effect is skin rash, including
Stevens- Johnson’s syndrome. Nevirapine causes
cytochrome P450 enzyme induction (CYP3 A3/4)
and may decrease serum levels of some anesthetic or
sedative drugs (i.e., midazolam, fentanyl)18.
Protease inhibitors (PIs)
PIs function by preventing cleavage of viral
precursor proteins into the subunits required for
the formation of new virions. These result in the
cessation of new virus production from currently
infected cells. The most commonly used PIs are
saquinavir, ritonavir, indinavir, and nelfinavir. Side
effects are gastrointestinal symptoms, hyperglycemia,
peripheral neuropathy, increased liver enzymes,
and hypertriglyceridemia19. Efavirenz is a potent
teratogenic drug that should be avoided during the first
trimester of pregnancy20.. Indinavir may be associated
with mild hyperbilirubinemia, hematuria, and renal
failure resulting from obstructive uropathy. The PIs
are metabolized by the cytochrome P450 isoenzyme
cytochrome P3A4 (CYP3A4). They competitively
inhibit the enzyme and may increase the effects of drugs
metabolized by cytochrome P450 such as sevoflurane,
desflurane, and propofol. Therefore, anesthetic drugs
which are metabolized by cytochrome P450 should
be titrated carefully18. Ritonavir is the most potent
inhibitor of CYP3A4 and CYP2D6 and is a less potent
inhibitor of CYP2C9/1021. Fentanyl, a synthetic opioid
analgesic, is metabolized mainly by CYP3A421 and to
a lesser extent by other CYPs22.
Fusion Inhibitors (FIs)
Fusion (entry) inhibitors such as enfuvirtide
represent a new class of antiretrovirals that effectively
block viral entry into the cell and have no cross-resistance
to other currently FDA-approved antiretroviral agents.
Amir Baluch et. al
FIs must be used in conjunction with other retroviral
regimens. The main side effect encountered is injection
site reactions. Post injection many patients complain
of pain, induration and erythema.
Side Effects and Drug Interaction with
Anesthesia
Prior to administration of any anesthetic the
anesthesiologist should be aware to the possible
interaction of antiretroviral drugs with the anesthetics
and/or toxic side effects. The presence of a myopathy or
neuropathy may alter the anesthetic technique. Anemia
and thrombocytopenia are major toxic side effects
of zidovudine. PIs can affect glucose metabolism.
Foscarnet and PIs can cause renal toxicity.
Foscarnet can also alter calcium and magnesium
levels by chelating divalent metal ions thereby
increasing serum calcium levels. Some side effects
from other agents include ventricular arrhythmias
(IV pentamidine) and bronchospasm (aerosolized
pentamidine). Nevirapine is an inducer of CYP450
and therefore increased doses of anesthetic drugs
may be required in patients receiving the drug18. PIs,
such as ritonavir, are inhibitors of CYP450, which
impair the metabolism of multiple anesthetics and
analgesics, such as midazolam and fentanyl, and
cardiac drugs, such as amiodarone and quinidine21.
Etomidate, atracurium, remifentanil and desflurane are
not dependent on CYP450 hepatic metabolism, and
therefore, are preferable drugs.
Due to the myriad of drug interactions, the
anesthesiologist may consider regional anesthesia as
the mode of anesthetic delivery. Regional anesthesia
has an advantage because it does not interfere
with antiretroviral drugs or the immune system.
Contraindications to regional anesthesia (apart from
patient acceptance and the surgical site) include sepsis,
platelet abnormalities, and seeding HIV to the CNS
via a bloody tap. The presence of neuropathy may
reduce the appeal of regional anesthesia but there is
no data suggesting contraindication. In a review of
96 HIV positive parturients, of whom 36 delivered
under regional anesthesia, the advantages of regional
anesthesia were confirmed23. In 2002 the effect of spinal
anesthesia was studied in 45 HIV-treated parturients
who underwent cesarean delivery25. No perioperative
complications or changes to viral load were noted.
Perioperatively, magnetic resonance imaging
(MRI) studies can be useful although not commonly
done. Images of the spinal cord in 55 symptomatic HIV
patients showed neurologic involvement of the spinal
cord in 49 patients, mostly of infectious origin24. Many
compromised HIV patients are drug abusers, diabetics,
postorgan transplantation recipients, and on long-term
steroid treatment and develop spinal infections. They
are often diagnosed too late, mostly presenting with
back pain or other neurologic signs or symptoms25.
Prolonged epidural catheterization in such severely
compromised patients may be contraindicated26.
However, a series of 350 cancer patients who had
prolonged epidural catheterization and were monitored
closely for possible infection and promptly treated had
no adverse sequelae27.
Common adverse effects of drug therapy
Mitochondrial toxicity can manifest as
hyperlactatemia,
hepatic
steatosis,
peripheral
neuropathy, myopathy, and lipodystrophy. Although
the exact pathogenesis in the HIV infected patient is
debatable, the most likely culprit is NRTIs. NRTIs cause
mitochondrial toxicity by inhibiting mitochondrial DNA
polymerase γ. Mitochondrial toxicity is less common
now, as the newer NRTIs (lamivudine, tenofovir,
and abacavir) have low affinity for mitochondrial
DNA polymerase γ compared with “older” NRTIs
(didanosine, stavudine [d4T], zalcitabine, often referred
to as “D-drugs”).
Dyslipidemia can result from antiretroviral (ARV)
administration. Regular monitoring of cholesterol and
triglycerides is required and lipid-lowering agents
are often indicated. The metabolic syndrome, type
2 diabetes and vascular events are also complications
of ARVs. An association between PI exposure and risk
for increased cardiovascular events is well established.
The link (although weaker) has also been demonstrated
with NRTIs and NNRTIs. New ARV drugs with
less effect on lipids and insulin resistance are under
development.
Clinical Presentation
Initially, the acute stage of HIV infection can
be subclinical or present with a mononucleosis-like
prodrome of fever, sore throat, lethargy, headache,
171
nausea, vomiting, diarrhea, rash, lymphadenopathy,
aseptic meningitis, and/or leukopenia. The number of
CD4+ cells is within normal range, however, this acute
stage lasts approximately 7 to 10 days. Even though
the majority of HIV infections are symptomatic, many
cases are initially misdiagnosed due to the similar
prodrome of other viral illnesses, and the lack of
detectable HIV-1 antibodies. It is essential to obtain a
sexual history for high risk behavior of sexually active
people who present with symptoms of viral meningitis,
lymphadenopathy, sore throat, or fever28. Death most
often results from opportunistic infections, cancer, or
wasting. These opportunistic infections occur due to the
decrease in the cell-mediated immunity of the patient.
Diagnosis and Differential Diagnosis
The diagnosis of acute HIV-1 infection can
be made by detection of plasma HIV-1 RNA in the
plasma, in the absence of HIV antibodies. Most
assays for HIV-1 RNA have sensitivities near 100%,
however, approximately 2-5% of tests resulted in false
positives29. The false-positives yielded viral loads
much smaller than those normally seen during acute
infections. Upon retesting the same samples, the truenegative result was obtained29. Detection of p24 has a
much lower sensitivity, and lower specificity. A CD4+
T-cell count should be obtained, along with a complete
blood count, chemistry profile, transaminase levels,
BUN and creatinine30.
Infectious mononucleosis is the most important
illness in the differential diagnosis for HIV infection.
Other diseases in the differential diagnosis for HIV
infection include hepatitis, syphilis, influenza, and side
effects of various medications.
Antiretroviral Chemotherapy
Use of current antiretroviral agents can slow
the progression of HIV infection to AIDS (Table 2).
Treatment should begin if the patient has a history of
an AIDS-defining illness or if the patient has severe
symptoms of an HIV infection irregardless of the
CD4+ T-cell count. The clinician should also initiate
treatment if the CD4+ T-cell count is less than 200
cells/mm3. Treatment should be offered to patients
with CD4+ cell counts of 201 to 350 cells/mm3. If a
patient has a cell count greater than 350 cells/mm3, and
M.E.J. ANESTH 20 (2), 2009
172
Amir Baluch et. al
a plasma HIV RNA level greater than 100,000 copies/
ml, the decision to treat is left to the discretion of the
clinician. For patients, with a CD4+ cell count greater
than 350 cells/mm3, and a plasma HIV RNA level less
than 100,000 copies/ml, therapy should be deferred30.
Table 2
Initiation of Antiretroviral Chemotherapy
Patient Indications
Treatment Option
History of AIDS-defining illness or
severe symptoms of HIV infection
irregardless of CD4+ T-cell count
Initiate Treatment
CD4+ T-cell count of 201-350 cells/
mm3
Offer treatment to
patient
CD4+ T-cell count > 350 cells/mm3 and Clinician’s
plasma HIV RNA > 100,000 copies/ml discretion
CD4+ T-cell count > 350 cells/mm3 and Defer therapy
plasma HIV RNA < 100,000 copies/ml
Opportunistic Infections
Opportunistic infections are a significant source
of morbidity and mortality in patients infected with
HIV. The use of antiretroviral therapy has helped
in preventing and treating opportunistic infections.
Antiretroviral therapy also increases the cell-mediated
immune response, which is important for vaccinations.
Vaccines elicit better immunologic responses with
higher CD4+ T-cell counts. Live attenuated vaccines
should not be given to HIV infected patients since this
immunocompromised population may not respond as
well to the vaccine and may have a greater chance of
suffering from side effects of the vaccination31.
Early diagnosis and treatment of Mycobacterium
tuberculosis is critical in an immunosuppressed
patient to prevent acceleration of the disease. Patients
with positive PPD skin tests can be treated for six
months with isoniazid or rifampin. An alternate initial
treatment rifabutin, pyrazinamide, or ethambutol given
for 2 months followed by 4 months of treatment with
isoniazid or rifampin is also acceptable32.
A very widespread and common problem for
immunosuppressed patients is Pneumocystis carinii
pneumonia. Trimethoprim-sulfamethoxazole is the
first line treatment33 and should be administered as
prophylaxis if CD4+ T-cell counts decrease to less than
200 cells/mm3. Patients with a history of Pneumocystis
carinii pneumonia should be given trimethoprim-
sulfamethoxazole for life unless antiretroviral therapy
restores immune system function33.
Toxoplasma gondii encephalitis is an opportunistic
infection with the greatest risk for patients with a CD4+
cell count less than 50 cells/mm334 . The drug of choice
is a combination of pyrimethamine, sulfadiazine, and
leucovorin.
Perioperative Anesthetic Management
The risk of contracting HIV from percutaneous
exposure with an instrument infected with HIV is
approximately 0.3%; however this risk increases
with a rise in severity of the injury beyond a simple
needlestick31. In order to minimize the risk to health
care providers, universal precautions must be followed
(Table 3). These precautions must be used for all
patients:
Table 3
General Precautions for Treating HIV-infected Patients
Wear gloves
Health care workers with open
lesions should avoid direct
patient contact
Use caution when
Use eye shields when chance
handling sharp objects of blood or body fluid
exposure to the eye
Do not recap needles
and dispose of used
needles immediately
in appropriate
containers
Use appropriate equipment for
cardiopulmonary resuscitation
to prevent mouth-to-mouth
resuscitation
1) Health care providers should wear gloves and
be cautious when handling sharp objects,
2) Needles should not be recapped, and
must be disposed of in the appropriate containers
immediately35,
3) Eye shields should be used if chance of blood/
body fluid contact with the eye exists,
4) Health care workers with open lesions should
avoid direct patient care,
5) Use equipment such as an ambu bag for
cardiopulmonary resuscitation to prevent mouth-tomouth resuscitation31.
In the event of accidental exposure, the exposed
health care should be evaluated within hours and not
days and should be tested for HIV at baseline36. The side
effects of the post exposure prophylactic medications
should be weighed against the likely risk of exposure,
and patient permission to treat should be obtained.
Post exposure prophylaxis should be initiated as soon
as possible following an exposure. Currently, most
post-exposure prophylaxis regimens involve a two
drug combination; the most common regimen involves
the use of zidovudine and lamivudine36. Appropriate
antiretroviral prophylaxis is outlined in )Table 4(.
173
Fig. 1
Plasma concentrations of fentanyl after an intravenous dose
of 5 μg/kg fentanyl following pretreatment with oral placebo
(left) or ritonavir (right) in 11 healthy volunteers. (Reprinted
from Olkkola KT, Palkama VJ, Neuvonen PJ. Ritonavir’s role
in reducing fentanyl clearance and prolonging its half-life.
Anesthesiology 1999;91:681–5; with permission.)
Table 4
Chemoprophylaxis of Percutaneous Exposures to HIV-1Infected Materials (adapted from Schooley RT. Acquired
immunodeficiency syndrome. Sci Am Med 1998;1-14)
Percutaneous Exposure
Source Material
1. Blood
Highest risk
Antiretroviral
Prophylaxis
Antiretroviral
Regimen
Recommended
Increased risk
Recommended
No increased risk
Offer
AZT plus
lamivudine plus
indinavir
AZT plus
lamivudine with or
without indinavir
AZT plus
lamivudine
AZT plus
lamivudine
2. Fluid containing
Offer
visible blood or
potentially infections
fluid or tissue
3. Other body fluids Do not offer
(urine, saliva)
Mucomembranous Exposure
Source Material
Antiretroviral
Prophylaxis
1. Blood
Offer
2. Fluid containing
Offer
visible blood or
fluid or tissue
(urine, saliva)
Skin exposure (increased risk)*
Source Material
Antiretroviral
Prophylaxis
1. Blood
Offer
Antiretroviral
Regimen
AZT plus
lamivudine with or
without indinavir
AZT plus
lamivudine with or
without indinavir
Antiretroviral
Regimen
AZT plus
lamivudine with or
without indinavir
AZT plus
lamivudine with or
without indinavir
Offer
2. Fluid containing
visible blood or
fluid or tissue
(urine, saliva)
AZT - zidovudine; CSF -cerebrospinal fluid
* Risk is considered increased: exposure to high titers of HIV-1,
prolonged contact, extensive area, an area of comprimised skin
integrity. For skin exposure without increased risk, the risk of
drug toxicity outweighs the potential benefits.
Preoperative assessment of the patient should
include a thorough history, review of medications as
well as an accurate CD4+ T-cell count. Patients with
high T-cell counts (500-700 CD4+ cells/mm3) are
less likely to have complications and are usually not
on antiretroviral medications3. Patients with CD4+
cell counts less than 200 should have renal and liver
function tests, blood counts, and clotting function tests
documented. An electrocardiogram, chest radiography,
and arterial blood gas may also be performed as
these patients are at increased risk for cardiovascular
complications3.
HIV is a systemic disease with multiorgan
manifestations.
The
pulmonary,
neurologic,
cardiovascular, and hematological manifestations of
HIV are of particular interest to the anesthesiologist3.
Pneumocystis carinii, Mycobacterium tuberculosis,
other bacteria, viral infections and fungal infections
like aspergillosis and candidiasis can serve as potential
pulmonary complications associated with anesthesia.
These infections have the potential for impairing
oxygenation. Care must be taken when placing tracheal
M.E.J. ANESTH 20 (2), 2009
174
tubes, to avoid risk of introducing an opportunistic
infection. AIDS patients may be transported with
masks if the mask were to decrease the likelihood of
contracting an opportunistic infection31. The anesthetic
equipment should be treated as a potential source of
infection, thus disposable anesthetic delivery circuits
with bacterial filters should be considered. Both the
use of masks during transport and disposable anesthetic
circuits have been used in some institutions31.
There are several neurological complications that
must be considered when treating a patient infected
with HIV. Myelopathies, Guillain-Barre syndrome,
peripheral neuropathies, brachial neuritis, and cauda
equina syndrome are associated with the acute stage
of HIV infection37. In the later stages of HIV infection,
neurological complications from opportunistic
infections can occur. HIV-associated dementia (HAD)
is another neurological complication. HAD can be
controlled with antiretroviral therapy; however a less
severe form of HAD can still exist38.
The general side effects associated with
antiretroviral medications such as hyperglycemia,
hyperlipidemia, and coronary arteriosclerosis as well
as the increase in life expectancy of HIV infected
individuals contributes to the increase in cardiovascular
complications of these patients39. Protease inhibitors
are associated with the dyslipidemias associated with
antiretroviral therapies, putting patients at risk for
future myocardial infections at a relatively young
age3.
Other cardiovascular complications associated
with HIV infection include cardiomyopathy, left
ventricular hypertrophy, myocarditis, pulmonary
hypertension, pericardial effusion, endocarditis, and
malignancy40. These complications can be due to the
infection, immunosuppression, or the drug therapy.
Myocarditis is a significant cause of death in adults
under the age of 40, and can range in severity from
asymptomatic to congestive heart failure41. The
recommended therapy for myocarditis is supportive
care. In the face of congestive heart failure, ionotropes,
diuretics, ACE inhibitors, nitroglycerin, nitroprusside,
or ventricular assist devices may be used31.
HIV can have hematological complications such
as thrombocytopenia, leucopenia, anemia, and bone
marrow suppression3. Although the thrombocytopenia
Amir Baluch et. al
is generally not considered to be clinically important,
it can worsen as the disease progresses3. Bone marrow
suppression is a reversible side effect of some of the
antiretroviral medications.
As mentioned earlier, there are significant
side effects and drug interactions associated with
antiretroviral therapy. Protease inhibitors, such as
lopinavir and ritonavir, cause various dyslipidemias,
increase serum aminotransferases, glucose intolerance,
and inhibit cytochrome P-450 (CYP) 3A3. Due to this
inhibition of the cytochrome enzyme, ritonavir has
been shown to reduce the clearance of fentanyl19. Thus
respiratory monitoring needs to be maintained for a
longer period and dosages of fentanyl should be adjusted
accordingly. Benzodiazepines and other opioids must
be used with caution again due to the inhibition of
cytochrome enzymes. A list of all drugs used by the
patient, as well as laboratory tests, questioning the
patient about side effects, and consultation with the
patient’s primary care provider must be obtained3.
Despite theoretical concerns of general anesthesia,
it is not associated with a significant incidence of
undesirable outcomes. Some transient immunologic
changes have been noted, but appear to be clinically
insignificant. An underlying pulmonary disease,
however, is more important. A patient with repeated P.
carinii infections, for example, may have pulmonary
damage and in those cases it may be sensible to avoid
endotracheal intubation. In these cases, regional
anesthesia presents as a favorable option, although
this consideration may apply to any patient with lung
damage3.
The appropriate use of regional anesthesia, on the
other hand, has been debated more frequently, as there
have been reports of adverse outcomes3,42. Concerns of
regional anesthesia centered on the safety of spinal and
epidural procedures, with fear of an extension of the
HIV infection into the CNS. However, CNS infection
is an early manifestation of the disease, and a failure
to culture HIV in the CSF is probably due to sampling
error43. Furthermore, Hughes et al. have demonstrated
the efficacy and safety of regional anesthesia44. In fact,
regional anesthesia for cesarean sections as well as
other surgical procedures may prove beneficial. The
regional approach has been associated with a decreased
requirement of parenteral opioids, thus the possible
side effects cause by a protease inhibitor’s effect on
drug metabolism may be curtailed3.
Sepsis and platelet abnormalities are
contraindications for regional anesthetics. Furthermore,
the presence of neuropathy secondary to HAART
therapy may diminish the appeal of regional anesthesia
but currently there are no data to contradict its use.
In fact, in a review of 96 HIV positive parturients,
of whom 36 delivered under regional anesthesia,
none of the women developed neurological sequelae,
suggesting that choice of anesthesia should be based
on the usual obstetric and clinical considerations.
Additionally, the effect of spinal anesthesia was
studied in 45 HIV-treated parturients who underwent
cesarean delivery, with outcome measures including
intraoperative blood pressure, heart rate, blood loss, and
ephedrine requirements, and postoperative infective
complications, blood transfusion, changes in blood
HIV-1 viral load and lymphocyte subsets, and time to
hospital discharge. The researchers found no difference
in hemodynamics or postoperative complications when
compared to controls45.
Although there may be theoretical risks with an
epidural blood patch (EBP), use is appropriate and safe
when initiated to treat postdural puncture headache
(PDPH). Acute and long-term follow-up of these
patients demonstrate that there is no evidence for any
unique risk from EBP in HIV-positive patients46.
Patients with HIV related oral lesions can prove
challenging. A careful inspection of the airway can
reveal a variety of HIV induced lesions such as oral
candidiasis with or without oropharyngeal involvement
(OPC), oral hairy leukoplakia (OHL), recurrent
aphthous-like ulcerations (RAU), oral Kaposi’s
sarcoma (OKS), orolabial herpes simplex infection
(HSV), oral herpes zoster infection (VZV), intraoral or
175
perioral warts (HPV), and HIV-associated periodontal
diseases. The lesions may cause pain, an abcess, or
edema that may make for a difficult airway.
In our experience, nebulized lidocaine for 15
minutes or simply cetacaine spray can facilitate the
process of an awake fiberoptic airway. Pain associated
with opening the mouth decreases should a jaw thrust
maneuver become necessary. An abscess or edema
near the pharynx may obstruct the view of the vocal
cords.In some cases involving painful oral lesions,
patients may refuse to eat, thus possibly leading to
malnutrition and hypoalbuminemia. In this scenario,
the clinical anesthesiologist should evaluate for any
signs of dehydration or electrolyte abnormalities that
may need correction before surgery. Furthermore,
drugs that bind to plasma proteins may be elevated,
and thus may require a reduction in dosage.
Postoperatively, criteria for management of
patients with communicable diseases are followed in
the postanesthesia care unit. Furthermore, nurses in
charge of care of these patients should not concurrently
take care of other patients in the hospital47.
Summary
Although modern medical care and current
therapies save and prolong the lives of many patients
with HIV/AIDS, the disease process has no cure and
will continue to present itself during the perioperative
period. All ages, young and old, may present with the
pathology and, therefore, the anesthesiologist must
have sound knowledge of the disease, treatment,
complications, and multiorgan manifestations. It will
be necessary to review the current treatment modalities
for HIV as pharmacologic strategies are ever evolving
with this disease process.
M.E.J. ANESTH 20 (2), 2009
176
Amir Baluch et. al
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M.E.J. ANESTH 20 (2), 2009
A PROPOSED CLASSIFICATION
OF SIMULATORS
Leonard M. Pott*, Arne O. Budde**
and W. B osseau M urray ***
Summary
This paper provides a coherent and comprehensive classification of simulators, using a
five letter coding system, and is based on the characteristics of the user interface and the logic
controller.
Introduction
Simulators are a well-accepted component of training and assessment1,2… A variety of
different classifications of simulators have been proposed2,5 but no accepted classification scheme
has yet been devised6.
The classification schemes in the literature tend to be broad, and with few categories. A
number of recent reviews have examined the various simulators currently available3,5. An ideal
classification should provide adequate information about the technology used in the design of
the simulator, an indication of how the simulator may be utilized, and the classification system
should be easy to remember. Understanding the structure of simulators may aid the choice of an
appropriate device for teaching and for assessing a particular skill. Additionally, an understanding
of the various design choices available may aid the design and construction of simulators.
Gaba has defined simulators as a “device that presents a simulated patient (or part of a patient)
and interacts appropriately with the actions taken by the simulation participant”7. Simulators are
devices which represent reality and allow for user interaction. Representations of reality are called
models, and the objective of any model builder is to extract those, and only those, aspects of reality
required by the model user, and incorporate the identified features into the model. Healthcare
simulators therefore do not include every feature of the patient or the patient’s environment.
In this paper we propose a coherent and comprehensive classification of simulators, based on
a five letter coding system.
From Department of Anesthesiology, Penn State Milton S Hershey Medical Center, Hershey, PA 17033, USA.
*
MB, BCh, Associate Prof.
** MD, Assistant Prof.
*** MB, ChB, Professor.
Corresponding author: Dr. Leonard Pott, Dept. of Anesth., Penn State College of Medicine, 500 University Drive, H 187,
Hershey, PA 17033, USA. Tel: (717) 531 1590, Fax: (717) 531 4110. E-mail: [email protected]
179
M.E.J. ANESTH 20 (2), 2009
180
Leonard M Pott et. al
Proposed classification
Simulators can be classified based on three
criteria.
Firstly, simulators can be classified in terms of
the input and output user interface. Simplistically,
input is what you perform, and output is the response
to your actions.
Secondly, our classification is based on the
method by which a specific output response is linked
to a particular input. We call the method which links
the input and output the interaction controller. The
interaction controller may be seen as a ‘black-box’.
The input is how the user interacts with the black-box,
and the output is how the black-box responds. How
the ‘black-box’ works is nevertheless important for
the instructor, and is therefore part of our proposed
classification.
The third component of the classification is
whether the simulator can be used for more than
one learner simultaneously, that is, the degree of
interactivity.
Each of these criteria will be discussed in more
detail below, and these three criteria will be subdivided
further. Each subdivision will be identified by a letter,
which will be introduced in the text.
1. The user interface. The user interface consists
of the input and output of the simulator, and is assessed
from the perspective of the user. Input and output can
be:
R Real-life
A Real-life input is a user input using equipment
and physical movements which are essentially the
same as those used in clinical practice. Real-life output
is when the user’s senses (visual, auditory, tactile, etc)
are stimulated in essentially the same way as in clinical
practice. A Real-life interface frequently involves the
movement of physical objects, for example squeezing
a bag to ventilate a simulated patient as the input, and
seeing the chest rise from a mannequin as the output.
How the simulator processes the input is part of the
interaction controller (which will be discussed in more
detail below), and not part of the user interface. Reallife input also includes any monitor or video display
found in normal practice. For example, entering
infusion rates on an infusion pump is a Real-life input
and a rise in blood pressure on the anesthesia monitor
is an example of the corresponding Real-life output.
Real-life input or output will be represented by
the letter ‘R’.
S Simulated
Simulated input and output involves an interaction
with the simulator which is different from a Real-life
interaction discussed above. Simulated input typically
involves the use of a mouse, or keyboard, or touchscreen, and Simulated output typically involves some
form of video display and may be accompanied by
sound. Using the above example again, Simulated input
would be to choose “intubate patient” from a menu in
a computer program as the Simulated input and then
seeing a video-clip of an intubated patient and hearing
breath sounds as the Simulated output. Infusion rates
would be entered by choosing a number for milliliters
per minute from a drop down menu per mouse click
and computer-based output would be a cartoon of
a dripping intra-venous line. Simulated input also
includes situations where the user tells another person,
such as the simulator operator, what the user intends to
do, and the second person transmits that information to
the interaction controller (see Table for examples).
Simulated input or output will be represented by
the letter ‘S’.
D Dual
Some simulators, particularly virtual reality
surgical simulators, have both Simulated (a video
screen) and Real-life output (haptic feedback on the
surgical instrument). When neither form of output is
dominant, then the output can be classified as Dual.
Whether a form of output is dominant can be decided
by excluding one form of output and checking whether
the simulator still functions adequately. For example,
the Anesthesia Simulator (Anesoft) has an auditory
output which can be switched off without affecting the
simulator significantly, and therefore does not have
Dual output. We are not aware of any current Dual
input simulators.
Dual input or output will be represented by the
letter ‘D’.
2. The interaction controller. The controller
will determine the appropriate output for any particular
input. Although the interaction controller may be
A PROPOSED CLASSIFICATION OF SIMULATORS
viewed as a ‘black-box’ by the user, it is the controller
which enables the interaction The linking of a particular
input to a specific output can be structured in a variety
of different ways.
One possibility is that the output is merely a
mechanical consequence of the input. An example
of a simulator with a mechanical controller is a
head and airway used for teaching, practicing and
assessing intubation skills. Other examples would
include hydraulic simulators. Mechanical controllers
are represented by the letter ‘N’ (for None) because
no specific interaction controller exists. We chose to
avoid the logical choice ‘M’ because that letter will be
used in another context, discussed below.
A second possibility is that a human operator may
activate the response depending on the input observed
by the operator. The user may not even be aware that
the operator is controlling the simulator, for example,
when the operator initiates a response by remote
control. The SimMan® is an example of an Operator
controlled simulation. What is significant is that the
operator makes some (subjective) decision about
what the output will be. Operator driven interaction
controllers are represented by the letter ‘O’.
The third possibility is that some form of logic
device, such as the CPU (Central Processing Unit) of
a computer, determines the output. For our proposed
classification we consider two alternatives, either
mathematically modeled or algorithmically driven
(rule-based).
Mathematically modeled.
In the case of mathematical modeling, the output
is calculated using a set of mathematical equations5.
These equations are expressed in terms of variables.
The specific values of the variables are determined by
the user input, and then the output is calculated by the
interaction controller. Mathematical models require
equations which attempt to describe physiological
events. Because the human body is extremely
complex, sophisticated modeling techniques are used5.
If the model only represents one aspect of the body’s
physiology then the modeling is simpler, for example,
the GasMan© program which models anesthetic gas
uptake and elimination8.
Mathematically modeled interaction controllers
are represented by the letter ‘M’.
181
An advantage of mathematical modeling is that
graphical representations of the physiological process
may easily be produced, which are useful for teaching.
Models such as GasMan© closely predict empirically
determined data9.
A relative disadvantage of mathematical modeling
of physiological processes is the complexity of the
software and the enormously high development costs.
Many of the mathematically modeled physiological
programs use very similar sets of equations5. However
the mathematical modeling of pharmacokinetic
simulators is relatively easy.
Algorithmically driven.
Algorithmically derived output is not calculated
but is pre-determined by the simulator developer. How
the simulator appears to the user at any particular time
is known as the state of the simulator, and these states
can change. The simulator program consists of a series
of branching conditional statements. Basically what
happens is that there is a transition from one state to
another state depending on the presence or absence
of various conditions. If the prespecified conditions
are met, then the state changes. The user provides the
input, and if the input is the condition necessary for a
state change, then there is a transition to the new state.
The resultant pathway essentially follows a clinical
decision tree10 where the choice at decision nodes
require input from the user.
A simple example of an algorithmic simulator is a
set of text documents (pages). The first page describes
a specific medical situation and poses a clinical
management question. Various alternative solutions are
offered as hyperlinks to the next text document. The
hyperlink selected reflects the user’s answer choice and
will determine which text document is presented next.
After making a series of choices the user will reach the
final document (page), and the user’s decision tree can
be reconstructed. Schwid calls the “pages” states, and
the “hyperlinks” transitions11. Because there are only
a limited number of states, he calls such a program a
finite state model11.
Tightly scripted simulation scenario’s using
Standardized Patients or involving mannequins
controlled by an operator, are also considered
M.E.J. ANESTH 20 (2), 2009
182
1. N - Mechanical
2. O - Operator (manual control by technician)
3. Central processing unit
a) M - Mathematically modeled
b) A - Algorithm driven
4. Combination
algorithmically driven.
Algorithmically driven interaction controllers are
represented by the letter ‘A’.
Combination.
The basic physiological function of a simulator
such as the METI® is primarily under the control
of a mathematical model. However, the simulation
technician can initiate an event or complication at
any time. This is an example of a primary controller
being overridden by a secondary controller. Primary
and secondary controllers refer to the software
design, and for convenience we refer to the primary
controller as Controller1 and the secondary controller
as Controller2.
In the Anesthesia Consultant Simulator©
transitions are primarily determined by user input
but may be overridden by the mathematical model.
For example, if the user of the simulation delays
the ventilation of a paralyzed patient for too long,
then the mathematical model will determine that the
patient’s oxygen saturation will fall and ultimately
the patient will die. Therefore the Anesthesia
Consultant Simulator© may be classified as primarily
an algorithm driven controller (Controller1) with a
secondary mathematical model capable of overriding
the algorithm (Controller2).
Logically, there can be no secondary controller
without a primary controller, so only one letter can be
used if no secondary controller is used; that is, instead
of writing an N in the second position this letter can be
omitted. For example, instead of writing AN for a pure
algorithmically driven simulator only A is written.
Alternative types of interaction controllers are:
a) Primary controller (abbreviated to
Controller 1)
O - Operator
M - Mathematical model
A - Algorithm
b)Secondary controller (abbreviated to
Controller 2)
O - Operator
M - Mathematical model
A - Algorithm
3. The environment determines if a simulator
can be used interactively by a group of two or more
persons.
G - Group interaction possible
I - Individual person only
B - Both options are possible
Using the above described definitions, simulators
can be characterized by a five letter coding system. We
propose the sequence:
Input: Output-Controller 1:
Controller 2-Interaction
Our simulator classification system is delineated
in Table 1 below:
Input. The first letter defines the user input interface and
indicates what kind of input is used; for example, R represents a
real-life input, or an S for a form of simulated input.
Output. The second letter tells which kind of output can be
expected, again either an R or a C.
Primary Controller. The third letter describes the primary
Table 1
Interface
Control
Interaction
Input
Output
Controller1
Controller2
R - Real-life
R - Real-life
N - None
N - None
G - Group
S - Simulated
S - Simulated
O - Operator
O - Operator
I - Individual
D - Dual
D - Dual
M - Mathematical
A - Algorithm
M - Mathematical
A - Algorithm
B - Both
183
controller, which could be N, O, M or A (see text).
Secondary Controller. The fourth letter describes the
secondary controller which, if present, may override the primary
controller.
pacemakers was first introduced in 1974 and then
further developed and revised13-15. Our proposal is that
simulators be classified using a similar method.
Interaction. The fifth letter indicates that the simulator
can be used by a Group or by a Individual person only,
or Both alternatives (G or I or B).
A simulator is the device used, and simulation is
the process. Some of the more complex simulators, such
as the METI can be used in more than one simulator
mode. So, for example, the METI mannequin can be
switched off and still be used to practice intubation.
Therefore, in terms of function, one particular simulator
can be classified in different ways. It is our suggestion
that simulators are primarily classified in terms of their
structure. If however, a simulator is used differently
(such as the METI for intubation practice), then a
statement such as “….the METI, used as a RRNS
simulator…” is applicable. Examples can be seen in
Table 2.
Discussion
Classification and coding systems have been
used in many fields to aid the understanding and use of
products. An example is the classification of electrical
cables by the National Electrical Code. The use of
coding systems is well established in gynecology
and obstetrics using the GPTPAL code12 as well
as in cardiology, where a specific code for cardiac
Table 2
Some examples using the proposed classification
Input
Output
Controller 1
Controller 2
Interaction Task Example
Checking
peripheral pulses
Simulator
Example
Comment
METI,
SimMan, SP
METI expensive, SP possibly
better choice
SP
inappropriate to train this
task
METI,
SimMan
hands on training, no harm
for the simulator
Anesoft
how to diagnose, cognitive
skills
SP
Learn where to put hands
R
R
N
I
R
R
N
I
R
R
O
N
I
S
S
M
A
I
R
R
O
N
I
R
R
N
N
I
R
R
A
O
I
S
R
A
O
I
R
R
N
I
R
R
O
I
S
S
A
M
I
S
S
M
A
B
R
R
M
O
B
R
S
M
R
D
N
M
I
R
R
Various
Various
G
CRM
S
S
M
A
G
Emergency room Second Life
triage
I
Needle
decompression
for a tension
pneumothorax
Palpation of
tender abdomen
Intubation
METI,
SimMan,
Learn were to put hands
Resusci Anne
SP, METI,
Simulation of pain based on
SimMan
Algorithm
Student (S)imulates
SP
palpation: «Imagine I would
touch you»
Laerdal Head
sufficient to train the task
METI
more realistic environment
due to full body mannequin
Anesoft
Teaching of theory, when and
how to intubate
Teaching of theoretical
Advanced Cardiac Anesoft, Body principles
Life Support
(ACLS)
METI
Hands on training
Laparoscopic
suturing
LapSim VR
simulator
Vitual reality
ProMIS AR
simulator
Augmented reality, more
realistic due to haptic
feedback
Meti, SimMan,
Resuci Anne
Still experimental
M.E.J. ANESTH 20 (2), 2009
184
The proposed classification code serves to
summarize some of the features of a particular
simulator, but cannot include all information about
a simulator. Additional information that may be
necessary will depend on the circumstances and may
include, for example, the product name and supplier,
or the physical dimensions. Some classifications
make a distinction between high-fidelity and lowfidelity simulators16. Our classification makes no such
distinction because the degree of realism depends to a
large extent on the surroundings in which the simulator
is used3,4,17.
Rall and Gaba have stated that “(s)ome
individuals consider the screen-only microsimulator
(also known as a screen-based simulator) to be a
training device and not a simulator”6. We have made
no distinction between simulators used for training and
those used for assessment, and agree with the inclusive
approach of Cumin and Merry3. Any device which is
a representation of reality and allows for interaction is
considered a simulator.
We have chosen letters for the code which are
unique in each category, so that if a category of the
classification is not relevant in a particular situation,
it may simply be omitted. For example, -MA(mathematical model overridden by an algorithm) only
refers to the interaction controller, and -RR- (real-life
input, real-life output) only refers to the user interface.
We chose the term ‘Real-life’ rather than the alternative
‘Physical’ because the term is intended to convey the
sense that the object looks and feels like the equivalent
real-life object.
A classification of simulators such as the one
presented in this paper has some major advantages.
1. By specifying the classification of the
controller the software architecture is clear; something
which is not always immediately apparent using other
classifications. Knowing that the primary controller is
algorithmic indicates that the program can be relatively
easily modified.
2. If a simulator does not have an ‘R’ (Real-
life) for input then it is extremely unlikely that such
a simulator could be used for training, or evaluating,
psychomotor skills[3]. In order to become proficient
at a motor task practice is necessary, and only a reallife input simulator will provide the conditions for
practice necessary to develop the coordination of
motor skills. While other classes of simulator may
be usefully employed to provide the theoretical and
cognitive background, there is probably no substitute
for physical practice.
3. If objective assessment is desired then any
simulator with an ‘O’ in either of the controller
positions, that is, any simulator which is controlled or
overridden by the instructor, is unlikely to be suitable.
As soon as a person, who is aware of the situation
pertaining to the evaluation, has the discretion to alter
the simulation sequence then the evaluation becomes
subjective. On the other hand, if the operator works
according to a very rigorous and precisely defined
script then the operator is essentially an algorithmically
driven controller, and with little effort can be replaced
by a software program. To the extent that the script
remains undefined, the assessment is subjective.
4. Certain theoretically possible classes of
simulator have not yet been constructed, and this
classification identifies simulators of the form S-R,
that is computerized input and a real-life output.
Depending on the educational or assessment objectives,
it may prove useful to design and build a simulator
representing a specific category.
5. SS-A simulators are eminently suitable for
Web-based applications, whereas the modification
of simulators for Web applications with R in either
position will be problematic.
We present this classification of simulators in the
hope that, by adopting a simple coding of simulators,
communication in the simulation community will
be enhanced. Although our proposal may require
modification and adaptation, we believe that the
classification is coherent, comprehensive and easy to
use.
185
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9:394-399.
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M.E.J. ANESTH 20 (2), 2009
MODERN STRATEGIES FOR THE ANESTHETIC
MANAGEMENT OF THE PATIENT
WITH DIABETES
Abhinav Gautam*, Amir Baluch**, Alan Kaye***
and E lizabeth A. M. F rost ****
Summary
Diabetes Mellitus (DM) is an endocrine disease with high incidence. Long-term complications
involve the eyes, kidneys, nerves, and blood vessels, resulting in hypertension, cardiac ischemia,
atherosclerosis, and renal failure, among other syndromes. Given this prevalence, anesthesiologists,
especially those who work with older patients, may expect to encounter some aspect of diabetes
almost every day. Appropriate preoperative evaluation and rational intraoperative and postoperative
management of this complex disease in elective and emergency circumstances are essential.
Recent studies have emphasized the need to maintain tight perioperative glycemic control and new
guidelines have been presented.
Epidemiology/Incidence
In the United States, approximately 20.8 million people (7% of the total population) suffer
from diabetes mellitus. Currently, type 2 diabetes represents 90-95% of all cases, leaving type 1
diabetes to account for the remaining 5-10%1. Approximately one third of diabetic patients are
presently unaware of their pathology and therefore do not seek care. Up to half of all newly identified
cases of renal failure are related to diabetes mellitus. Those with diabetes have a significant chance
of also suffering from other co-morbidities, including stroke and coronary artery disease (CAD).
Diabetes is the 7th leading cause of death1. As well, compared to the non diabetic population,
diabetic patients have an increased rate of hospitalization frequency, longer hospital stays, and a
greater number of ambulatory care visits2.
*
Medical Student, Louisiana State University Health Science Center, New Orleans, LA,USA.
** MD, Anesthesia Resident, Jackson Memorial Hospital/University of Miami, Miami, FL,USA.
*** MD, PhD, DABPM, Professor and Chairman, Department of Anesthesiology, LSU Health Science Center, New Orleans,
LA,USA.
****MD, Professor, Department of Anesthesiology, Mount Sinai Medical Center, New York, NY, USA.
Corresponding author : Elizabeth Frost MD, Professor, Dept. of Anesthesiology, Mount Sinai Medical Center, New York,
N.Y., USA. E-mail: [email protected]
investigative products in this lesson.
187
M.E.J. ANESTH 20 (2), 2009
188
Abhinav Gautam et. al
Glucose Physiology
Pathology
Glucose is a crucial fuel source, and insulin
facilitates glucose movement into cells in a process
that also requires potassium and phosphate. Red
blood cells, healing wounds, the brain, and the
adrenal medulla require glucose for fuel, totaling
approximately 2 mg/kg/min. When controlling blood
glucose, close monitoring is crucial. Reagent strips
containing glucose oxidase, used in conjunction
with glucometers, provide rapid and reliable results.
It is imperative to know the insulin regimen or oral
hypoglycemic agent of each patient and then measure
the blood glucose preoperatively, intraoperatively, and
postoperatively. The degree of end-organ damage,
coronary artery disease, and autonomic neuropathy
can contribute to the risk of aspiration, myocardial
infarction, and peripheral neuropathy.
Hyperglycemia of diabetes is the consequence of
relative or absolute deficiency of insulin and a relative
or absolute excess of glucagon. In type 1 diabetes, there
is an absolute deficiency in insulin production, and
without insulin, patients die. These patients eventually
become dependent on exogenous insulin to prevent
lipolysis and eventually ketoacidosis. The onset of type
1 diabetes usually occurs by adolescence, although
it may occur at any age and is thought to result from
autoimmune destruction of islet cells in the pancreas.
Hyperglycemia
Hyperglycemia (>120 to 200 mg/dL) is most often
caused by insulin deficiency, insulin receptor resistance,
or glucose overadministration. Hyperglycemia
produces osmotic diuresis; exacerbation of brain,
spinal cord, and renal damage by ischemia; delayed
gastric emptying; hypophosphatemia; delayed wound
healing; and impaired white blood cell function.
Maternal hyperglycemia increases the risk of neonatal
jaundice, the risk of neonatal brain damage, and fetal
acidosis if the fetus becomes hypoxic.
Even with supramaximal levels of insulin, adults
can only use glucose at a rate of 3 to 5 mg/kg/min at
rest (approximately 240 mL/hour of 5% solutions). The
maximal rate of metabolism is less in stress states and
more with increased metabolic rates. In general, the
rate of administration should be limited to 2 to 3 mg/kg/
min (120 to 180 mg/kg/hour), which is 100 g/hour for a
70-kg person (200 mL of a 5% dextrose solution/hour).
Healthy infants and children become hyperglycemic if
5% dextrose is included in maintenance fluids. The
maximal rate of glucose disposition in young children
is 4 to 8 mg/kg/min, and the optimal rate is less than 5
mg/kg/min. In reviewing the literature, it is not clear if
glucose administration is necessary for intraoperative
management of most patients.
Type 2 diabetes is characterized by a relative
deficiency in insulin, typically caused by insulin
resistance. The onset of this type of diabetes is usually
in adulthood, although there is a trend of decreasing
age of onset of type 2 diabetes. Type 2 diabetes almost
certainly has a heterogeneous group of etiologic
factors. However, commonly associated findings in
type 2 diabetes are obesity, abnormal insulin levels,
and a strong genetic component.
A third type of diabetes mellitus is gestational
diabetes. Gestational diabetes is defined as any degree
of glucose intolerance with the onset first recognized
during pregnancy. Gestational diabetes complicates
approximately 4% of all pregnancies in the United
States, which results in about 135,000 cases annually.
Clinical recognition of gestational diabetes is important
because therapy and antepartum fetal monitoring can
reduce perinatal morbidity and mortality. Maternal
complications related to gestational diabetes include
an increased rate of cesarean delivery.
During the past decade, a new disorder known as
syndrome X has been described. As the name implies,
it is a syndrome rather than a specific disease state.
The hallmark of syndrome X is insulin resistance with
hyperinsulinemia. The underlying pathology is similar
to type 2 diabetes; however, syndrome X patients do not
exhibit hyperglycemia. Syndrome X patients may never
develop type 2 diabetes. The clinical significance of
this condition stems from its association with multiple
metabolic abnormalities, including low levels of highdensity lipoprotein (HDL), increased blood pressure, and
increased plasminogen activator inhibitor-1 levels. All
these abnormalities have definite or possible association
with coronary artery disease. Whether syndrome X and
type 2 diabetes are on a spectrum of disease with insulin
MODERN STRATEGIES FOR THE ANESTHETIC MANAGEMENT OF THE PATIENT WITH DIABETES
resistance as a common denominator or are totally
separate entities has yet to be clarified.
Anesthetic Considerations
Pre-Operative
The preoperative physical examination and history
may reveal extensive diabetic neuropathy, which may
be seen as orthostatic hypotension, syncopal episodes,
mononeuropathies or polyneuropathies, and erectile or
bladder dysfunction. Patients may present with a number
of additional findings, including cerebrovascular
disease, renal dysfunction, microalbuminemia, and
tight, waxy skin. In an estimated 30% to 40% of
diabetic patients, glycosylation of the atlanto-occipital
joint may limit joint mobility and cause difficulty
with airway management (i.e., stiff-neck syndrome)4.
Laboratory evaluation of hemoglobin A1c is an accurate
measure of the severity of hyperglycemia and has
been shown to correlate directly with increased rates
of complications. Conversely, lower hemoglobin A1c
values are associated with decreased risk and can be
considered a measure of the quality of the diabetic care
or lack of presence of the disease itself. Hemoglobin
A1c provides the best evidence of overall blood glucose
control over the past 1 to 2 months and is replacing
the oral glucose tolerance test as the gold standard
for diagnosing diabetes and for level of control of the
disease5. A Hemoglobin A1c of ≤ 7% is considered to
be indicative of appropriate glycemic control and can
be followed on oral hypoglycemic agents or insulin
preparations. Basic electrolyte and renal function
tests should be evaluated, especially if the patient has
frequent urinary tract infections or renal impairment6.
The regimen selected to manage diabetics
undergoing surgery has become standardized in most
facilities in recent years, with a target glucose and
maintenance in the range of 80-110 mg/dl. Frequent
glucose monitoring and preparation for insulin
administration are essential for the diabetic patient and
this includes a preoperative level, routine intraoperative
levels, and postoperative assessment. Short-acting
insulin morning doses are usually held in as much as
the patient will be NPO and not eating breakfast the
morning of surgery. Intermediate and longer acting
insulin preparations are typically continued. Shorter
189
acting insulin is administered to target the 80-110
mg/dl range. Most protocols are based on an average
response for each unit of short acting insulin to lower
blood glucose levels by approximately 25 mg/dl.
Perioperative
Because diabetes affects multiple organ systems,
the perioperative impact can be profound. Several
clinically relevant issues should be considered during
perioperative anesthetic management:
1. Diabetes affects oxygen transport by causing
glucose to covalently bind to the hemoglobin
molecule, decreasing oxygen saturation and red
blood cell oxygen transport in diabetic patients8.
2. A common complication of diabetes is autonomic
dysfunction. Patients in whom diabetes has been
poorly controlled for many years often have
damage to the autonomic nervous system. One
study9 demonstrated that diabetic patients with
previously diagnosed autonomic dysfunction are
at increased risk for intraoperative hypothermia.
The pathogenesis may be related to inappropriate
regulation of peripheral vasoconstriction to
conserve body heat.
3. Autonomic dysfunction also affects the body’s
ability to regulate blood pressure, leading
to significant orthostatic hypotension. This
underlying defect is caused by a lack of appropriate
vasoconstriction. Denervation may also involve
vagal control of the heart rate. The changes in
heart rate seen with atropine and β-blockers are
blunted in patients with significant autonomic
dysfunction10.
4. Damage to the autonomic nervous system can
affect the choice of anesthetic technique. Patients
are at significantly increased risk of hypotension
caused by induction agents such as thiopental or
propofol. Therefore, because of its considerably
lower incidence of cardiovascular side effects,
etomidate or a reduced dose of propofol are the two
most common induction agents for this population
of patients.
5. Diabetes has well-defined adverse effects on the
cardiovascular system. Men who suffer from
diabetes have twice the age-adjusted risk for
M.E.J. ANESTH 20 (2), 2009
190
coronary artery disease. The risk for women is
tripled, indicating that they may be even more
sensitive to the cardiovascular effects of diabetes11.
Data show that patients with diabetes may be at
even greater risk for coronary artery disease than
was previously suspected. One study revealed that
patients with type 2 diabetes had as great a risk for
myocardial infarction as nondiabetic patients who
already had a previous myocardial infarction12. This
information reinforces the point that diabetic patients
must be carefully evaluated preoperatively for
coronary artery disease. It must also be remembered
that diabetic patients are more likely to have silent
ischemia. They may not experience the classic chest
pain and tightness associated with ischemic heart
disease. Questions regarding exercise tolerance
and shortness of breath with exertion may provide
important information regarding underlying heart
disease or the degree of compensation.
6. Diabetes affects the gastrointestinal tract in several
ways. First, it damages the ganglion cells of the
gastrointestinal tract, inhibiting motility, delaying
gastric emptying and overall transit time through the
gut. Theoretically, all diabetic patients have delayed
gastric emptying and many practices treat these
patients with the same considerations as patients
with full stomachs. Thus, preoperative treatment
with agents that inhibit acid secretion, neutralize
stomach acid, and increase gastric emptying
(e.g. famotidine, bicitra, and metoclopramide) is
essential. Rapid-sequence induction is commonly
employed to try to minimize the risk of aspiration.
Peri- and intraoperative
Perioperative and intraoperative glycemic-control
regimens depend on several factors. Patients with type
1 diabetes are at risk for ketonemia if they are without
insulin. The risk of ketosis is amplified when the patient
undergoes the stress of surgery. Second, the degree to
which blood sugar levels are chronically controlled
affects management. The amount of exogenous insulin
a patient normally requires is important in deciding
how blood glucose should be treated intraoperatively.
The magnitude of the surgery plays an important role in
determining therapy. There are few prospective studies
comparing regimens, even though there are many
different protocols for preoperative and intraoperative
insulin management. Some of the more common
protocols are discussed.
Sliding Scale:
The typical “sliding scale” is destined to fail
because it involves the administration of a fixed dose
after documentation of hyperglycemia. A revised
protocol has been used in our department at LSU
School of Medicine in New Orleans succesfully to
manage hyperglycemia and provides excellent glucose
control througout the perioperative period [Fig. 1:
Insulin protocol].
Figure/Chart 1
Insulin Infusion Protocol Intravenous Insulin Infusion for
Adults
1. Discontinue all previous diabetes medications including
SQ insulins.
2. Mix Infusion: Human Regular Insulin 100 units in 100 ml
NS (1 Unit/ml)
3. Check Potassium: if less than 3.5 mEq/L, call MD before
starting infusion.
4. Initiate Insulin infusion:
Algorithm 1: Start with most patients
Algorithm 2: Patients with post coronary bypass surgery, or
solid organ transplantation, or receiving glucocorticoid therapy,
or diabetes receiving more than 80 units of insulin/day.
Patient Age__________
Weight_______kg
Blood glucose Initial Insulin Infusion rate Units/hour
level (mg/dl)
Algorithm 1
Less than 60
61-109
110-119
120-149
150-179
180-209
210-239
240-269
270-299
300-329
330-359
360-399
400 or Greater
5. Monitoring:
Algorithm 2
Other
Call Anesthesiologist
Hold insulin infusion, check glucose in 1 hour
and follow the schedule
0.5
1
1.5
2
2
3
3
4
4
6
8
1___________
1.5__________
2___________
3___________
4___________
5___________
6___________
7___________
8___________
10__________
12__________
a. Check Glucose every 1 hour until 3 consecutive levels to reach the
Goal of 80-110 mg/dl range; Follow the titration schedule if the goal
is not achieved
b. When the levels are in desired range 80-110 mg/dl; decrease the
check of Blood Glucose every 2 hours x 4 hours then every 4
hours.
c. Restart the process at 5a every 1 hour if there is a change in the
infusion rate.
(Modified from the Ochsner Medical Center in Kenner, Louisiana)
Table 1
Krinsley Protocol
Diet
Monitoring
NPO
Q6 hours. 6AM, Noon, 6PM, Midnight
PO Diet
1 Hour Before Meals. QHS
Tube Feedings Q6 hours. 6AM, Noon, 6PM,
Midnight
Glucose Value Action (SubQ insulin)
<140
No Treatment
140-169
3 units Regular Insulin
170-199
4 units Regular insulin; Recheck glucose
value in 3 hours
200-249
value in 3 hours
250-299
8 units Regular insulin; RechecK glucose
value in 3 hours
300 +
value in 3 hours
On the day of surgery, severe diabetic patients
receive a dextrose infusion (2 mg/kg/min) and it is
started at the time a meal would have been ingested,
and glucose is measured preoperatively. For patients
currently receiving insulin, an insulin infusion (0.25
units/mL) is started at a rate of 0.5 to 1.25 units/
hour, depending on the amount of insulin normally
administered and the current glucose level. Blood
glucose is monitored hourly, and the infusion rate
is adjusted to maintain glucose at 80 to 110 mg/dl.
Once the blood glucose level is stable, urine glucose
levels and ketone bodies can be checked to ensure that
glycosuria due to a low threshold does not confuse
interpretation of urine.
For patients requiring more than 50 units/
day, which is an indication that the diabetes is
poorly controled, or for the insulin-treated diabetic
undergoing major surgery, a more intense monitoring
and treatment regimen has been described. Long- and
intermediate-acting insulin is discontinued, and the
patient is managed with an intravenous insulin infusion
or scheduled subcutaneous insulin perioperatively.
Twelve hours before anesthesia oral intake must be
stopped because significant gastroparesis exists in
these patients. Patients are administered a histamine
(H2) blocker along with the gastric-emptying drug
metoclopramide the night before and the morning of
surgery. This management is quite challenging and
time consuming for the healthcare team.
191
When oral intake stops, maintenance fluids
containing dextrose at 2 mg/kg/min are started and
should be continued throughout the procedure. Glucose
is measured before induction and hourly until stable
postoperatively. Urinary ketones are measured every 6
hours. An insulin infusion is started with an initial rate
of 1 to 2 units/hour or to match the amount administered
hourly the previous day if good control was achieved.
Higher doses are required for patients with obesity,
liver disease, steroid therapy, or severe infection.
Extremely high rates (≥ 80 units/hour) may be required
during stressful procedures (e.g., cardiopulmonary
bypass)13. The frequency of glucose measurement can
be decreased once the glucose level has remained stable
and within the desired range for 3 hours.
Provided a patient has reasonable glucose control
(≤ 130 mg/dL), an alternative to an infusion would be
to hold all short-acting insulin and give one half of the
intermediate- or long-acting insulin the morning of the
surgery. It is imperative to provide close perioperative
glucose and electrolyte monitoring. Though poorly
controlled glucose postoperatively is a cause of adverse
outcomes, there is no clear consensus about the specific
method of insulin therapy or the exact range of blood
glucose which can affect morbidity or mortality14.
Cerebrovascular accidents, peripheral vascular
disease, and cardiovascular infarction are commonly
encountered in diabetic patients. The diabetic patient
typically has accelerated atherosclerosis related to their
disease process and therefore, through preoperative
assessment is essential.
Strategies designed to reduce the risk of labile
blood pressures and myocardial ischemia related to
autonomic or vascular disease may include: β-blockade
to blunt the stress of induction, a narcotic-based
anesthetic to minimize cardiopulmonary depression,
and prophylactic nitroglycerin in these patients with
their significant risk of coronary artery disease.
Commonly associated conditions include obesity
and stiff cervical joints, which may make airway
management challenging. Associated cardiovascular
conditions often result in the need for additional
invasive monitoring.
Multiple protocols have been published utilizing
chemistry-based analyzers among cardiovascular
surgery patients, with targeted blood glucose ranges of
M.E.J. ANESTH 20 (2), 2009
192
72-144 mg/dl, 100-139 mg/l, or 100-200 mg/dl without
clinically significant hypoglycemia15 (Table 1).
Postoperative
There are a few oral medications that should be
reinstated with caution. Generally the preoperative
diabetes treatment regimen (oral or oral plus insulin)
may be reinstated once the patient is eating well.
However, there are a few caveats for certain oral
hypoglycemic agents. Metformin should not be
restarted in patients with renal insufficiency, significant
hepatic impairment, or congestive heart failure.
Sulfonylureas stimulate insulin secretion and may
cause hypoglycemia; they should be started only after
eating has been well established and serum glucose
levels have been checked and are in the appropriate
range. A step-up approach can be used for patients
on high dose sulfonylureas, starting at low doses and
adjusting them until the usual dose is reached.
As discussed earlier, insulin infusions should
be continued in patients who do not resume eating
postoperatively. Maintaining a tight glucose control
(<110 mg/dL) improves patient outcomes in patients in
the ICU or OR16. However it must be noted that there
can be a significant financial burden on the hospital to
effectively carry out tight glucose control on multiple
patients simultaneously. Once it seems likely that
solid food will be tolerated, the insulin infusion can be
discontinued 15 to 30 minutes prior to eating, and the
patient given subcutaneous insulin at that time.
Patients who were taking subcutaneous insulin
in the early postoperative phase, before alimentation
is restarted, should continue this treatment along
with intravenous dextrose (5 to 10 gm of glucose/
hr = 100 to 200 mL/hr of D5W solution) to prevent
hypoglycemia.
Complications
Acute Hyperglycemia
The cellular effects of acute hyperglycemia are
poorly understood, but reports have begun to shed
some light on alterations in normal cell functions at
the molecular level. One study17 showed that acutely
elevated glucose levels depress endothelin-induced
calcium signaling in rat mesangial cells, thereby
depressing the contractile state of glomerular cells.
Such information supports the hypothesis that acute
hyperglycemia can affect cellular functions and may
lead to clinically evident pathology.
Acute consequences of elevated serum glucose
levels include impaired wound healing, dehydration,
impaired immune system response, and proteolysis.
Osmotic diuretic effect of high serum glucose levels are
due to the dehydration seen during acute hyperglycemia.
Patients with diabetes are well known for having poor
wound healing, which is commonly believed to be
caused by impaired blood flow to the wound. However,
there is evidence that acute hyperglycemia may impair
fibroblast activity and impair vitamin C uptake by
cells, thereby inhibiting new collagen synthesis18.
In addition to delayed wound healing, elevated
glucose levels also inhibit immune function, and
increase the risk of postoperative infection. One
study19 suggests that continuous insulin infusions, used
to control intraoperative and postoperative glucose
levels, decrease the incidence of sternal wound
infections after cardiac surgery. A second study20
found that aggressive glucose control intraoperatively
significantly increased neutrophil activity in vitro.
Alveolar macrophages from normal hosts demonstrate
impaired respiratory burst when exposed in vitro to
elevated glucose concentrations21. Taken together, these
data indicate that tight glucose control intraoperatively
may significantly influence the ability of patients to
recover more quickly from surgery.
Long term complications of diabetes can be
classified into macrovascular and microvascular
disease. Manifestations from these two separate
pathological pathways usually co-exist in the affected
patient. Macrovascular disease, which affects the
large vessels of the body, such as the coronary or
lower extremity arteries (e.g., femoral, popliteal),
may result in myocardial infarction and peripheral
vascular occlusive disease, respectively. Up to 80%
of deaths in people with type 2 diabetes are attributed
to cardiovascular disease and stroke22. The increased
prevalence of macrovascular disease in people with
diabetes is due to many factors including, but not
limited to, obesity, lipid abnormalities, hypertension,
hyperglycemia, hypercoagulation, platelet dysfunction,
inflammation, and endothelial dysfunction23,24.
Diabetic microvascular disease affects the small
vessels, such as those supplying the retina, nerves,
and kidneys. End organ damage can lead to diabetic
retinopathy and blindness, diabetic neuropathy,
which may result in lower limb amputation, and
diabetic nephropathy, often leading to end-stage renal
disease requiring dialysis or transplantation. It is well
established that chronic hyperglycemia results in
these primary chronic microvascular complications
of diabetes25. Diabetes is the leading cause of renal
failure and adult blindness in developed countries,
contributing to >43,000 new cases25 of end-stage renal
disease and 24,000 new cases of vision loss each year
in the US.
Neural Problems
There is both clinical and experimental evidence
which suggests that hyperglycemia lowers the neuronal
ischemic threshold. In the hypoxic setting, neural tissue
cannot metabolize sugar via an aerobic pathway and
consequently the sugars undergo anerobic metabolism.
The anaerobic pathway produces lactate which further
damages the neural tissue and expands the area of
necrosis. A recent study by McGirt demonstrated that
hyperglycemic patients not on tight glucose control
undergoing carotid endarterectomies had an increased
risk of perioperative stroke, myocardial infarction, and
death26.
Conversely there have been recent studies
suggesting that tight glucose control may not be the
magic bullet in improving patient outcomes. A study
by DeBrouwere suggested that clinical outcomes of
cardiovascular surgery patients were not improved by
tight glucose control27. Furthermore a study in 2005 by
Butterworth showed that tight glucose control did not
improve neurological outcomes in patients undergoing
open heart surgery28.
Renal problems
A thickening in the glomerulus is the earliest
detectable change in the course of diabetic nephropathy.
The glomerular thickening causes podocyte
broadening and loss in overall podocyte number29.
Microalbuminuria occurs when the kidney allows more
albumin to pass through the “filter”. It can appear 5 to
10 years before other symptoms and is a fairly accurate
193
indicator for diabetic disease30. Increasing numbers of
glomeruli are destroyed by nodular glomerulosclerosis
as diabetic nephropathy progresses. Now the amounts
of albumin being excreted in the urine increases, and
may be detected by ordinary urinalysis techniques.
Kidney biopsy clearly shows diabetic nephropathy at
this stage.
Kidney failure provoked by glomerulosclerosis
leads to fluid filtration deficits and other disorders of
kidney function, hypertension and fluid retention result31.
Other complications may be arteriosclerosis of the renal
artery and proteinuria (nephrotic syndrome)32. Also other
symptoms may include: edema (usually around eyes),
anorexia, nausea, vomiting, malaise, fatigue, headache,
frequent hiccups, generalized itching.
Diabetic Ketoacidosis
Diabetic ketoacidosis is an emergent condition
often manifested in the diabetic patient with leukocytosis
and an acute surgical abdominal emergency or with
nausea, vomiting, lethargy, and signs of hypovolemia.
The priorities are to restore intravascular volume
(usually rapid intravenous administration of 1 L of
saline); administer regular insulin (0.2 unit/kg) followed
by an infusion at a rate of 0.1 unit/kg/hour; eliminate
the ketonemia; control blood glucose; and correct the
underlying problem (e.g., antibiotics for urosepsis or
pneumonia). Patients with ketoacidosis are dehydrated
as a result of glucosuria; because the dehydration is
caused by water and electrolyte loss, colloids are not
indicated. If the patient’s osmolality is elevated, 0.45%
sodium chloride can be administered, and the volume
administered should be guided by the hemodynamic
response, acid-base status, and urinary output. Urine
or blood ketones may be monitored every 2 hours after
the blood glucose is within 100 to 200 mg/dL. The
rates of glucose and insulin infusions should both be
increased if ketones are still present.
Osmotic diuresis promotes loss of sodium,
potassium, magnesium, and phosphate. Despite totalbody deficiencies, however, their concentrations may
be elevated at the time of presentation because of
severe water loss. The best treatment for hyperkalemia
in these patients is appropriate therapy for the diabetic
ketoacidosis. Potassium levels decrease rapidly with
appropriate volume replacement and insulin therapy.
M.E.J. ANESTH 20 (2), 2009
194
After volume expansion has begun most patients
require electrolyte replacement. Alternatively, severe
hyperglycemia may extract water from the intracellular
space and may dilute the electrolyte concentrations.
Potassium should not be administered if its initial level
is elevated or patient is anuric. As hydration improves
and urinary output increases, potassium, magnesium,
and phosphorus should be administered and levels
monitored frequently. In general, acidosis should not
be treated with buffers. As insulin and glucose levels
improve, the ketoacidosis is corrected, and the lactic
acidosis resulting from poor perfusion responds to
intravascular fluid replacement. If the pH approaches
7.15, the bicarbonate ion concentration is less than 10
mEq/L and hypotension fails to respond to intravascular
fluid administration, sodium bicarbonate therapy may
be required.
Hypoglycemia
Hypoglycemia (≤ 50 mg/dL) is dangerous,
because glucose is the sole fuel source for much of the
brain and can result from too much insulin delivery.
Threshold levels depend on age. Irritability, seizures,
tachycardia, hypotension, and respiratory failure are all
signs of hypoglycemia. Symptoms commonly occur in
adults at blood glucose concentrations below 60 mg/dL
or in infants with levels below 30 mg/dL. Symptoms are
seen at higher levels in diabetics than in nondiabetics
and are generally obscured by general anesthesia since
irritability and other central nervous systoms related
manifestations can not be observed while unconscious
and tachcardia along with hypotension can be easily
misinterpreted intraoperatively as having a different
origin. Neurologic and electroencephalographic
depression appears at 50 to 55 mg/dL in nondiabetics
and 70 to 85 mg/dL in diabetics33. There are no studies,
as of yet, evaluating glucose levels and brain wave
monitor changes in humans.
During labor, maternal starvation-induced ketosis
has adverse fetal effects, including fetal ketonemia,
hypoxia, and fetal lactic acidosis35. Neonates are at
increased risk for hypoglycemia because of limited
glycogen stores and from large amounts of fetal insulin
production in response to gestational hyperglycemic
states. Adults are also at risk for hypoglycemia from
inadequate gluconeogenesis coupled with inadequate
nutritional intake or from excess insulin (e.g., from an
insulinoma, pancreatic islet cell adenoma, or carcinoma;
iatrogenic overadministration). Hypoglycemia can
also follow too abrupt cessation of dextrose infusion
during total parenteral nutrition (i.e., reactive
hyperinsulinemic states). Inadequate gluconeogenesis
occurs in liver failure, cortisol deficiency (primary or
secondary), inadequate glucagon response, growth
hormone deficiency, and during β-adrenergic blockade.
Fasting in women is likely to produce hypoglycemia
in 24 hours, whereas men tolerate about 72 hours of
fasting35. The incidence of hypoglycemia in healthy
infants and children is low (2 of 446) with 4 to 8 hours
of fasting36. Fetal hypoglycemia occurs if maternal
glucose is greater than 150 mg/dL, because glucose
crosses the placenta, inducing fetal insulin secretion.
Treatment consists of an intravenous bolus of 5 g of
dextrose followed by increasing the rate of dextrose
infusion by 1 to 2 mg/kg/min.
Neural Tissue Damage
Clinical and experimental evidence suggests
that hyperglycemia lowers the neuronal ischemic
threshold, potentiates stroke volume in focal ischemia,
and is associated with morbidity and mortality in
the surgical critical care setting. It remains unknown
whether hyperglycemia during carotid endarterectomy
(CEA) predisposes patients to perioperative stroke and
operative related morbidity and mortality. Independent
of previous cardiac disease, diabetes, or other comorbidities, hyperglycemia at the time of CEA was
associated with an increased risk of perioperative stroke
or transient ischemic attack, myocardial infarction,
and death. Strict glucose control should be attempted
before surgery to minimize the risk of morbidity and
mortality after CEA26.
Treatment options and new guidelines
Glycemic Control
Because of co-morbidities and the high risk
of coronary heart disease, which may be relatively
asymptomatic compared to the non diabetic
population, careful assessment of diabetic patients
prior to surgery is essential to maximize the best
possible outcome. Diabetes mellitus is also associated
with increased risk of perioperative infection35 and
postoperative cardiovascular morbidity and mortality38.
Hyperglycemia occurs commonly in critically ill
diabetic patients; but also, is frequent in those who
have a history of euglycemia/normoglycemia. This is
particularly seen in patients who have been placed on
steroids over a period of time.
Surgery and general anesthesia can result in a state
of relative insulin hyposecretion and insulin resistance39
by release of hormones such as glucocorticoids,
growth hormone, catecholamines, and glucagon40.
The magnitude of counterregulatory hormone release
varies per individual and is related to the extent of the
surgery and additional postoperative factors such as
sepsis. Another factor in perioperative management is
the wide variation in nutritional consumption41.
Many different data sets show that tight glycemic
control decreases mortality and morbidity. Tight
glycemic control in ICU patients has been shown to
result in reduced morbidity from the prevention of
acquired kidney problems, accelerated weaning times
off the ventilator, and faster discharge from the ICU/
hospital.
A prospective randomized trial conducted by Van
den Berghe compared traditional insulin therapy (treat
>215 mg/dL) to intensive insulin therapy (80-110
mg/dL) and the study showed a significant reduction
in morbidity and mortality in intensive care patients
significantly reducing in-hospital mortality from 11
to 7 percent in the entire study population42,43. In a
subgroup of patients who stayed in the ICU for three
or more days, however, the benefit was much more
pronounced, reducing mortality from 21 to 14 percent
among patients treated for at least three days and
from 26 to 17 percent among those treated for at least
five days. Severe complications such as sepsis and
organ failure were reduced. Similarly, Lazar showed
that tight glycemic control in coronary artery bypass
graft patients improved perioperative outcomes and
was linked to reducing recurrent ischemic events41.
However, intraoperative data regarding glycemic
control is limited to two retrospective studies of diabetic
patients undergoing cardiac surgery and demonstrate
an association between poor intraoperative glycemic
control and morbidity and mortality2,45.
195
Pharmacologic Considerations
Muscle Relaxants
The use of muscle relaxing agents such as
succinylcholine may be used safely in patients with renal
insufficiency provided they do not have high baseline
serum levels of potassium, since typically there is a
transient increase as high as 0.5mEq/L. For this reason,
it is inadvisable to use succinylcholine in end-stage
renal failure patients unless they have been dialyzed
within 24 hours. Close monitoring of train-of-four nerve
stimulation allows the clinician to accurately assess the
degree to which renal impairment may be affecting drug
pharmacokinetics. Rocuronium is another option that
can be used as a muscle relaxing agent in a patient with
renal disease. Rocuronium is primarily metabolized
hepatically and therefore should be used with caution in
patients with significant hepatic dysfunction.
Barbituates
The action of thiopental, a rapidly acting
barbiturate, is terminated by redistribution and is not
affected by renal impairment. However, in patients
with severe renal dysfunction (glomerular filtration rate
[GFR] <10) 75% of the normal dose is recommended
because of accumulation of an active metabolite.
Benzodiazepines
All drugs in this group are extensively metabolized
in the liver and are not affected by renal impairment.
Opiates
Morphine has one potentially significant
consideration in renal insufficiency. One of its
metabolites, morphine- 6-glucuronide, is cleared by the
kidney. This metabolite possesses opiate activity. For
this reason, if utilized, the dose of morphine should be
reduced to 75% of the standard dose in patients with a
GFR of 10 to 50 mL/min, and 50% of the usual dose in
patients with GFR under 10 mL/min. Meperidine, like
morphine, has an active metabolite, normeperidine.
However, unlike the metabolite of morphine, this
molecule exerts an excitatory CNS effect. Therefore, if
meperidine is used, doses should be decreased by 50%
in patients with a GFR of 10 to 50 mL/min, and 75%
with a GFR of less than 10 mL/min.
M.E.J. ANESTH 20 (2), 2009
196
Fentanyl is an attractive choice for patients
with renal dysfunction as it is primarily metabolized
in the liver. CYP3A4 is the major catalyst involved
in fentanyl oxidation to norfentanyl in human liver.
Alterations in CYP3A4 levels or activity, as well as
the concomitant administration of other therapeutic
agents metabolized by this P450 enzyme, could lead
to marked perturbations in fentanyl disposition and,
hence, analgesic response.
Conclusion
The prevalence of diabetes mellitus worldwide
requires each anesthesia provider to be well versed
in the drugs that are available in its treatment as
well as to appreciate the potential complications in
the perioperative management of these patients. It is
certain that over the coming decades newer modalities
will exist in the treatment of this very common disease
state. As these treatments became available and as there
is increasing understanding of the pathophysiology
of diabetes mellitus, the clinical anesthesia provider
must continue to educate themselves to ensure the
best outcome for this ever growing segment of our
population.
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Diagnosis, prevention, and treatment. Diabetes Care; 2005, 28:164.
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M.E.J. ANESTH 20 (2), 2009
sCiENTIFIC ARTICLES
THE IMPACT OF INTRAOPERATIVE
TRANSOESOPHAGEAL ECHOCARDIOGRAPHY
ON DECISION-MAKING DURING CARDIAC SURGERY
S. Mahdy*, B.O. Brien**, D. Buggy** and M. Griffin**
Summary
Backgrounds: Real time intraoperative transoesophageal echocardiograpgy (TOE) has an
expanding role in peri-operative management and surgical decision making.
Objectives: Studies of the effect of transoesophageal echocardiography (TOE) on intraoperative decision making commonly emphasise major changes in operative plans. We examined
more subtle effects using a novel scale, recording influences on management as follows:
Level 1: TOE had no effect on management, confirmed and quantified known pathology.
Level 2: TOE altered hemodynamic and /or anesthetic management.
Level 3: TOE evaluated the adequacy of surgical intervention /or repair.
Level 4: TOE led to an alteration in the surgical plan.
We compared the impact of TOE as an aid to intra-operative management in coronary artery
bypass cases with other types of cardiac surgery.
Methods: Retrospective, observational study in a single centre, university-affiliated hospital
included 319 patients undergoing cardiac surgery and suitable for TOE. TOE was performed in
each patient before and after the institution of cardiopulmonary by-pass. Normal and abnormal
echocardiographic findings as well as immediate outcomes of the surgical procedure were recorded
using a standard database form. Instances where TOE lead to alteration in operative management
were documented. The findings were also compared with those documented on preoperative
echocardiography.
Results: In 141 CABG patients TOE had a level 1 impact in 73%, level 2 impact in 11.6%,
levels 3 and 4 in 7% and 7.8% respectively. In 178 non CABG patients these values were 2%,
1.6%, (p <0.05), 72.4% (p <0.05) and 23.6% (p <0.05) respectively.
Conclusion: The impact of TOE in CABG procedures, while significantly less than that in
non-CABG surgical procedures, remains substantial.
Keywords: Transoesophageal echocardiography; outcomes; monitoring.
From Department of Anaesthesia, Intensive Care and Pain Management, Mater Misericordiae University Hospital, Eccles Street,
Dublin 7, Ireland.
*
Fellow in Cardio-thoracic Anaesthesia.
** Consultant Anaesthetist.
Correspondence to: Dr Saad Mahdy, MB BCh, MSc, FCARCSI, Department of Anaesthesia, Intensive Care and Pain
Management, The Mater Misericordiae Hospital, Eccles Street, Dublin 7, Ireland. Telephone: 00353-1-8032286, Fax
00353-1-8039563, E-mail: [email protected]
199
M.E.J. ANESTH 20 (2), 2009
200
Introduction
Apart from its role as a monitoring device,
transoesophageal echocardiography (TOE) influences
real-time intra-operative management and surgical
decision-making1,2. This role continues to expand.
The usefulness of TOE in certain categories of cardiac
surgery and, particularly, for the investigation of
hemodynamic instability, is widely accepted2-3. In the
setting of routine coronary artery bypass graft (CABG)
surgery it has a controversial role, this being considered
a class 3 indication for TOE3,4,5.
In our institution, intraoperative TOE is performed
in all complex cardiothoracic surgical patients, unless
contra-indicated. It is also used in many patients with
relatively “weak” indications most commonly coronary
artery bypass graft (CABG) surgery in patients with
good ventricular function.
While certain studies can be cited in support
of using TOE routinely3,5, there is also the need for
echocardiography trainees to become adept in the
conduct of routine TOE examinations and to become
familiar with normal anatomy and its variants. It is
difficult to compare the institutional benefit accruing
to trainees in gaining experience from such studies
with the clinical assessment of the risk-benefit to the
individual patient.
Although various authors describe differing
impacts from TOE in “routine” cardiac surgery, the
evidence-base for this application of the technology
is accumulating. Supportive data based on the ability
of TOE to influence management3,5, its safety [6] and
its benefits in planning surgery7 exist, but nonetheless
such widespread use must be carefully monitored and
justifiable. We therefore examined the database of our
Cardiothoracic Anaesthesia Fellows working under the
supervision of Cardiothoracic Anaesthesia Consultants
trained and certified in perioperative TOE, in order to
assess the impact of TOE on intra-operative surgical
and anesthetic decision-making in our institution,
a university-affiliated, tertiary referral hospital for
cardiothoracic surgery.
Methods and Materials
After approval of the Research and Ethics
Committee in Mater Misericordiae University
S Mahdy et. al
Hospital and getting patients permission to submit
their data for publication, we examined the records
of our Cardiothoracic Anesthesia Fellows through
a 24-month period, analysing all reported TOE
studies between July 1, 2005 and June 30, 2007. All
reports were compiled at the time of the study being
performed and completed at the end of each case.
All examinations were supervised by a Consultant
Cardiothoracic Anaesthetist with EACTA or NBE
Certification in Perioperative Echocardiography.
Studies were based on the systematic examination
recommended by ASA/SCA guidelines for
performing a comprehensive intraoperative multiplane
transoesophageal echocardiography examination4. The
majority of patients had preoperative transthoracic
echocardiography trans thoracic echocardiography
(TTE) performed by the Cardiology team. Six cardiac
surgeons participated in the study.
We classified the cases as, either CABG or
“other cardiac surgical procedures”, and recorded
the details of the type of procedure. Each Fellow
systematically recorded positive and negative (normal)
echocardiographic findings as well as immediate
outcomes of the surgical procedure using a standard
database form [see Appendix]. The results were then
tabulated in an Excel spreadsheet.
Mitral regurgitation was evaluated using colour
flow mapping (absolute jet area measurement and jet
area relative to left atrial size); evaluation of Pulmonary
venous flow by Pulse Wave Doppler and by Proximal
Isovelocity Surface Area Measurement when required.
Phenylephrine was used to normalize arterial pressure
to assess cases of mild MR8,9,10,11.
Mitral stenosis was evaluated using measurement
of velocity of diastolic blood flow using Continuous
Wave Doppler converted to a pressure gradient using
the Bernoulli equation; by planimetry when possible; by
measurement of the Pressure half-time and deceleration
time of the e wave; occasionally, when required, using
the Continuity Equation or the Proximal Isovelocity
Surface Area Measurement9,10,11.
Aortic regurgitation was assessed using size
of jet origin with Colour Flow mapping relative to
aortic root diameter; measurement of the slope of
Aortic Regurgitant jet decay or pressure half time
measurement and, when required, calculation of
THE IMPACT OF INTRAOPERATIVE TRANSOESOPHAGEAL ECHOCARDIOGRAPHY ON DECISION-MAKING
DURING CARDIAC SURGERY
regurgitant volume. Aortic stenosis was evaluated
using direct planimetry; measurement of velocity of
blood flow using Continuous Wave Doppler converted
to a pressure gradient using the Bernoulli equation;
and also by the Continuity equation12,13,14.
Patients were followed until extubation and for
one post operative visit following discharge from ICU.
Clinically detected esophageal injuries and any other
associated morbidity were recorded on the data sheet.
We retrospectively examined each case and quantified
the impact of TOE according to a novel scoring system,
as follows:
Level 1: TOE had no effect on management or confirmed
and quantified any known pathology.
Level 2: TOE altered the hemodynamic and /or
anesthetic management.
Level 3: TOE evaluated the adequacy of surgical
intervention or repair.
Level 4: TOE led to an alteration in the surgical plan,
i.e. an unplanned surgical intervention being
performed, or the cancellation of a planned one.
Patients were allocated a score corresponding
to the maximum benefit or impact attributable to
TOE during the case (as some patients had more than
one impact.) We also compared results and case-mix
reported by the three cardiothoracic fellows. Finally, as
TOE offers the ability to detect unanticipated cardiac
pathologies, we recorded instances where there were
new findings documented during surgery and how
these influenced management.
The level of practice change dictated by TOE in
CABG and non-CABG patients was compared using
χ2 analysis of contingency tables. P <0.05 is indicated
as significant.
Results
In the time period studied, 319 supervised intraoperative TOE studies were performed: (141 CABG,
and 178 non-CABG). The total number of CPB cases
over the time period was 1021.
The impact of TOE on intra-operative decisionmaking is shown in Table 1. Of the 141 CABG patients,
104 examinations were deemed to have Level 1 impact,
16 had Level 2 impact, 10 had Level 3 impact and 11
had Level 4 impact. Of the 178 non-CABG patients,
4 had Level 1 impact, 3 had Level 2 impact, 129 had
201
Level 3 impact and 42 had Level 4 impact (Table 1).
Table 1
Level of practice change dictated by TOE in CABG and nonCABG patients. All values shown
are %. P values calculated by χ2 analysis of contingency tables
Level
CABG cases %
Non-CABG cases %
P value
1
73
2
P=0.008*
2
11.6
1.6
P=0.18
3
7
72.4
P=0.01*
4
7.8
23.6
P=0.11
Table 2 shows the range of non-CABG surgeries
performed in this series. Most of these cases are
of valvular heart disease with a wide variety of
miscellaneous indications for TOE also described. We
also recorded the results reported by the three different
TOE fellows, showing a consistent level of impact.
Table 2
Non-coronary artery bypass graft cases. Adult Congenital
heart disease cases included surgery for ventricular septal
defect (VSD), atrial septal defect (ASD), Sinus venosus,
Ross procedures and Pulmonary artery (PA) homografts.
Miscellaneous cases include: pericardial windows, pericardial
tamponade, ascending thoracic aortic surgery, ventricular
assist device (VAD) insertion, cardiac tumours, TOE guided
intra-aortic balloon pump (IABP) insertions, nephrectomy for
renal cell carcinoma (RCC) and inferior vena cava thrombus
extraction
Aortic valve repair/replacement
42
Mitral valve repair/replacement
31
Combined valve surgery
27
Combined CABG + valve surgery
46
Adult congenital heart surgery
20
Miscellaneous
12
Total
178
Table 3 documents the incidence of clinically
significant unanticipated TOE findings in our patient
population. The most common were patent foramina
ovale (PFO) (in 46 cases), mitral valve abnormalities
(in 26), and aortic incompetence (in 12 cases). Two
of the PFOs were repaired. 16 of 26 cases of Mitral
Valve regurgitation secondary to annular dilatation
or leaflet prolapsed/flail were repaired. Even though
usually mild or trivial, the aortic incompetence was
significant enough to lead to changes in cardioplegic
technique in 3 patients, and aortic valve replacement
in one instance.
M.E.J. ANESTH 20 (2), 2009
202
S Mahdy et. al
TOE also offered benefits in the post-cardiopulmonary bypass period. In particular it allowed
detection of excessive air requiring prolonged de-airing
and additional de-airing manoeuvres (in 28 patients)
and of new regional wall motion abnormalities (in 9
patients, 2 of whom required re-institution of by-pass,
the others needing the institution of increased inotropic
support). TOE also facilitated correction of IABP
positioning (7 cases), detection of perivalvular leak (2
cases) and VSD post AVR (1 case).
Table 3
Unexpected clinically significant transoesophageal
echocardiography findings pre and post cardiopulmonary
bypass in our patient population
Pre bypass events
PFO
MV prolapse /flail
46 cases ( 2 repaired)
26 cases ( 16 repaired)
Aortic valve
incompetence
12 cases
1 case required AVR
3 cases changed cardioplegic
techniques
2 cases
Mean gradient <20mmHg, good
LVF, calculated aortic valve area
1.9 cm2
26 cases
Aortic stenosis
Tricuspid
incompetence
Aortic atheroma
Endocarditis
LAA thrombus
Total events pre bypass
19 cases
Altered aortic cannulation site in
11 cases
2 cases had OPCABG
2 cases had femoral cannulation
1 case
Unexpected PV endocarditis
required repair
1 case
Surgically removed
133 new findings
Post bypass events
VSD
PVL (perivalvular
leak)
Correction of IABP
positioning
Regional wall motion
abnormalities
1 case
VSD Post AVR required re-bypass
2 cases
1 required re-bypass, other
disappeared after protamine
7 cases
9 cases
2 required re-bypass
7 required conservative
management
Prolonged de-airing
28 cases
Total post bypass events 47
Only one complication was recorded. In this case
of oesophageal ulceration was identified 10 days postoperatively, and attributed to the passage of the TOE
probe. In one other case, there was failure to pass the
probe, which caused no morbidity.
Discussion
Transoesophageal echocardiography (TOE)
is fundamental to modern cardiothoracic surgical
and anesthetic practice, providing real-time data
on hemodynamic and cardiovascular function in a
minimally invasive manner, that can demonstrably
impact on management1,2,3. Efforts to quantify
the contribution this technology makes to patient
management and decision-making tend to emphasise
major changes being made to operative plans15.
While obviously very important, these are relatively
uncommon, with their frequency varying depending
on the group and institution studied (most obviously
with the quality and extent of preoperative workup).
The American Society of Anesthesiologists
and the Society of Cardiovascular Anesthesiologists
Task Force on Transoesophageal Echocardiography,
following a consensus conference, has recommended
guidelines for the use of TOE in clinical practice4.
They stratified the indications for its use as categories
1 to 3, with category 1 indications for TOE being
the best validated i.e. where compelling scientific
evidence suggests that it improves clinical outcome
and its use is widely accepted on the basis of that
evidence. Examples of category 1 indications for TOE
are valve repairs and surgical resection of hypertrophic
obstructive cardiomyopathy. Category 2 indications
are less well supported by evidence, but the use of
TOE in this group does benefit a significant proportion
of patients. For example, one series, which compared
category 1 and 2 indications, found that 28% and 14%
of patients benefited, respectively5.
The present study had two objectives. Firstly,
we aimed to assess the contribution of TOE to the
management of our CABG patient population and to
compare its impact in this group with that in a group
of patients in which its use is well established and
accepted. In 16 CABG patients (11.6%) there was
level 2 impact, 10 (7%) demonstrated Level 3 impact
and 11 (7.8%) Level 4 impact. Our results therefore
suggest that in our institution there was a significant
impact on the management of our CABG patients and
strengthens the case for more widespread use of TOE
in high risk CABG patients.
Secondly, we aimed to measure the frequency
and significance of unanticipated TOE findings in our
patient population. Two of the PFOs were repaired
intraoperatively. The decision to repair is complex
and patient specific, depending on the hemodynamic
effect, the size of the defect, age of the patient, history
of potential embolic events and the type of cardiac
surgery being performed16.
There are several previous studies addressing
perioperative echocardiography in the CABG
population of patients[3,5,7,15,17,18,19. Savage et al studied
82 high risk CABG patients17, and demonstrated that
TOE lead to changes in the surgical plan in 33% and
alteration of anesthesia and hemodynamic management
in 51% of patients, results are similar to ours. Sutton
et al18 studied 238 adult patients for cardiac surgery
(136 patients in CABG and 102 non CABG) and
demonstrated potentially important new diagnostic
information detected in 21% of routine studies and in
54 out of 55 requested examinations. Overall, TOE led
to a change in surgical plan in 6% of patients. This
is only partly explained by the fact that there were
relatively more CABG cases in this report compared
to our study: their overall impact (for all cases, both
CABG and non-CABG) is lower even than our CABG
group which illustrates the potential for marked
variation between institutions, especially with regard
to the extent of preoperative work-up and the reliance
of surgeons on intraoperative TOE. That this study
was performed when intraoperative TOE was less well
established may be part of the explanation, as perhaps
experience with the technology was not as great as it
is today, reflecting the ability of technology to grow in
impact over time.
The fact that most previous published studies
have emanated from the USA is a significant
factor given that preoperative workup, in particular
echocardiography, is more extensive there than in
Ireland or the UK. The more recent report of Canthy et
al19 of a large prospective study from UK had findings
more similar to ours, intraoperative TOE led to changes
in the surgical plan in 21% of patients. In half of those
203
cases a planned procedure was cancelled and in the
other half an additional procedure was added, all of the
latter being valve surgeries.
Making echocardiographic judgements in
anesthetised supine patients is not ideal given the
altered loading conditions. However, vasopressors and
inotropes can be given to mimic normal physiological
conditions and the willingness to change treatment plan
based on intraoperative echocardiography findings
should be coloured by the adequacy of the preoperative
work up.
Coronary artery bypass grafting (CABG)
constitutes a category 3 indication for TOE, with a
weak evidence base for its routine application in this
setting4. Obviously, this means that it less frequently
alters decision-making or impacts on patient outcome.
It is difficult, however, to gain competence and
experience in intraoperative TOE without studying the
CABG patient group who make up a large component of
everyday cardiac surgical throughput. In our institution
we use TOE in high risk CABG patients, provided that
it is not contra-indicated, and is logistically feasible.
This ensures that our Cardiothoracic Anaesthesia
Fellows gain adequate experience, and also that
those with experience maintain it. However, our data
suggests that this group of patients in our institution
do benefit from this approach. Not all patients have
comprehensive
pre-operative
echocardiography
performed, particularly emergent cases or cases
transferred semi-urgently from other institutions.
Over time, our cardiothoracic surgeons have come to
rely on the intraoperative echocardiographic findings
particularly in these situations.
There are limitations to the present study. That
it is a single-centre study and reports the experiences
of a small number of investigators are amongst the
most obvious. The retrospective nature of the analysis
is another shortcoming. The variable quality of preoperative echocardiographic evaluation – which can
be absent in emergency cases – is also an issue.
Conclusion
In summary, we compared the benefit of
intraoperative TOE examination in CABG patients
with non-CABG patients in our institution. We
M.E.J. ANESTH 20 (2), 2009
204
S Mahdy et. al
quantified the impact of TOE using a novel scoring
system. Our results suggest that our CABG patient
population benefits from intraoperative use of TOE
perhaps to a greater extent in our institution than in
many previously published studies and that the level
of impact is highly reproducible between different
echocardiographers. In addition, we found significant
benefits from incidental or unexpected TOE findings
both pre and post cardiopulmonary bypass in our
patient population.
APPENDIX
205
M.E.J. ANESTH 20 (2), 2009
206
S Mahdy et. al
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S8-S9.
EFFECTS OF SEVOFLURANE ON POSTOPERATIVE
LIVER FUNCTIONS IN MORBIDLY OBESE AS
COMPARED TO THE NON-OBESE PATIENTS
Subhi M Al-Ghanem*, Islam M Massad**,
Bassam Al-Barazangi***, Mahmoud Al-Mustafa****,
Fayez S Daoud***** and Hamdi Abu-Ali******
Abstract
Objective: To assess the effect of sevoflurane anesthesia on hepatic function in morbidly
obese versus non-obese patients undergoing abdominal surgeries.
Methods: We prospectively evaluated the levels of the serum concentration of liver enzymes
aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH),
gamma glutamyl transferase (GGT), alkaline phosphatase (ALP), and total bilirubin (TBil), in 42
morbidly obese and 40 non obese patients who were scheduled for elective abdominal surgery
under sevoflurane anesthesia at the Jordan University Hospital, Amman, Jordan. Measurement
of liver enzymes was done in the recovery room, and on the first, 3 and 7 days after sevoflurane
anesthesia, and the results were compared between the morbidly obese and non obese patients.
Results: ALT, AST, GGT and LDH increased significantly in the morbidly obese than they
did in non obese patients. In morbidly obese patients TBil increased gradually peaking 7 days after
anesthesia, LDH increased in the recovery room, AST and ALT increased in the recovery room and
first day, while GGT increased 7th day after anesthesia. In non obese patients, AST, LDH increased
in the recovery. ALP did not change in both groups.
Conclusion: Sevoflurane induces elevation of the serum liver enzymes in morbidly obese
patients with variable onsets.
Keywords: Sevoflurane, Liver enzymes, morbid obesity.
From Faculty of Medicine, Univ. of Jordan, Amman, Jordan,
Dept. of Anesthesia & IC.
*
FFARCS, Assoc. Prof.
** MD, Assoc. Prof.
*** FFARCSI, Assoc. Prof.
****MD, Assist. Prof.
Dept. of General Surgery.
***** FRCS, Prof.
****** MD, Research Follow.
Corresponding author: Dr. Subhi M Al-Ghanem, Associate Professor of Anesthesia and Intensive Care, Faculty of Medicine
and Jordan University Hospital. P.O. Box: 13046, 11492 Amman, Jordan, E-mail: [email protected]
207
M.E.J. ANESTH 20 (2), 2009
208
Introduction
Postoperative hepatic injury has been reported
after exposure to volatile anesthetics especially
halothane, and female, obese middle-aged women
are more affected than males1-8. The injury is usually
seen few days after exposure and is characterized by
malaise, fever, jaundice, eosinophilia and marked
elevation in serum transsaminases which occasionally
ends with massive liver necrosis and death9.
Sevoflurane is comparatively recent addition
to the range of inhalational anesthetics. It has a low
blood solubility which results in rapid induction
and faster recovery10. Although there are reports of
sevoflurane-associated liver injury in the literature1114
, sevoflurane is considered less hepatotoxic than the
older inhalational agents15,16. Several studies reported
the effects of sevoflurane anesthesia on postoperative
liver functions in surgical patients17-19, however, there
are no reports on the effects of sevoflurane on liver
functions in morbidly obese patients. The aim of
this study was to compare postoperative serum liver
enzymes in morbidly obese and in non obese patients
undergoing elective abdominal surgeries under
sevoflurane anesthesia.
Patients and Methods
After Institutional Review Board approval,
informed consents were obtained from 82 (40 nonobese and 42 morbidly obese) ASA I or II 16-68 old
patients scheduled for the first time elective abdominal
surgery at the Jordan University Hospital, Amman,
Jordan. Patients who received anesthetics in the last
three months, who had received drugs that induce liver
enzymes and who had liver diseases, were excluded
from the study. Patients who were reoperated or
suffered from wound infection were also excluded
from the study.
Patients were not premedicated. Anesthesia was
induced with propofol 1.5-2.5 mg/kg in a dose sufficient
to abolish eyelash reflex and remifentanil 1 µg/kg.
The dose of propofol was correlated to the lean body
weight. Atracurium 0.5 mg/kg or cisatracurium 0.15
mg/kg were used to facilitate endotracheal intubation.
Anesthesia was maintained with 1-3% sevoflurane
inspired concentration in air and oxygen with a total
Subhi M Al-Ghanem et. al
fresh gas flow of 6-10 l/min. Intraoperative analgesia
was maintained with 0.1-02 µg/kg/min of remifentanil.
The anesthetic concentration was adjusted to maintain
systolic blood pressure ± 20% of the baseline value.
Controlled ventilation was adjusted to maintain PaCO2
between 30-40 mmHg.
All patients were extubated after surgery in the
operating room. Prophylactic doses of a third generation
cephalosporins antibiotic and Metronidazole were
restricted to three grams and 1500 mgs respectively.
Patients received prophylactic heparin 5000 IU daily
for prevention of deep venous thrombosis. Pethidine
was used for post operative analgesia.
Serum levels of aspartate aminotransferase
(AST), alanine aminotransferase (ALT), alkaline
phosphatase (ALP), lactate dehydrogenase (LDH),
gamma glutamyl transferase (GGT) and total bilirubin
(TBil), were measured before, in the post anesthesia
recovery room and 1, 3, 7 days after anesthesia, using
the antecubital vein for venous blood sampling and the
analysis were performed in duplicate.
The MAC. hour exposure to sevoflurane was
calculated from the percent anesthetics concentration
and the duration of exposure. MAC value of 2% for
sevoflurane was used10.
All statistical analysis was carried out using Stat
graphics Centurion xv (version 15.1.02), (Statpoint, Inc
2006). All values are expressed as means and standard
deviations. Multiple sample comparison method was
used to study the different variables. The mean for
each value was calculated and the standard deviation
was also documented. The age, BMI, mean duration
of surgery and exposure to sevoflurane (MAC. Hour)
were compared between the two groups (obese and
non-obese) using the t-test and Fisher’s least significant
difference (LSD). For the serum liver enzymes level,
the means for the level at pre-surgery, recovery, 1, 3
and 7 days were measured in the two groups. The presurgery level of enzymes was compared to the level
at recovery, 1, 3 and 7 days in each group and then
compared between the 2 groups using analysis of
variance, ANOVA. An asterisk (*) has been placed next
to several values, indicating that these values when
compared to their pre-surgery values, show statistically
significant differences at the 95.0% confidence level. A
mark (†) has been placed to show a statistical difference
EFFECTS OF SEVOFLURANE ON POSTOPERATIVE LIVER FUNCTIONS IN MORBIDLY OBESE AS COMPARED
TO THE NON-OBESE PATIENTS
between the obese and non-obese patients. A p <0.05
was considered statistically significant.
Results
There was no difference between the two groups
with regard to age, sex and duration of anesthesia
(Table 1).
Table 1
Demographic Data
Age (years)
Non-obese
Morbidly Obese
40.2 (12.8)
36.8 (12.3)
Male/Female
5/35
12/30
BMI (kg/m2)
26.7 (3.4)
46.2 (7.1)
2.59 (0.86)
while GGT increased significantly 7 days after
anesthesia (Table 2).
LDH, AST and ALT had their peaks in the
post anesthesia recovery room decreasing gradually
towards the 7th day. There was no increase in ALP
during the study period. In morbidly obese patients,
TBil reached 2 mg/dL in one patient, LDH values of
900 to 2110 IU/L were observed in 7 patients and AST,
ALT values of 200 to 660 IU/L were also observed in
4 patients. In non obese patients AST, LDH increased
in the recovery period. There was no post operative
hepatitis or liver failure.
Discussion
Duration of anesthesia (min) 139.4 (45.8) 147.2 (49.3)
Exposure to sevoflurane
(MAC. hr)
209
3.01 (1.4)
Values are mean (SD); BMI: body mass index; MAC: minimal
alveolar concentration.
AST, ALT, GGT and LDH increased significantly
in the morbidly obese as compared with non morbidly
obese patients. In morbidly obese patients, TBil
increased gradually peaking 7 days after anesthesia,
The results of this study showed that when using
Sevoflurane, serum concentrations of LDH, GGT,
AST and ALT were significantly higher in morbidly
obese patients than in the non obese patients. Several
studies demonstrated that liver enzymes are elevated
after sevoflurane anesthesia17-19. Although several
mechanism were postulated to result in this elevation
of liver enzymes, none of them alone is responsible for
this elevation.
Table 2
Serum levels of liver enzymes
Days after Anesthesia
Enzyme
Pre
Recovery
1
3
7
ALP
Non-obese
76.3 (24.1)
71.5 (21.5)
69.0 (22.0)
72.8 (21.8)
72.9 (25.4)
Up to 100 (IU/1)
Morbidly obese
84.0 (26)
76.1 (22.6)
71.9 (23)
67.5 (22.7)
82.4 (40)
ALT
Non-obese
22.0 (13.1)
20.7 (10.3)
23.3 (16.5)
25.4 (21.8)
22.2 (10.6)
up to 40 (IU/I)
Morbidly obese
27.5 (15)
92.7 (114)†*
78.76 (107)†*
49.6 (46.8)†
39.7 (32.0)
AST
Non-obese
21.1 (7.0)
27.2 (17.2)*
25.2 (12.4)
26.6 (13.1)
24.0 (9.1)
up to 40 (IU/I)
Morbidly obese
26.2 (13.5)†
95.7 (87.7)†*
66.8 (82)†*
44.7 (46.8)†
35.0 (21)†
GGT
Non-obese
21.5 (16.5)
19.9 (15.3)
23.4 (22.9)
27.2 (24.4)
26.1 (25.8)
up to 40 (IU/I)
Morbidly obese
28.9 (20)
29.2 (19)
29.3 (22.6)
31.6 (18.4)
47.0 (38.0)†*
LDH
Non-obese
317.3 (97.1)
381.7 (137.8)*
369.3 (137.0)
up to 330 (IU/I)
Morbidly obese
453.6 (113.0)
661.6 (319.0)
504.2 (221.0)
TBil
Non-obese
0.9 (1.6)
0.6 (0.3)
0.8 (0.6)
0.7 (0.3)
0.6 (0.2)
up to 1.4 mg
Morbidly obese
0.5 (0.2)
0.6 (0.2)
0.7 (0.3)*
0.8 (0.5)*
0.8 (0.9)*
†
†
†*
†
352.8 (117.8)
325.1 (86.6)
525.7 (138)
499.3 (151)†
†
(mg/dl)
Values are mean (SD); *: P <0.05 vs. the control value (pre); †: P <0.05 non-obese vs. obese; pre: before anesthesia; recovery: post
anesthesia recovery room; TBil: total bilirubin; LDH: lactate dehydrogenase; GGT: gamma glutamyl transferease; AST: aspartate
aminotransferase; ALT: alanine aminotransferase; ALP: alkaline phosphatase.
M.E.J. ANESTH 20 (2), 2009
210
Factors implicated in liver injury after exposure to
inhalational agents include reduction in hepatic blood
flow, metabolites of the anesthetics and increase in
intracellular calcium20-24. Halothane can reduce hepatic
blood flow and can result in hepatic cells injury20,21. In
the case of Sevoflurane, there is conflicting evidence
whether it reduces hepatic blood flow in humans25-27.
The effects of metabolites of inhalational
anesthetics as a mechanism explaining liver injury
has been extensively studied especially those of
halothane.
Trifluroacetyl acid (TFA) is a common oxidation
metabolite of halothane, enflurane, desflurane and
isoflurane and this compound reacts with subcellular
hepatic cells proteins and produces new proteins which
in certain individuals induces immune response and
liver injury24.
Two to 5% of inhaled sevoflurane in metabolized
in humans10. The main metabolite of sevoflurane
is hexafluoroisopropanolol (Compound A), this
compound does not react with liver cell protein and
does not produce liver cell injury29,30. Sevoflurane
reacts with CO2 absorbents and produces compound
A, a compound that is nephrotoxic in a dose related
manner in rats28. In our study we used fresh gas flow
6-10 L/min were the concentration of compound A is
Subhi M Al-Ghanem et. al
negligible in the anesthesia breathing circuit with the
high fresh gas flow used.
The mechanism of sevoflurane-associated
hepatic injury seems to be unclear. Four cases of
hepatic injury after exposure sevoflurane have been
reported in Japan11-14. Toxic metabolites of sevoflurane
may explain these injuries since sevoflurane has been
found to induce liver enzymes in rats30.
There are no reports about the effects of
sevoflurane on intracellular Ca++, whereas halothane
and enflurane release intracellular calcium which may
increase hepatic cells injury23.
The changes in liver enzymes in this study
were statistically significant but were not clinically
significant in any patient. Although the effect of other
drugs given to patients on the post operative liver
enzymes levels cannot be excluded, there is no evidence
that these drugs elevate serum liver enzymes31.
In conclusion Sevoflurane anesthesia is
associated with a transient increase in liver enzymes
in morbidly obese patients. This enzymatic elevation
was without the occurrence of postoperative hepatitis
or liver failure; and was of statistical but not of clinical
significance. The mechanism of action of the increased
lever enzymes is not clear.
EFFECTS OF SEVOFLURANE ON POSTOPERATIVE LIVER FUNCTIONS IN MORBIDLY OBESE AS COMPARED
TO THE NON-OBESE PATIENTS
211
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sevoflurane anesthesia in a child. Masui; 1991, 40:1542-1545.
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hepatic injury after sevoflurane anesthesia. Masui; 1992, 41:18021805.
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Hanoks MD PhD: Liver function after sevoflurane or isoflurane
anaesthesia in neurosurgical patients. Can J Anaesth; 1998, 45:8,
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D: Hepatic blood flow in humans during isoflurane - N2O and
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of volatile anesthetics on Ca++ mobilization in rat hepatocytes.
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blood flow during anesthesia in man. Masui; 1994, 8:55-59.
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M.E.J. ANESTH 20 (2), 2009
PATIENT SURVEY OF CONTINUOUS
INTERSCALENE ANALGESIA AT HOME
AFTER SHOULDER SURGERY
Elie J Chidiac*, Roland Kaddoum**
and S teve A P eterson ***
Brief summary statement for table of contents: Patients who went home with continuous
interscalene analgesia at home were surveyed for quality of analgesia, catheter site infection,
clear fluid leakage, premature catheter dislodgement, shortness of breath, residual neurological
symptoms and overall comfort with this method of postoperative pain control.
Abstract
Background: The use of continuous peripheral nerve blocks at home (CPNBH) has improved
patients’ perioperative experience. In 30 months, 348 patients were sent home with interscalene
CPNBH.
Methods: With the Institutional Review Board (IRB) approval, all patients were surveyed for
quality of analgesia and complications. The patients and their caretaker received verbal and written
instructions, including care of the catheter and pump, and a list of complications and side effects.
All were instructed on catheter removal and were given a contact number, and patients were called
once per day.
Results: 172 patients responded to this survey. The majority of patients (76%) had very good
postoperative analgesia. There was a 9.3% incidence of leakage of clear fluid, a 5.8% incidence
of premature dislodgement, and an 8.7% incidence of shortness of breath. Residual neurological
symptoms persisted in 18.6% of responders, all resolving within two months except in one case.
A large proportion (40%) required no oral analgesics, and half of the rest required less than 3 pain
pills. Most (94.1%) felt comfortable removing the catheters at home by themselves or by a family
member/caretaker.
Conclusion: This survey shows that CPNBH results in low pain scores and a low incidence
of side effects. Many patients commented positively on their overall impression of their anesthesia
care, particularly the level of attention that they received. This highlights the low incidence of those
complications and neural injury.
From Wayne State University, Detroit, Michigan, USA.
*
MD, Assistant Professor of Anesthesiology.
** MD, Anesthesiology Resident.
*** MD, Associate Professor of Orthopedics.
Correspondence: Roland Kaddoum, MD, Department of Anesthesiology, 3990 John R, Box 162, Detroit, MI 48201. Phone:
313 745 7233, Fax: 313 993 3889. E-mail: [email protected]
Financial support: Support was provided in part by the I-Flow Corporation, Lake Forest, CA and by the Department of
Anesthesiology, Wayne State University, Detroit, MI.
213
M.E.J. ANESTH 20 (2), 2009
214
Elie J Chidiac et. al
Introduction
Placement of continuous catheters near peripheral
nerves for postoperative pain control has been shown
to increase patient satisfaction1, decrease narcotic
requirements and resultant nausea and vomiting2,
improve quality of sleep2, accelerate the rehabilitation
process3, and decrease hospital costs4. At the Michigan
Orthopaedic Specialty Hospital, over 700 patients
have been discharged with continuous peripheral nerve
blocks at home (CPNBH). The majority have been
those undergoing shoulder surgery and receiving a
continuous brachial plexus catheter via an interscalene
approach. There is one article in the literature, based
on a telephone survey reviewing CPNBH from the
patients’ perspective, with 131 patients5. Of those,
only 22 had interscalene catheters. The purpose of this
retrospective study was to gather data on a larger patient
sample and evaluate the quality of pain control and
the frequency of side effects, particularly pulmonary,
neurological and infectious complications.
Materials and Methods
With approval from Wayne State University’s
Institutional Review Board, all patients were mailed
a letter and consent explaining the survey. Two weeks
later, all were mailed a questionnaire (Table 1).
Table 1
Survey Questions
1 - How well was your pain controlled during the continuous
infusion?
2 - Where there any catheter problems?
3 - Was there any infection, pus or drainage?
4 - Did you have any difficulty breathing?
5 - Did you have any residual numbness or tingling after
catheter removal? If yes, for how long?
6 - How many pain pills did you take while the catheter was
in place?
7 - When was the catheter removed?
8 - Did you feel comfortable removing the catheter at
home?
9 - Would you recommend this technique?
10 - Rate your overall satisfaction.
Between March 2003 and August 2005 (30
months), 378 interscalene catheters were inserted for
various shoulder procedures (Table 2).
Table 2
Types of surgeries
Types of surgeries
Total CPNB1
Survey responses
Open musculotendinous
repairs
86
33
Shoulder arthroplasties
78
37
Open shoulder capsular
repairs
39
26
Arthroscopic surgeries
148
65
Shoulder manipulation
27
under anesthesia
1 continuous peripheral nerve blocks.
11
Most were sent home with CPNBH (Table 3) and
30 were removed prior to discharge (Table 4). All 348
patients who went home with CPNBH were included
in this study.
Table 3
Outcome after surgery
Home on day-of-surgery with CPNBH1: 147
Home on POD#12 with CPNBH: 103
Home on PO#23 with CPNBH: 98
Catheter removed in-hospital prior to discharge: 30
1 continuous peripheral nerve blocks at home.
2 Post operative day one.
3 Post operative day two.
Table 4
Catheters removed prior to discharge
Ineffective pain relief: 9
Catheter inadvertently dislodged: 2
Excessive fluid leakage: 4
No pain with CPNB turned off: 4
Redness at site: 2
In-hospital till POD#31, so catheter removed as planned: 3
Shortness of breath: 4
Disliked feeling of numb hand: 2
1 Post operative day three.
After pre-procedure instructions to the
patient in the presence of their family member/
caretaker, patients were taken into a ‘block room’.
With noninvasive monitoring and after intravenous
sedation, all interscalene catheters were placed using
the modified lateral approach6,7. Stimulating catheters
(Stimucath®, Arrow International, Reading, PA)
were used for all cases. No solution was injected
through the needle. All catheters were threaded 4-5
cm beyond the needle tip with continuous stimulation
and tunneled subcutaneously toward the midline. Just
before securing the catheters, the patient’s family
member/caretaker was brought into the ‘block room’,
PATIENT SURVEY OF CONTINUOUS INTERSCALENE ANALGESIA AT HOME AFTER SHOULDER SURGERY
215
written instructions regarding the care of the catheter
and pump. This included a list of complications and
side effects, emphasizing catheter site infection, local
anesthetic toxicity, shortness of breath and hand
numbness. All were instructed on catheter removal and
were given a contact number for the anesthesiologiston-call. All patients were called once per day, including
the day after catheter removal, with a list of specific
questions (Table 5).
to observe the taping process and learn about removal
of the catheter. These were secured with Mastisol®
liquid adhesive (Ferndale Laboratories, Ferndale,
MI), SutureStripPlus® flexible wound closure strips
(Derma Sciences, Princeton, NJ) and covered with a
Tegaderm® (3M Corporation, St. Paul, MN). Catheter
hubs were attached to the contralateral chest wall with
a StatLock® (Venetec International, San Diego, CA).
After a test dose of local anesthetic with epinephrine, all
patients received an initial bolus through the catheter,
with 40 ml mepivacaine 1.5% with epinephrine
1:400,000.
Table 5
Daily telephone follow-up
What is your pain level?
Do you have any nausea and/or vomiting?
Are you too sleepy/too groggy?
Do you have any shortness of breath?
Is the catheter site leaking?
Is there any swelling, redness, or bleeding at the catheter
site?
What part of the limb is numb?
Is the “dead” feeling bothering you?
Any other concerns?
Additional questions after removal at home:
Were there any difficulties with catheter removal?
Did you see the silver-colored spring at the tip of the
catheter?
Prior to discharge, all patients received
prescriptions for a nonsteroidal anti-inflammatory
medication, an oral opioid and a stool softener. All
postoperative home infusions consisted of bupivacaine
0.125%. All disposable home pumps were manufactured
by I-Flow (Lake Forest, CA). Before March 2004, all
patients were sent home with a pump delivering a fixed
rate of 5 ml/hr, except those with adhesive capsulitis
of the shoulder who were scheduled for outpatient
physical therapy, as they received a pump with 5 ml/
hr and patient-controlled boluses of 5 ml with a 60minute lockout. After that date, patients with open
shoulder procedures were sent home with a variablerate pump capable of delivering a rate of zero to 14 ml/
hr, in increments of 2 ml/hr, at the patient’s discretion.
Results
Thirty catheters were removed prior to discharge,
because of the reasons listed in Table 4. Of the 348
patients who went home with CPNBH, 172 responded
Patients and their caretakers received verbal and
Table 6
Responses to survey
Total responses:
Age:
172
40 or less: 31
VAS during CPNBH:
Leaking: 16
Neurologic symptoms lasted:
Catheter removed:
POD # 0-11: 23
Comfortable removing catheter at home:
Overall satisfaction:
Very satisfied: 133
8-10: 13
Dislodged: 10
Residual neurologic
symptoms: 32
2-4 weeks: 6
By self or family: 170
1-3 pills: 51
Over 80: 6
4-7: 28
1 week or less: 19
None: 69
Female: 96
61-80: 61
Subjective feeling of shortness
of breath: 15
Catheter removal:
Pain pills used:
40-60: 74
0-3: 131
Catheter problems:
Other problems:
Male: 76
1-2 months: 6
Infection, pus, drainage: 0
More than 2 months: 1
By doctor: 2
4-6 pills: 29
7-10 pills: 14
More than 10 pills: 9
POD#2-42: 149
Yes: 162
No: 10
Somewhat satisfied: 25
Not satisfied: 14
1 Post operative day zero to one.
2 Post operative day two to four.
M.E.J. ANESTH 20 (2), 2009
216
to this survey, for a 49.4% response rate. Table 6 lists
their answers.
concentrations and drip rates, ropivacaine may have
resulted in less long-term neurologic sequelae.
The majority of patients (76%) had very good
postoperative analgesia. There was a 9.3% incidence
of leakage of clear fluid at the catheter site. Despite
this taping and anchoring technique, the catheters
were prematurely dislodged in 5.8% of cases. Fifteen
patients (8.7%) had a subjective feeling of shortness
of breath. Twelve hours after catheter removal, 32
patients (18.6%) had residual neurological symptoms,
including tingling, ‘pins and needles’ and numbness.
All resolved within two months, except one case. A
large proportion (40%) required no oral analgesics, and
half of those who took any breakthrough medications
required less than 3 pain pills. Most catheters (86.6%)
were removed between POD#2 and POD#4, and
most patients (94.1%) felt comfortable removing
the catheters at home by themselves or by a family
member/caretaker.
This series shows no cases of infection. However,
two patients had some redness at the insertion site
and had their catheters removed prior to discharge.
In the literature, there is a high incidence of catheter
colonization14,15, but only a total of five cases of
catheter infection after peripheral nerve blocks7,15-18,
four of whom were diabetic.
Discussion
This survey shows that CPNBH is safe, with
low pain scores and a low incidence of side effects.
A recent meta-analysis of nineteen randomized
controlled trials found that, compared to parenteral
opioids, CPNB analgesia results in statistically and
clinically significant improvements in pain control
and decreases the opioid-related side effects of nausea/
vomiting, sedation and pruritus8. With improvements
in the major anesthetic morbidities of death and
hypercoagulable states, there is a new focus on these
very issues, also called patient-centered nontraditional
outcomes, or ‘minor’ morbidities9.
Bupivacaine was chosen over ropivacaine
because of cost: At our Institution, there is a ten-fold
difference in the cost of 500ml ropivacaine 0.2%
versus 500ml bupivacaine 0.125% ($70.00 versus
$7.00 respectively). At these concentrations, the
argument for using ropivacaine is not its cardiac safety
profile, since the blood concentrations achieved with
this dilute bupivacaine are safe10. Instead, the issue is
that of neurologic sequelae: Ropivacaine preferentially
blocks sensory fibers over motor fibers11 and causes
less hand numbness with continuous interscalene
analgesia12. It is less myotoxic than bupivacaine in
bolus form13. However, it is unclear whether at these
The disposable home infusion pumps were all
from the same manufacturer (I-Flow, Lake Forest,
CA). It seems that a fixed rate of 5 ml/hr is adequate
for interscalene analgesia. After the rate-variable pump
became available, most patients used a setting of 4 or 6
ml/hr. Some chose to decrease the infusion rate in the
daytime, accepting mild discomfort but avoiding hand
numbness, and they would increase the rate at night,
so they can sleep without pain. There is no consensus
in the literature on the ideal infusion rate or the need
for intermittent boluses. The stimulating catheters may
allow for slower rates and therefore may render many of
the studies with nonstimulating catheters obsolete19.
The incidence of leakage of clear fluid was
9.3%. Adding the four cases of leakage among those
30 patients whose catheters were removed prior to
discharge, the incidence increases to 9.9%. This is
slightly lower than that reported by others2,5 and may
be related to the low rate of infusion with stimulating
catheters, or the ability to thread a stimulating catheter
further from the insertion site, or that tunneling
decreases leakage20.
The incidence of accidental dislodging of
catheters was 5.8% (increases to 5.9% by adding the
two that were dislodged while inpatient). This incidence
is lower than in previous reports5,15 and will probably
continue to decrease with the ongoing development of
new anchoring techniques and liquid adhesives.
Four catheters (1.05% of 378 patients) were
removed before discharge because of shortness of
breath, and fifteen patients (8.7%) had a subjective
feeling of shortness of breath. Unlike others15, no
patients developed acute respiratory failure requiring
admission to the intensive care unit. There are rare case
reports of pulmonary complications after continuous
interscalene blocks21,22. These may be related to phrenic
nerve paresis. A study using the paresthesia technique
PATIENT SURVEY OF CONTINUOUS INTERSCALENE ANALGESIA AT HOME AFTER SHOULDER SURGERY
found an incidence of 100% phrenic nerve paresis with
single-shot interscalene blocks23. Newer work shows
a lower incidence with the nerve stimulator technique
and an even lower incidence with injections through a
catheter24, perhaps because the latter allows injection
at a more distal site1. In the only study of the effects
of continuous interscalene analgesia with 0.125%
bupivacaine on pulmonary function, the infusion
was stopped after 24 hours, at which point ipsilateral
hemidiaphragmatic motility was at 50% of preoperative
values, yet pulmonary function tests (forced vital
capacity, forced expiratory volume in one second and
peak expiratory flow) were only decreased by 10%.
The author suggested that the loss of diaphragmatic
function on one side is compensated by all other
respiratory muscles, resulting in this minimal decrease
in pulmonary function25. Although there is no study
comparing the effects of CPNBH with bupivacaine and
ropivacaine on phrenic nerve and pulmonary function,
similar results have been found with ropivacaine, along
with the same compensatory increased activity of the
contralateral hemidiaphragm1.
Ilfeld and Enneking19 have pointed out that, in
the process of moving this method of pain control
from an in-patient to an outpatient setting, one must be
mindful of complications, as they may become more
difficult to treat at home. This is where the initial use of
mepivacaine 1.5% helps identify those patients where
respiratory compromise may become symptomatic. If
there is a complaint of subjective feeling of shortness
of breath, the block wears off sooner than with a longacting local anesthetic and the catheter can be removed,
thus avoiding a prolonged period of respiratory
compromise. There is another patient population who
benefits from using mepivacaine: Those undergoing
total shoulder arthroplasty, where there is a need to
assess the integrity of the brachial plexus after surgery.
The block is used to decrease intraoperative anesthetic
requirements and wears off early in the postanesthesia
recovery room where, after post surgical confirmation
of neuromuscular integrity, additional local anesthetics
can be given.
Thirty patients (18.5%) reported residual
neurological symptoms after catheter removal, with
complete resolution within two months in all except
one case. That patient had prolonged numbness in the
217
radial distribution, which resolved completely after 5
months. She had excessive numbness throughout the
infusion period and was not reached via telephone
until her fourth postoperative day. Typically, at this
Institution, patients with excessive hand numbness are
instructed to intermittently clamp the pump tubing.
As discussed above, it is unclear whether the use of
ropivacaine may have decreased this problem. This
neural deficit in one patient results in an incidence of
0.26%, similar to findings by others7,15. Preexisting
neurological deficits, perioperative positioning and
surgical traction may have contributed to this, in what
has been termed the ‘double-crush injury’26.
Ten patients (7.5%) reported they were “not
comfortable” removing the catheter at home, and
would have preferred to return to the hospital for this,
and two patients did return. This is similar to the results
of Ilfeld et al5, where two of their 22 patients (9%) with
interscalene catheters preferred to return for removal.
Fourteen patients were not satisfied with their care.
This was not intended to be a ‘satisfaction study’, since
that portion of the survey was limited to a single global
rating. In general, patient satisfaction is multifactorial
and includes emotional, cultural, psychological and
cognitive elements, and a more detailed psychometric
questionnaire would have been required to measure
satisfaction27. Nevertheless, this low rate may reflect
the active involvement of the anesthesiologists in the
patients’ perioperative care. Many patients commented
positively on their overall impression of their anesthesia
care, with comments about the level of preoperative
attention that they received, the postoperative teaching
and the daily follow-up phone calls.
This is a retrospective patient survey and therefore
not as reliable as a prospective randomized study. It is an
attempt to highlight current practice at this Institution,
with the low incidence of those complications that are
most worrisome to the anesthesia community: Infection,
pulmonary complications and neural injury28. There are
no guidelines on CPNBH. For instance, some prefer
to wear a sterile gown15, some use non-stimulating
catheters1, some prefer ropivacaine2, some coach their
patients on catheter removal while simultaneously on
the phone with them5; there is no consensus on infusion
rate or the need for patient-controlled boluses, or the
length of time catheters can be left in place. At this
M.E.J. ANESTH 20 (2), 2009
218
time, anesthesiologists go by their own Institutional
preferences.
In conclusion, this survey reaffirms that CPNBH
is safe and has few side effects. It reinforces the need
for daily contacts with patients and ties in with the
anesthesiologist’s role as the perioperative physician
who cares about the patient-centered morbidities9
of improved postoperative pain, decreased
nausea, improved quality of sleep, and improved
rehabilitation.
References
1. Borgeat A, Perschak H, Bird P, Hodler J, Gerber C: Patientcontrolled interscalene analgesia with ropivacaine 0.2% versus
patient-controlled intravenous analgesia after major shoulder
surgery. Anesthesiology; 2000, 92:102-8.
2. Ilfeld BM, Morey TE, Wright TW, Chidgey LK, Enneking FK:
Continuous interscalene brachial plexus block for postoperative pain
control at home: A randomized, double-blinded, placebo-controlled
study. Anesth Analg; 2003, 96:1089-95.
3. Capdevila X, Barthelet Y, Biboulet P, Ryckwaert Y, Rubenovitch
J, D’athis F: Effects of perioperative analgesic technique on the
surgical outcome and duration of rehabilitation after major knee
surgery. Anesthesiology; 1999, 91:8-15.
4. Williams BA, Kentor ML, Williams JP, Figallo CM, Sigl JC,
Anders JW, Bear TC, Tullock WC, Bennett CH, Harner CD,
Fu FH: Process analysis in outpatient knee surgery. Effects of
regional and general anesthesia on anesthesia-controlled time.
5. Ilfeld BM, Esener DE, Morey TE, Enneking FK: Ambulatory
perineural infusion: The patient’s perspective. Reg Anesth Pain
Med; 2003, 28:418-23.
6. Borgeat A, Ekatodramis G: Anaesthesia for shoulder surgery. Best
Pract Res Clin Anaesthesiol; 2002, 16:211-25.
7. Borgeat A, Dullenkopf A, Ekatodramis G, Nagy L: Evaluation of
the lateral modified approach for continuous interscalene block after
shoulder surgery. Anesthesiology; 2003, 99:436-42.
8. Richman JM, Liu SS, Courpas G, Wong R, Rowlingson AJ,
McGready J, Cohen S, Wu C: Does continuous peripheral nerve
block provide superior pain control to opioids? A meta-analysis.
Anesth Analg; 2006, 102:248-57.
9. Wu CL, Fleisher LA: Outcomes research in regional anesthesia and
analgesia. Anesth Analg; 2000, 91:1232-42.
10.Tuominen M, Haasio J, Rosenberg P: Continuous interscalene
brachial plexus block: Clinical efficacy, technical problems and
bupivacaine plasma concentrations. Acta Anesthesiol Scand; 1989,
33:84-8.
11.Bader AM, Datta S, Flanagan H, Covino BG: Comparison of
bupivacaine and ropivacaine-induced conduction blockade in the
isolated rabbit vagus nerve. Anesth Analg; 1989, 68: 724-27.
12.Borgeat A, Kalberer F, Jacob H, Ruetsch YA, Gerber C: Patientcontroled interscalene analgesia with ropivacaine 0.2% versus
bupivacaine 0.15% after major open shoulder surgery: the effects on
hand motor function. Anesth Analg; 2001, 92: 218-23.
13.Zink W, Sef C, Bohl JRE, Hacke N, Braun PM, Sinner B, Martin
E, Fink RHA, Graf BM: The acute myotoxic effects of bupivacaine
and ropivacaine after continuous peripheral nerve blockades. Anesth
Analg; 2003, 97:1173-9.
14.Cuvillon P, Ripart J, Lalourcey L, Veyrat E, L’Hermite J, Boisson
C, Thouabtia E, Eledjam JJ: The continuous femoral nerve block
catheter for postoperative analgesia: Bacterial colonization,
infectious rate and adverse effects. Anesth Analg; 2001, 93:1045-9.
15.Capdevila X, Pirat P, Bringuier S, Gaertner E, Singelyn F, Bernard
N, Choquet O, Bouaziz H, Bonnet F: Continuous peripheral nerve
blocks in hospital wards after orthopedic surgery. Anesthesiology;
2005, 103:1033-45.
16.Bergman BD, Hebl JR, Kent J, Horlocker TT: Neurologic
complications of 405 consecutive continuous axillary catheters.
Anesth Analg; 2003, 96:247-52.
17.Adam F, Jaziri S, Chauvin M: Psoas abscess complicating femoral
nerve block catheter. Anesthesiology; 2003, 99:230-1.
18.Nseir S, Pronnier P, Soubrier S, Onimus T, Saulnier F, Mathieu
D, Durocher A: Fatal streptococcal necrotizing fasciitis as a
complication of axillary brachial plexus block. Br J Anaest; 2004,
92:427-9.
19.Ilfeld BM, Enneking FK: Continuous peripheral nerve blocks at
home: A review. Anesth Analg; 2005, 100:1822-33.
20.Ekatodramis G, Borgeat A: Subcutaneous tunneling of the
interscalene catheter. Can J Anaesth; 2000, 47:716-7.
21.Souron V, Reiland Y, Delaunay L: Pleural effusion and chest pain
after continuous interscalene brachial plexus block. Reg Anesth Pain
Med; 2003, 28:535-8.
22.Sardesai AM, Chakrabarti AJ, Denny NM: Lower lobe collapse
during continuous interscalene brachial plexus local anesthesia at
home. Reg Anesth Pain Med; 2004, 29:65-8.
23.Urmey WF, Talts KH, Sharrock NE: One hundred percent incidence
of hemidiaphragmatic paresis associated with interscalene brachial
plexus anesthesia as diagnosed by ultrasonography. Anesth Analg;
1991, 72:498-503.
24.Boezaart AP, deBeer JF, duToit C, van Rooyen K: A new technique
of continuous interscalene nerve block. Can J Anaesth; 1999,
46:275-81.
25.Pere P: The effects of continuous interscalene brachial plexus block
with 0.125% bupivacaine plus fentanyl on diaphragmatic motility
and ventilatory function. Reg Anesth; 1993, 18:93-7.
26.Upton AR, McComas AJ: The double crush in nerve entrapment
syndromes. Lancet; 1973, 2:359-62.
27.Fung D, Cohen MM: Measuring patient satisfaction with anesthesia
care: A review of current methodology. Anesth Analg; 1998,
87:1089-98.
28.Klein SM: Continuous peripheral nerve blocks: Fewer excuses.
Anesthesiology; 2005, 921-3.
EVALUATION OF A BLOOD CONSERVATION
STRATEGY IN THE INTENSIVE CARE UNIT:
A PROSPECTIVE, RANDOMISED STUDY
Saad Mahdy*, Ehtesham I Khan**, M Attia***,
BP O’Brien** And Patrick Seigne***
Abstract
Objective and Methods: Anemia is a common problem in the ICU population. Most
patients are anemic at admission, their hemoglobin concentrations declining further thereafter.
The aim of the present study was to evaluate the effect of a combination strategy, involving
closed arterial blood gas sampling and the use of pediatric vials for phlebotomy (Group A), on
the sampling-induced blood loss and the rate of decline in hemoglobin in adult ICU patients.
Combination (Group A) was compared to the current standard technique of arterial line sampling
and adult vial phlebotomy (Group B) in a prospective, randomised, ethically-approved trial for
the first 72 hours of their ICU stay. Peri-operative, oncology, coagulopathic and uremic patients
were excluded. All other ICU patients with arterial cannulae and predicted to stay beyond 3 days,
were enrolled.
Results: 39 patients entered the study, 20 in Group A, and 19 in Group B. Data collection
was complete for all. There was a statistically significant difference in sampling-induced blood
loss between the groups over the first 72 hours of treatment (mean +/- standard deviation: 15.16
+/- 5.3 ml Group A vs 45.11 +/- 14 ml Group B, p<0.001). There was a smaller decline in mean
hemoglobin level, which was not statistically significant (0.79 +/- 0.6 g/dL vs 1.30 +/- 1.13, p =
0.09).
Conclusions: Overall, this strategy reduced measurable blood losses from phlebotomy. In
larger trials it might also preserve hemoglobin levels.
*
**
FCARCSI, Department of Anaesthesia and Intensive Care Medicine, St Vincent’s University Hospital, Dublin 4.Ireland.
FCPS, FCARCSI, EDICM, DM MD RCSI, Dip in Pain Management RCSI, Department of Anaesthesia and Intensive Care
Medicine, The Mater Hospital, Eccles St, Dublin 7.
*** FCARCSI, Department of Anaesthesia and Intensive Care Medicine, Cork University Hospital, Cork, Ireland (Work
performed in CUH).
Correspondence to: Dr. Ehtesham I. Khan, FCPS, FCARCSI, EDICM DM MD RCSI, Dip in Pain Management RCSI,
Consultant Anaesthetist, 27-Rosehall, Crosslane, Drogheda, CO LOUTH, Rep of Ireland, Mobile: 00353-871347050.
219
M.E.J. ANESTH 20 (2), 2009
220
Introduction
Anemia is a common problem in the critically
ill, with many patients being mildly anemic at
admission to the intensive care unit (ICU)1. Typically,
hemoglobin concentrations decline by about 0.5 gm/
dl/day during the first 3 days of intensive care and
continue declining thereafter, falling more markedly
in those with sepsis and more severe levels of
illness1-4. This patient population is at particular risk
from the adverse consequences of anemia given the
cardiovascular, respiratory, and metabolic compromise
that characterise critical illness. The etiology of this
anemia is multi-factorial: gastrointestinal bleeding,
phlebotomy, coagulation disorders, blood loss
from vascular procedures, renal failure, nutritional
deficiency, bone marrow suppression and impaired
erythropoietin response may be amongst the causes5.
Methods aiming to decrease blood loss in
intensive care are thus potentially worthwhile, even
if only modestly effective. The Venous Arterial Blood
Management Protection6 (or VAMP), Fig. 1 system (a
needleless, closed, blood-sampling system) is designed
to reduce infection, needle-stick injury, and blood
wastage associated with blood sampling. Blood sample
sites incorporate familiar needleless technology for
added safety. Versatile reservoir design can be bracket
mounted on an IV pole next to a pressure transducer
one-handed operation provides convenient blood
withdrawal. Blood volume is held in in-line reservoir
and not set aside, to be reinfused later. Another simple
step that might reduce unnecessary blood loss is the use
of pediatric-sized vials for phlebotomy for laboratory
testing.
The aim of our study was to evaluate the effect
of combining these methods (ie both closed arterial
Fig. 1
Diagram of VAMP, A to Saline drip, B-Pressure transducer, C
to patient, D-blood suction port
Saad Mahdy et. al
blood gas sampling, allowing return of dead-space
blood, along with the use of pediatric blood vials) on
the volume of blood lost through sampling and also
on the progression of anemia, in adult ICU patients.
We compared this to the current practice of arterial
pressure line sampling, where dead-space blood is
discarded, and adult phlebotomy vials are used. We
hypothesised that this combination strategy would
decrease the volume of blood lost through sampling in
critically ill patients and thus reduce the rate of decline
in the patients’ hemoglobin levels and, perhaps, their
need for transfusion.
Approval was obtained from the Ethics and
Research Committee of Cork University Hospital to
conduct a pilot study in order to evaluate the VAMP
system’s efficiency, in a prospective randomised
unblinded controlled clinical study. The study was
carried out in the Hospital’s ICU from January to March
of 2006. Written consent was obtained around the time
of admission from appropriate patients (or their nextof-kin). These included those who were expected to
require more than 3 days of intensive care. Patients with
clinical evidence of bleeding, such as perioperative
or trauma patients, or those with upper and lower
gastrointestinal blood (ie visible blood in the gastric
aspirate or melena) and menstruating female patients
were excluded. Also excluded were oncology patients
and those requiring renal replacement therapies.
Thirty nine patients were randomised into two
groups. (Study group A n = 20) had the VAMP (closed
system) used for blood gas sampling, in which dead
space blood is returned to the patient and the catheter
flushed clear, while group B (the control group n = 19)
had standard sampling systems used. The frequency of
blood gas analysis and phlebotomy complied with the
routine management in ICU (ie once daily, or at the
discretion of the ICU physician and nursing staff, in
turn guided by the clinical condition of the patient).
Pediatric syringes (1 ml) for blood gas analysis
were used in study group A and we used pediatric
vials for hematology and biochemistry analysis, which
required 0.4 and 1.4 mls respectively, as compared to
2.7 and 4.9 mls for adult vials. Standard data collection
for the ICU population was used with a specific
EVALUATION OF A BLOOD CONSERVATION STRATEGY IN THE INTENSIVE CARE UNIT: A PROSPECTIVE,
RANDOMISED STUDY
data sheet being filled in daily for the first 3 days of
intensive care. We recorded as end-points the patients’
hemoglobin concentrations 72 hours after admission,
the total volume of blood taken for phlebotomy and
the number of units of blood transfused over the time
period. Blood volumes removed were measured at
the time of phlebotomy and the volumes recorded
contemporaneously.
Results
The volumes of blood removed for analysis and
the level of decline in hemoglobin levels are shown in
Table 1. The control group had a 65% greater a fall in
hemoglobin levels than the study group, though this
difference was not statistically significant. There is a
statistically significant difference, however, between
the study and control groups in terms of the volume
of blood drained for analysis; about three times more
blood was lost in the control group (15.16 ml vs 45.11
ml). There was no discarded blood in the study group
A as compared to almost 25 mls lost by the average
patient in the control group B. No patients from either
group required blood transfusion during the study.
Discussion
The consequences of anemia in the critically
ill are significant both for patients and for healthcare
institutions. In managing such patients, the immediate
risks of reduced delivery of oxygen to the tissues must
be weighed against the adverse long and short-term
health effects of transfusion and the financial burden
of blood collection and storage.
On the basis of recent research there is a
3
221
current trend in ICU management to accept lower
hemoglobin levels than in previous generations, and
thus to transfuse less blood. Nonetheless, about 40%
of the critically ill population receive transfused blood
during their illness1 such that, in the United States
for example, around 11 million units of red cells are
transfused annually7.
The administration of blood is subject to increased
public scrutiny as, despite best efforts, infectious risks
remain. Such risks, due to the ongoing recognition
of new pathogens such as West Nile virus8, for
example, cannot accurately be quantified at present.
Non-infectious risks, such as circulatory overload,
acute delayed transfusion reactions, microcirculatory
dysfunction, immune modulation, hypocalcemia and
hypothermia, are also associated with transfusion3,7,9,10.
Attempts to make the process safer incur increased
costs: thus, the introduction of measures to improve the
safety and adequacy of the blood supply contributed
to a 51% rise in expenditure by the Canadian Blood
Services1.
Alternatives to transfusion are clearly desirable
then, and are the subject of many diverse strands
of research. These include the administration of
erythropoietin, with or without iron12, and therapy
with blood cell substitutes or synthetic hemoglobin13.
Avoiding the need for transfusion is a more rational and
cost-effective strategy. Many of the tenets of modern
ICU contribute to this strategy-optimising patient
nutrition, avoiding drugs associated with bone marrow
depression, and minimising diagnostic phlebotomy,
for example13.
Diagnostic
phlebotomy
may
contribute
substantially to the anemia encountered in ICU. In
Table 1
Values of blood removed for analysis and level of decline of hemoglobin levels, in Group A and B
Variable
Test (Group A)
Control (Group B)
p-value
N
Mean
SD
N
Mean
SD
Fall in hemoglobin after 3 days
20
0.79
0.61
19
1.30
1.13
0.09
Blood lost on gas sampling
20
5.42
1.14
19
6.56
1.63
0.01
Blood discarded
20
0
0
19
24.83
9.16
<.0001
Blood phlebotomised
20
9.72
4.92
19
13.71
6.89
0.046
Total blood drained
20
15.15
5.32
19
45.1
14.05
<0.0001
M.E.J. ANESTH 20 (2), 2009
222
critically ill surgical patients drawn volumes over
200 mls per day, are described in the literature14,15.
However, the volumes drawn vary widely in different
study populations; values of 40 to 80 mls per day
are more representative of medical patients with
higher values being typical on the day of admission.
Interestingly, a German study found that the total
amount of diagnostic blood loss was a strong predictor
of later transfusion16. Another American study found
that phlebotomy accounted for approximately 50%
of the variation in the amount of red blood cell later
transfused5. Of course, more severely ill patients are
subject to more frequent phlebotomy and thus are at
higher risk of transfusion and its consequences1,17.
The mean frequency of phlebotomy in critical patients
varies widely among published series, ranging from 5
to more than 10 samples per day1,4,17.
Arterial blood gases are the most frequently
ordered laboratory test in ICU and may account for
almost 40% of blood drawn11. The mean volume per
draw depends on the particular blood test, the ICU, and
clinical laboratory practice15,18,19. Published estimate
vary from 1.5 ml to 10 ml for arterial blood gas and
from 4 ml to 10 ml for hematology, coagulation and
chemistry samples. The mean volume per draw in a
recent study covering 145 European ICUs was 10.3
ml1,4,15. Patients with indwelling arterial catheters are
subject to more frequent blood draws and have three
fold increases in phlebotomy volumes compared with
patients without such catheters5,16,17.
Each blood sample taken via an arterial or
central venous catheter tends to result in blood being
discarded, as blood is removed to clear infusate which
might otherwise dilute the specimen. The volume lost
depends on the local medical and nursing practice and
it varies from 2 ml to 10 ml of discarded blood4,20,21.
The discarded volume is recommended to be twice
the volume of the dead space to provide accurate and
reproducible blood gas analysis20. This recommendation
is probably not well known though; the volume lost is
certainly rarely measured.
Our present findings are that through a simple
strategy of closed sampling and the use of pediatric
blood vials, phlebotomy-induced blood loss can be
reduced by about 30 mls per day per patient. This is
Saad Mahdy et. al
likely to be sustained through longer admissions,
perhaps producing a significant clinical benefit and
reducing costs.
The small patient population studied and the
relatively short study period (of 3 days) are amongst
the limitations of the present study. While a longer
study period would probably validate the hypothesis
more clearly, longer lengths of stay are difficult to
predict, so that complete follow up is difficult, and
phlebotomy may become more invasive once arterial
cannulae are removed. Most importantly, other causes
of blood loss will become more frequent with longer
stays, confounding results.
The venous arterial blood management protection
system (VAMP) was introduced in 1989 as a simple
method for clinicians to draw blood samples without
using needles in a closed system6. An added advantage
of this is the elimination of the risk of needle stick
injuries, with obvious benefits. In our evaluation of
the system, no significant problems were encountered
and it succeeded in eliminating the loss of blood as
discarded dead-space volume. Furthermore, no extra
workload was imposed on medical or nursing staff by
the introduction of this method of phlebotomy.
Previous authors have found that pediatric
collection tubes can reduce blood loss by 42%22,23,
but their use is nonetheless not commonplace in adult
medical practice. Our findings, in conjunction with
these, show that it is feasible to use smaller vials in
the adult ICU population. In conclusion, we suggest
that the combined approach evaluated can make a
modest but potentially clinically significant impact on
the volumes of blood drawn from critically ill patients
without adverse effect and recommend it for further
evaluation or use.
Acknowledgement
We thank the nursing staff of Intensive Care Unit
of Cork University Hospital for their help in study and
the intensive care registrars working in the ICU for
their help with the collection of data.
This study was sponsored by Edward Lifesciences,
European Headquarters, S.A.Ch. Du Glapin 6 1162,
Saint-Prex Switzerland.
EVALUATION OF A BLOOD CONSERVATION STRATEGY IN THE INTENSIVE CARE UNIT: A PROSPECTIVE,
RANDOMISED STUDY
223
References
1. Vincent JL, Baron J-F, Reinhart K, et al: Anemia and blood
transfusion in critically ill patients. JAMA; 2002, 288:1499-1507.
2. Levy M: The North American CRIT Trial. Society of Critical Care
Medicine, San Diego, April 7, 2002.
3. Hebert PC, Wells G, Blajchman M ,et al: A multicenter,
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M.E.J. ANESTH 20 (2), 2009
INTRAVENOUS DEXMEDETOMIDINE PROLONGS
BUPIVACAINE SPINAL ANALGESIA
Mahmoud M Al-Mustafa*, Izdiad Z Badran**,
Hamdi M Abu-Ali***,Bassam A Al-Barazangi*,
Isalm M Massad* and Subhi M. Al-Ghanem****
Abstract
Background: The prolongation of spinal anesthesia by using clonidine through the oral,
intravenous and spinal route has been known. The new α2 agonist, dexmedetomidine has been
proved to prolong the spinal anesthesia through the intrathecal route. We hypothesized that
dexmedetomidine when administered intravenously following spinal block, also prolongs spinal
analgesia.
Methods: 48 patients were randomly allocated into two equal groups following receiving
spinal isobaric bupivacaine 12.5 mg. Patients in group D received intravenously a loading dose of
1 μg/kg dexmedetomidine over 10 min and a maintenance dose of 0.5 μg/kg/hr. Patients in group
C (the control group) received normal saline. The regression times to reach S1 sensory level and
Bromage 0 motor scale, hemodynamic changes and the level of sedation were recorded.
Results: The duration of sensory block was longer in intravenous dexmedetomidine group
compared with control group (261.5 ± 34.8 min versus 165.2 ± 31.5 min, P <0.05). The duration
of motor block was longer in dexmedetomidine group than control group (199 ± 42.8 min versus
138.4 ± 31.3 min, P <0.05).
Conclusion: Intravenous dexmedetomidine administration prolonged the sensory and motor
blocks of bupivacaine spinal analgesia with good sedation effect and hemodynamic stability.
Keywords: Anesthesia, spinal; dexmedetomidine; bupivacaine; intravenous.
From Faculty of Medicine, Univ. of Jordan, Amman, Jordan. Dept. of Anesthesia & IC.
*
MD.
**. MD, Prof.
**** MD, Head of Dept.
Department of General Surgery.
*** MD.
Correspondence to Mahmoud Al-Mustafa, MD, Department of Anesthesia and Intensive Care, Jordan University
Hospital, P.O. Box: 13046, Amman, Jordan 11942. Tel: +962 (6) 5353666 Ext. 2420, Fax: +962(6) 5353388,
225
M.E.J. ANESTH 20 (2), 2009
226
Introduction
Spinal analgesia is a well-known technique used
in urological procedures; transurethral resection of
prostate (TURP), transurethral resection of bladder
tumors (TURT) or Tension-free Vaginal Tape (TVT).
The operative blood loss in TURP and TURT in spinal
anesthesia is less in comparison to inhalational general
anesthesia1. An intra-operative cough test helps to
correctly position the tape in the TVT surgery during
spinal anesthesia.
Different agents, like epinephrine, phenylephrine,
adenosine, magnesium sulfate and clonidine, have been
used as adjuncts to local anesthesia for prolonging
the duration of spinal analgesia via the intrathecal
route. Small doses of dexmedetomidine (3 µg) used
in combination with bupivacaine in humans in spinal
anesthesia produces a shorter onset of motor block and
a prolongation in the duration of motor and sensory
block with preserved hemodynamic stability and lack
of sedation2. Clonidine an α2-agonists, has been used
widely in the intrathecal route3,4,5,6. It has been used
intravenously within one hour after the spinal block and
found that it prolonged bupivacaine spinal anesthesia
for approximately one hour without adverse effect7.
Dexmedetomidine, also an α2-agonist, has
been used for pre-medication and as an adjunct to
general anesthesia8,9,10. Intravenous Dexmedetomidine
decreases the inhalational anesthesia and opioid
requirements
during
general
anesthesia11.We
hypothesize that intravenous dexmedetomidine, might
prolong the duration of spinal analgesia similar to
clonidine.
Mahmoud M Al-Mustafa et. al
inhibitors, having dysrhythmia by ECG, body weight
more than 120 Kg, or height less than 150 cm, were
excluded from the study. All patients were prehydrated with 300 ml of Ringer’s Lactate solution via
an 18-gauge IV cannula in the dorsum of the hand.
Standard monitoring was used, including non-invasive
arterial blood pressure (BP), ECG, heart rate (HR) and
pulse oximetry. Patient motor power and sensation
to cold using alcohol solution up to T10 dermatome
were examined in both lower extremities. All patients
received 4 L/min of O2 by simple face mask.
With the patient in the sitting position, spinal
analgesia was performed at the level of L3-L4 through
a midline approach using a 25-gauge Quincke spinal
needle (B/Braun Medical, Messenger, Germany) with
the hole pointing upwards. If the spinal block failed
at the level of L3-L4, we changed the level to L2L3. In case of failure at both levels; the procedure
was abandoned, general anesthesia administered and
those patients were excluded from the study. The
spinal injection rate of bupivacaine 0.5% was 1ml/3-4
seconds in all patients. Using a computer-generated
random list, patients were divided into two groups of
24 each. Control group (group C), received normal
saline intravenously and the dexmedetomidine group
(group D), received intravenous dexmedetomidine.
Isobaric 0.5 % bupivacaine, 12.5 mg (2.5
ml), was injected intrathecally in all patients. 50 cc
syringe was prepared with either normal saline or
dexmedetomidine. (Precedex 100 µg/ml; Hospira,
Inc.) diluted with normal saline in a concentration of
4μg/ml. Immediately after spinal analgesia patients
were laid back to supine position. Patients allocated
to group D received intravenously through the
intravenous infusion pump a loading dose of 1 μg/kg/
hr dexmedetomidine over 10 min and a maintenance
dose of 0.5 μg/kg/hr till the end of surgery. Patients in
group C received also in 10 min, the same calculated
volume normal saline of loading and maintenance dose
as in group D.
Following approval of the Ethical Committee
and obtaining written informed consent from patients,
forty eight patients, ASA I-III, scheduled for TURP,
TURT or TVT were enrolled in the study. Patients
using α2-adrenergic receptors antagonists, calcium
channel blockers, angiotensin converting enzyme
The intravenous formula was prepared by an
anesthetist doctor and was passed on to the doctor
who performed the spinal analgesia who was blinded
as to which group the patient was allocated. The
anesthesiologist to perform the block recorded the
baseline value of vital signs (blood pressure, heart rate
The aim of this study, therefore was to evaluate
the prolongation of spinal analgesia by the intravenous
dexmedetomidine administration after the spinal block,
and to assess the hemodynamic changes and the level
of sedation.
INTRAVENOUS DEXMEDETOMIDINE PROLONGS BUPIVACAINE SPINAL ANALGESIA
and peripheral oxygen saturation). After performing
the spinal block, the vital signs were recorded at 2, 5,
and every 5 minutes in the operation room and every
15 minutes in the Post Anesthesia Care Unit (PACU)
until the patient was discharged to his ward, after
having achieved complete reversal of sensory and
motor block.
In the PACU, the sensory level and Bromage scale
was recorded every 15 minutes until the patient was
discharged from the PACU. The times of regression to
the S1 dermatome and reach Bromage scale 3 in PACU
were recorded. The sensory level was assessed by cold
sensation using alcohol swab along the mid-clavicular
line bilaterally. The motor level was assessed according
to the modified Bromage scale:
Bromage 0, the patient is able to move the hip, knee
and ankle;
Bromage 1, the patient is unable to move the hip, but is
able to move the knee and ankle;
Bromage 2, the patient is unable to move the hip and
knee, but is able to move the ankle;
Bromage 3, the patient is unable to move the hip,
knee and ankle. All durations were calculated
considering the time of spinal injection as time
zero. When sensory levels of anesthesia were not
equal bilaterally, the higher level was used for
the statistical analysis. Patients were discharged
from the PACU after sensory regression to the S1
segment and Bromage scale 0.
For the purpose of this study, hypotension was
defined as a systolic blood pressure of less than 90
mmHg and if maintained, was treated with a bolus
administration of 300 ml of lactated Ringer’s solution
over 10 min and 6 mg of intravenous ephedrine.
Bradycardia was defined as HR <50 beats/min, and
if maintained was treated with 0.5 mg of intravenous
atropine.
The level of sedation was evaluated intraoperatively and post-operatively every 15 min using
Ramsey Level of Sedation Scale:
1.
2.
3.
4.
Patient anxious, agitated, or restless;
Patient cooperative, oriented, and tranquil alert;
Patient responds to commands;
Asleep, but with brisk response to light glabellar
tap or loud auditory stimulus;
227
5. Asleep, sluggish response to light glabellar tap or
loud auditory stimulus.
6. Asleep, no response.
All sedation scores were recorded considering
the time of start infusion as time zero.
Two weeks following discharge, all patients were
evaluated in the outpatient clinic. The doctor in charge
assessed any new onset of neurological impairment
related to spinal anesthesia such as back, buttock or
leg pain, headache or any new neurological deficit.
Statistical Methods
Statistical analysis was done using statgraphics
Centurion XV (Statpoint, Herdon, Virginia –
USA). Data was expressed as either mean and
standard deviation or numbers and percentages. The
demographic data of patients were studied for each
of the three groups. The means of the continuous
variables (Age, BMI, and duration of surgery) were
compared between the three groups using analysis of
variance ANOVA, while the demographic data for the
categorical variables (sex, ASA class) were compared
using chi-square test. Adverse effects and treatment
factors (blood transfusion, nausea/vomiting, occurrence
of hypotension, bradycardia, use of ephedrine, use
of additive analgesia, the use of atropine) were also
compared using the chi-square test. The P value of
<0.05 was considered significant.
Results
Forty eight patients (Cn = 24) (Dn = 24) were
enrolled, completed the study protocol and were
included in the data analysis. The demographic data
did not differ between the two study groups (Table 1).
Table 1
Demographic data. Values are the means ± standard deviations
or numbers
C (n=24)
D (n=24)
P value
Age
64.2 ± 9.7
64.7 + 12.5
0.87
Sex (Male/Female)
19/5
19/5
P=NS
BMI
28.1 ± 4.6
26.6 ± 3.7
0.23
ASA I/II/III
19/3/2
18/4/2
0.76
Surgery –
TURP/TVT
TURT/ 10/9/5
10/9/5
P = NS
M.E.J. ANESTH 20 (2), 2009
228
Time to regression to S1 dermatome and
Bromage scale 0, was significantly prolonged in group
D in comparison with group C. The regression time
to S1 in group C was 165.2 ± 31.5 min and group D
261.5 ± 34.8 min, the P value <0.0001. The regression
time to reach the Bromage 0 scale was 138.4 ± 31.3
min in group C and 199.9 ± 42.8 min in group D, the P
value <0.0001 (Table 2).
first hour in the operation room and comparable in the
PACU (Fig. 2).
Table 2
Block regression times in minutes. Values are the means ±
standard deviations
The oxygen saturation was higher than 95% in all
patient in the two groups either in the intraoperative or
in the PACU time.
C (n=24)
D (n=24) P value
Motor block regression
to Bromage 0
138.4 ± 31.3 199.9 ±
42.8
<0.0001
Sensory regression to S1
segment
165.2 ± 31.5 261.5 ±
34.8
<0.0001
The duration of surgery, need to give ephedrine
or atropine, bradycardia, hypotension, need to additive
analgesia, blood transfusion, nausea or vomiting in
the intraoperative or PACU time, were comparable in
the two groups (P >0.05). The total amount of fluids
administered following spinal anesthesia was higher
in group C as compared to D group (910.8 ± 280.1
versus. 864.5 ± 172.8; p = 0.025) (Table 3).
Table 3
Surgical characteristics, adverse events and treatment. Values
are the means ± standard deviations or numbers
C (n=24)
Total IV infusion
D (n=24)
P value
910.8 ± 280.1 864.5 + 172.8 0.025
Duration of Surgery 42.8 ± 7.5
45.1 ± 8.3
0.32
Blood transfusion
1/23
1/23
0.46
Additive analgesia
1/23
0/24
0.58
Nausea&Vomiting
1/23
0/24
0.32
Bradycardia
2/22
4/20
0.46
Hypotension
4/20
0/24
0.15
Atropine
0/24
2/22
0.65
Ephedrine
1/23
0/24
0.60
The mean values of mean arterial pressure in the
first hour after performing the spinal anesthesia and
the first hour in the PACU (Recovery room) were
comparable between the tow groups (Fig. 1).
The mean value of heart rate was significantly
decreased in group D in comparison to group C in the
Ramsey sedation scale was 2 in all patients
in group C, and ranged from 2-5 in group D, the
maximum score was 5 in 3 patients, 4 in 19 patients,
and 3 in one patients, and the maximum mean score
of sedation (3.96 ± 0.55) was achieved 30 min after
starting dexmedetomidine infusion (Fig. 3).
Two weeks following discharge from the
outpatient clinic, the follow up did not show any
neurological impairment related to spinal analgesia
such as back, buttock or leg pain, headache or any new
neurological deficit.
Discussion
Different drugs have been used as adjuvant to
local anesthesia in order to prolong the duration of
spinal analgesia. Clonidine an α2 agonist, has been
used widely in the intrathecal, oral and intravenous
routes to prolong the duration of spinal analgesia. It is
known to have prolonging effect on sensory and motor
blocks when used as an oral premedication within 2 h
before bupivacaine spinal anesthesia12. The intravenous
administration of clonidine within 1 h after the spinal
block prolonged bupivacaine spinal analgesia for
approximately 1 h without adverse effect13.
Dexmedetomidine, also an α2 agonist, is
pharmacologically related to clonidine, has 8 times
more affinity for α2 receptors than does clonidine.
It produces sedation and anxiolysis by binding to α2
receptors in the locus ceruleus, which diminishes the
release of norepinephrine and inhibits sympathetic
activity, thus decreasing heart rate and blood pressure.
It produce analgesia by binding to adrenoreceptors in
the spinal cord14. It has been used as adjuvant to local
anesthesia in the intrathecal route and has significant
effect on onset and duration of spinal anesthesia2.
Dexmedetomidine has an onset of action of 30 min
when the maintenance dose is used intravenously. Use
of standard loading dose is used (1 µg/Kg/hr infused
over 10 minutes)14, decreases the onset of action of
dexmedetomidine. Side effects of dexmedetomidine,
229
Fig. 1
Comparison of Mean arterial pressure (MAP) levels among group C and D in first hour
after spinal analgesia and first hour in Recovery room (R). Values are expressed as mean ± SD
120
mmHg
115
110
105
100
D
95
90
C
85
80
60
45
R
Bp
30
R
Bp
15
R
Bp
0
Bp
Bp
R
60
R
45
BP
30
BP
25
BP
20
BP
15
BP
10
BP
5
BP
BP
Bp
pr
e
BP
2
75
70
Time
Fig. 2
Comparison of Heart Rate (HR) levels among group C and D in first hour after spinal analgesia
and first hour in Recovery room (R). Values are expressed as mean ± SD
95
90
beat/min
85
80
75
D
70
C
65
60
55
60
HR
45
R
HR
30
R
HR
15
R
R
HR
0
HR
R
60
45
HR
HR
30
HR
25
20
HR
15
HR
10
HR
HR
5
2
HR
HR
Hr
pr
e
50
Time
Fig. 3
Comparison of Ramsay sedation score among group C and D. Values are expressed as mean ± SD
Ramsay Sedation Score
6
5
4
D
3
C
2
1
0
sed 0
sed15
sed30 sed 45 sed60
sed75 sed 90 sed105 sed120 sed135
Time
M.E.J. ANESTH 20 (2), 2009
230
such as hypotension and bradycardia, are dose
dependent, Infusion of loading dose over 10 min and
then infusing the maintenance dose decreases the
incidence of those side effects.
Jorm et al13 found that dexmedetomidine has
an inhibitory effect on the locus ceruleus (A6 group)
located at the brain stem. This supraspinal action could
explain the prolongation of spinal anesthesia after
intravenous administration of dexmedetomidine. The
noradrenergic innervation of the spinal cord arises from
the noradrenergic nuclei in the brain stem including the
locus ceruleus, the A5, and the A7 noradrenergic nuclei.
Neurons in the locus ceruleus are connected to the
noradrenergic nuclei in the brain stem. Axon terminals
of the noradrenergic nuclei reach lamina VII and VIII
of the ventral horns of the spinal cord. The activity of
the noradrenergic neurons is decreased by agonists
acting at α2-adrenergic receptors on the locus ceruleus
cell bodies. Therefore, inhibition of the locus ceruleus
results in disinhibition of the noradrenergic nuclei and
exerted descending inhibitory effect on nociception
in the spinal cord15. In group D, the prolongation of
motor block is less in comparison to its sensory
block (199.9 ± 42.8 min versus 261.5 ± 34.8 min).
The mechanism of motor block is unclear, the
analgesic effects of α2-adrenergic agonists could be
mediated through supraspinal, spinal, and peripheral
actions16. There is some evidence that clonidine
results in direct inhibition of impulse conduction in
the large, myelinated Aα fibers and the 50% effective
concentration (EC50%) measured approximately
4-folds of that in small, unmyelinated C fibers17. This
could explain the less prolonged motor block compared
with sensory block, as conduction of motor nerve fibers
was less inhibited than sensory nerve fibers at the same
concentration of clonidine. The same process might be
applied to dexmedetomidine, and would explain the
more sensory than motor block prolongation.
Dexmedetomidine is known to have sedation
effect18; providing better conditions for the surgeon
and the patient, provided that hemodynamic stability
is preserved. In our patients, Ramsay sedation scores
ranged from 2-5, the maximum score in group D was 3.96
± 0.55. The heart rate decreased significantly after the
start of intravenous infusion loading dose and extended
in the PACU (Fig. 2). This decrease in the heart rate was
more clear and significant in group D in comparison
with group C. The lower HR observed in group D could
be explained by the decreased sympathetic outflow and
circulating levels of catecholamines that are caused by
dexmedetomidine19,20.Other studies support the finding
that the bradycardia effect of dexmedetomidine is long
lasting when used as a premedication drug21,22. Six
patients developed bradycardia (HR <50 beat/min),
only two patients in group D needed to have atropine to
reverse the bradycardia, and statistically and clinically
this was not significant.
Previous studies have shown that the hypotensive
effect of dexmedetomidine persists in the intraoperative
as well as in the postoperative period22,23. In our
patients the mean arterial pressure was also decreased
in the D group as well as the C group (Fig. 1) and
clinically was not significant. There was no further
decrease in the blood pressure after adding intravenous
dexmedetomidine to spinal anesthesia. Only one patient
in group C received ephedrine because of decrease the
systolic blood pressure lower than 90 mmHg, which
statistically was not significant. The total intravenous
fluid administered during surgery was less in group
D in comparison with group C (864.5 ± 172.8 versus
910.8 ± 280.1, p = 0.025).
In conclusion, supplementation of spinal
anesthesia with intravenous dexmedetomidine
produces significantly longer sensory and motor
block than spinal analgesia alone. Adverse side effects
were avoided by the slow infusion of loading and the
maintenance dose of dexmedetomidine. All patients
reached good sedation levels that enabled their
cooperation and better operating conditions for the
surgeon without significant respiratory depression.
231
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20.Scheinin H, Karhuvaara S, Olkkola KT, et al: Pharmacodynamics
and pharmacokinetics of intramuscular dexmedetomidine. Clin
Pharmacol Ther; 1992, 52:537-46.
21.Arain SR, Ebert TJ: The efficacy, side effects, and recovery
characteristics of dexmedetomidine versus propofol when used for
intraoperative sedation. Anesth Analg; 2002, 95:461–6.
22.Aantaa R, Jaakola Ml, Kallio A, Kanto J, Scheinin M, Vuorinen
J: A comparison of Dexmedetomidine, an alpha2-adrenoreceptor
agonist, and midazolam as i.m premedication for minor
gynaecological surgery. Br J Anaesth; 1991, 67:402-9.
23.Virkkilä M, Ali-Melkkilä T, Kanto J, Turunen J, Scheinin
H. Dexmedetomidine as intramuscular premedication for daycase cataract surgery. A comparative study of dexmedetomidine,
midazolam and placebo. Anaesthesia; 1994, 49(10):853-8.
23.Jaakola ML: Dexmedetomidine premedication before intravenous
regional anesthesia in minor outpatient hand surgery. J Clin Anesth;
1994, 6(3):204-11.
M.E.J. ANESTH 20 (2), 2009
ATTENUATION OF HEMODYNAMIC RESPONSES
FOLLOWING LARYNGOSCOPY
AND TRACHEAL INTUBATION
- Comparative assessment of Clonidine and Gabapentin Premedication
Seyed Mojtaba. Marashi, Mohammad Hossein. Ghafari*
and A lireza S aliminia
Abstract
Objective: The present study was conducted to compare the effect of clonidine and gabapentin
premedication in modifying the hyperdynamic response following laryngoscopy and tracheal
intubation.
Methods and Materials: Seventy-five ASA I-II patients of both sexes (37 males (49.3%), 38
females (50.7%)) 18 to 45 years (mean 32.8 ± 8.65yr.) were randomly allocated into three equal
groups (25 each). Group-1 received 0.2 mg clonidine, Group-2 received placebo and Group-3
received 900 mg gabapentin, 120 minute before operation. Heart rate, systolic, diastolic and mean
arterial blood pressure were measured before induction of anesthesia, before laryngoscopy, and 1,
3, 5, 10 min after intubation.
Results: Analysis revealed that the heart rate, systolic, diastolic and mean arterial blood
pressure significantly differed between groups (p<0.001, p = 0.003, p<0.001, p<0.001, respectively).
The highest rates of heart rate, systolic, diastolic and mean arterial blood pressure were in the
placebo group and in one minute after laryngoscopy, and the lowest rate were in the gabapentin
group at the time of 1, 3, 5 and 10 after laryngoscopy, except that the lowest rate of heart rate in 10
min after laryngoscopy was in clonidine group.
Conclusion: The data propose that both clonidine and gabapentin have effective role in
blunting hyperdynamic responses after laryngoscopy, more so with gabapentin.
From Department of Anesthesiology and Critical Care, Shariati Hospital, Medical Sciences/University of Tehran, Iran.
*
Coressponding author: Mohammad Hossein Ghafari, MD, Anesthesiologist, Shariati Hospital, North Kargar Street, TehranIran Postal code: 1411713135. Tel: +98 9123754496, Fax: +98 2188026017. E-mail: [email protected]
233
M.E.J. ANESTH 20 (2), 2009
234
Introduction
Manipulation of the respiratory tract such as in
laryngoscopy and tracheal intubation are associated
with hemodynamic and cardiovascular responses
consisting of increased circulating catecholamines,
heart rate, blood pressure, myocardial oxygen
demand, tachycardia and dysrhythmias1,2. In the recent
decade, several studies have focused on clonidine and
newly on gabapentin premedication to attenuate the
hemodynamic responses following laryngoscopy and
intubation. However, there was no comparative study.
Clonidine is a α2- adrenoceptor agonist with
sedative and analgesic effects, also has the beneficial
effect of blunting hyperdynamic responses due to
laryngoscopy and tracheal intubation2-8. In addition
gabapentin, a structural analogue of the γ-aminobutyric
acid (GABA) is known as an anticonvulsant drug
that has various analgesic effects. Recently, its role
in attenuating of hemodynamic responses following
laryngoscopy and intubation has been noticed1,9,10.
The present study was performed to compare the
effect of clonidine and gabapentin on modifying the
hemoynamic responses following laryngoscopy and
tracheal intubation.
Data source
Written informed consent from all patients was
obtained and the study was approved by the Hospital’s
Ethics Committee.
This is a double-blind, placebo-controlled
randomized study. Seventy-five ASA I-II patients
aged 18-45 years (mean 32.8 ± 8.65 years) of both
sexes comprised of 37 male (49.3%) and 38 female
(50.7%) were enrolled into the study. Patients were
scheduled for elective orthopedic and general surgical
procedures under general anesthesia. Exclusion
criteria consisted of urgent surgical procedures,
body mass index (BMI) more than 30, hiatal hernia,
gastroesophageal reflux, history of allergy to clonidine
or gabapentin, history of cerebrovascular, neurologic,
cardiovascular, respiratory, hepatic and renal disease,
hypertension and pheochromocytoma, patients with
history of drug or alcohol abused, patients who were
Seyed Mojtaba Marashi et. al
administered daily β-blocker, antidepressant, antianxiety, anticonvulsant or antipsychotic drugs, any
history of immunity response to muscle relaxant drugs
or history of neuromuscular disease that would made
muscle relaxants contraindicated, difficult intubation
(Mallampati class III-IV or laryngoscopic grade IIIIV), prolonged laryngoscopic time (more than 30
second).
Randomization and drugs
Patients were randomly divided to three equal
groups (25 each) according to a computerized random
table. All patients received premedication drugs 120
minute before admission to the operating room.
Group-1, patients received 0.2 mg clonidine (0.2
mg × 1 capsule + 2 placebo capsules).
Group-2, patients received placebo (3 capsules).
Group-3, patients received 900 mg gabapentin
(300 mg × 3 capsules).
Technique of anesthesia
Following insertion of intravenous catheter, all
patients were infused with 5 ml/kg normal saline.
Routine monitoring comprised, ECG, pulse oximetry,
and non-invasive blood pressure.
2.5 µg/kg Fentanyl and 0.03 mg/kg midazolam
intravenous as premedication was administered before
induction of anesthesia. Patients were preoxygenated
for 3 minutes with oxygen 100% and anesthesia was
induced with 5 mg/kg thiopental sodium and 0.5 mg/
kg atracurium. Three minutes later, laryngoscopy
using Macintosh blade size 3 and intubation using
intratracheal tube (size 7.5-8) were performed by
an anesthetist or by a two-year trained resident in
anesthesiology. Heart rate, systolic, diastolic and mean
arterial blood pressure were recorded before induction
of anesthesia, before laryngoscopy, and 1, 3,5,10 min
after intubation.
Statistical analysis
Data was represented as mean ± standard
deviation for interval and count (relative frequency)
for categorical variables. Baseline data were compared
among study groups by one-way analysis of variance
(ANOVA) for interval and Chi-square (and Fisher’s
ATTENUATION OF HEMODYNAMIC RESPONSES FOLLOWING LARYNGOSCOPY AND TRACHEAL INTUBATION
exact) test for categorical data. Repeated measure
ANOVA model was used to compare variations in
different time intervals and among study groups. A
p-value of less than 0.05 was considered significant.
Statistical analysis was performed using SPSS 11.5 for
Windows (SPSS Inc., Chicago, Illinois).
Results
Table-1 shows distribution of sex, mean of age
and weight in each group with no significant differences
between the three groups (respectively; p = 0.5, p = 0.
2, p = 0.4).
HR: The placebo group recorded highest mean
HR 101.16 ± 16.48 (beat/min) in one minute after
laryngoscopy. The clonidine group recoded the lowest
HR 69.12 (beat/min) in 10 minutes after laryngoscopy.
Heart rate differed with regard to groups (p<0.0001)
also with regard to time between groups (p<0.0001).
HR profile is shown in (Fig.1).
SAP: The highest mean SAP 148.88 ± 14.12
(mmHg) belonged to placebo group in one minute after
laryngoscopy and the lowest one was 99.76 ± 14.69
(mmHg) belonged to gabapentin group in 10 minutes
after laryngoscopy. SAP differed with regard to group
(p = 0.003) also with regard to time between groups
(p<0.0001). SAP profile is shown in (Fig. 2).
DAP: The highest mean DAP was 98.60 ± 11.49
(mmHg) belonged to gabapentine group in 10 minutes
after laryngoscopy. SAP differed with regard to group
(p<0.0001) also with regard to time between groups
(p<0.0001). DAP profile is shown in (Fig. 3).
235
MAP: The highest mean MAP was 115.36 ± 11.40
(mmHg) belonged to gabapentin group in 10 minutes
after laryngoscopy. MAP differed with regard to group
(p<0.0001) also with regard to time between groups
(p<0.0001). MAP profile is shown in (Fig. 4).
Discussion
Gabapentin is a known anticonvulsant drug with
wide spread effects on pain9. Its efficacy on attenuating
hemodynamic responses following laryngoscopy was
revealed by Fassoulaki and colleagues in 20061. They
showed SAP and DAP significantly were lower in the
gabapentin group than in the control group (p<0.05)
immediately also in 1, 3, 5 and 10 minute after
laryngoscopy but HR did not differ between two groups
at any of the times. Kayan and colleagues in 200811
demonstrated attenuation of gabapentin on MAP in the
first 10 minutes following endotracheal intubation.
The attenuating effect of clonidine has previously
been documented by many studies2,3,5-8. Our data also
confirmed HR, SAP, DAP and MAP significantly differ
with regard to groups and to times (all the p-values
were less than 0.05). Between the groups, the highest
rate of HR, SAP, DAP and MAP were in the placebo
group especially in one minute after laryngoscopy.
It follows that both clonidine and gabapentin have
effective roles in blunting hemodynamic responses
following laryngoscopy.
The type of surgery and the quantity of surgical
stimulation in the first 10 min of anesthesia induction
was not exactly adjusted in all patients. These can be
Table1
Patients characteristics in each group
characteristics
Clonidine group
(Group-1)
Placebo group
(Group-2)
Gabapentin group
(Group-3)
P-value
Gender
Male
Female
13(52%)
12(48%)
14(56%)
11(44%)
10(40%)
15(60%)
Age (years)
32.88 ± 8.57
30.72 ± 7.59
34.96 ± 9.51
0.2
Weight (kg)
67.88 ± 11.25
67.12 ± 14.65
71.32 ± 10.68
0.4
0.5
Values are presented as n (%) or mean ± SD.
M.E.J. ANESTH 20 (2), 2009
236
Seyed Mojtaba Marashi et. al
Results of our study suggest that both clonidine
and gabapentine have effective roles in blunting the
hyperdynamic responses following laryngoscopy,
more so with gabapentine. It also suggests that there
are significant differences between gabapentin,
clonidine and placebao in modifying the hemodynamic
responses in the first 10 min. after laryngoscopy. It is
recommended that further studies be done to compare
the effects of gabapentine and its dosage, with the
newer a2- adrenoreceptor, like dexmedetomidine, on
modifying the hemodynamic variables following
laryngoscopy.
Fig. 1
Plot of estimated means of HR according to groups
and time
Fig. 2
Plot of estimated means of SAP according to groups
and times
considered as our study limitation; however, an effort
was made to start surgery 10 min after anesthesia
induction.
Conclusions
Mean HR
Mean SAP
110
160
150
100
140
HR
SBP
90
130
80
120
group
group
110
Control
70
Control
Clonidine
100
Clonidine
60
Gabapentin
90
Before
induction
1 min
Gabapentin
5 min
3 min
Before
induction
10 min
Befor
laryngoscopy
1 min
5 min
3
min
Before
laryngoscopy
10 min
TIME
TIME
Fig. 4
Plot of estimated means of MAP according to groups
and times
Fig. 3
Plot of estimated means of DAP according to groups
and times
Mean DAP
Mean MAP
DAP
110
MAP
120
110
100
100
90
90
group
80
group
control
80
control
70
Clonidine
Clonidine
60
Gabapentin
Before
I
induction Before min
laryngoscopy
5 min
3 min
10 min
70
Gabapentinn
Before
induction
1 min
3 min
Before
Laryngoscopy
TIME
TIME
5 min
10 min
ATTENUATION OF HEMODYNAMIC RESPONSES FOLLOWING LARYNGOSCOPY AND TRACHEAL INTUBATION
237
References
1. Fassoulaki A, Melemeni A, Paraskeva A, P etropoulos G:
Gabapentin attenuates the pressor response to direct laryngoscopy
and tracheal intubation. Br J Anaesth; 2006, 96:769-73.
2. Matot I, Sichel J, Yofe V, Gozal Y: The Effect of clonidine
premedication on hemodynamic responses to microlaryngoscopy
and rigid bronchoscopy. Anesth Analg; 2000, 91:828-33.
3. Barat YK, Indu B, Puri GD: Attenuation of pulse rate and blood
pressure response to laryngoscopy and tracheal intubation by
clonidine. Int J Clin Pharmacol Ther Toxicol; 1998, 26: 360-3.
4. Nishikawa T, Taguchi M, Kimura T, Taguchi N, Sato Y, Dai M:
Effects of clonidine premedication upon hemodynamic changes
associated with laryngoscopy and tracheal intubation. Masui; 1991,
40:1083-8.
5. Watanabe T, Inagaki Y, Ishibe Y: Clonidine premedication effects on
inhaled induction with sevoflurane in adults: a prospective, doubleblind, randomized study. Acta Anaesthesiol Scand; cta Anaesthesiol
Scand; 2006, 50:180-7.
6. alunardo MP, Zollinger A, Szelloe P, Spahn DR, Seifert B, Pasch
T: Cardiovascular stress protection following anesthesia induction.
Comparison of clonidine and esmolol. Anaesthesist; 2001, 50:21-5.
7. Yokota S, Komatsu T, Yano K, Taki K, Shimada Y: Effect of oral
clonidine premedication on hemodynamic response during sedated
nasal fiberoptic intubation Nagoya J Med Sci; 1998, 61:47-52.
8. Laurito CE, Baughman VL, Becker GL, Cunningham FE, Pygon
BH, Citron GM: Oral clonidine blunts the hemodynamic responses
to brief but not prolonged laryngoscopy. J Clin Anesth; 1993, 5: 5457.
9. Kong VK, Irwin MG: Gabapentin: a multimodal perioperative drug?
Br J Anaesth; 2007, 99:775-86.
10.Memis D, Turan A, Karamanlioglu B, Seker S, Ture M: Gabapentin
reduces cardiovascular responses to laryngoscopy and tracheal
intubation. Eur J Anaesthesiol; 2006, 23:686-90.
11.Kayan FN, Yavascaoglu B, Baykara M, Altun GT, Gulhan N,
Ata F: Effect of oral gabapentin on the intraocular pressure and
haemodynamic responses induced by tracheal intubation. Acta
Anesthesiol Scan; 2008, 52: 1076-80.
M.E.J. ANESTH 20 (2), 2009
PEDIATRIC CANCER PAIN MANAGEMENT
AT A REGIONAL CANCER CENTER:
IMPLEMENTATION OF WHO ANALGESIC LADDER
Seema Mishra*, Sushma Bhatnagar**, Manisha Singh***,
Deepak Gupta****, Roopesh Jain***, Himanshu Chauhan***,
and G aurav N irwani G oyal ***
Abstract
Purpose: To collect data on the prevalence of various types of cancer pain in a sample of
children with cancer, and to implement the WHO Analgesic Ladder in the management of pain in
pediatric cancer.
Methods: Eighty four pediatric patients suffering of cancer pain were studied during the
period 2001-2006. Patients were requested to rate their global intensity of pain on 0-100 mm
visual analogue scale (VAS 0 = no pain 100 = maximum pain). Pain management was performed
in accordance with the WHO Analgesic Ladder for cancer pain. Patients were followed up weekly
for three weeks.
Results: Of the 84 pediatric children with cancer, pain was nociceptive in 26 (31%),
neuropathic in 12 (14.3%) and mixed in 46 (54.8%). Almost 7 (8.3%) of patients were on WHO
step 3 at baseline. Thereafter the WHO step 3 increased; first week visit 36 (43%) patients; second
week visit 58(69%), and third week 69 (82.1%). At baseline, 40 (47.6%) patients took NSAID
only, 2 (2.4%) patients took adjuvant, while 38 (45.2 %) patients took combination of NSAID
and adjuvant treatment. There was statistically significant (p = 0.000) reduction in VAS as time
progressed.
Conclusion: Cancer pain in pediatric age group can be well managed in accordance with the
WHO Analgesic Ladder. Aggressive symptoms and control of treatment of related side effect are
also needed to ensure successful implementation and the WHO Analgesic Ladder.
From Unit of Anesthesiology, Institute Rotary Cancer Hospital, All India Institute of Medial Sciences, Ansari Nagar, New Delhi,
India.
*
MD, Assist. Prof.
** MD, Assoc. Prof.
*** MD, Senior resident.
****MD, Senior Research Associate.
Corresponding address: Dr. Seema Mishra, Assist. Prof. Anesthesiology, F-33, AIIMS Residential Campus (West), Ansari
Nagar, New Delhi, Pin: 110029, India.
239
M.E.J. ANESTH 20 (2), 2009
240
Seema Mishra et. al
Introduction
The provision of pain management to the pediatric
oncology population presents special challenges. The
pediatric oncology population is chronically ill, often
young with a doubtful prognosis, labile disease course,
receiving aggressive therapy with a debilitating side
effects. Patients and their families experience severe
disruption to their daily lives with frequent clinic visits,
scheduled and unscheduled admission1. Although
there have been major advances in the treatment of
childhood cancer with on overall survival rate of more
than 70%, cancer continues to be the leading cause of
death in children resulting from disease2.
Pain control is an integral component of pediatric
palliative care. Children may experience many different
types of pain from invasive procedures, cumulative
effects of toxic therapies, progressive disease or
psychological factors.
The pain is often complex with multiple sources,
comprised of nociceptive and neuropathic components.
Children’s perception of pain is defined by their age and
cognitive level; their previous pain experiences, against
which they evaluate each new pain; the relevance of
the pain or disease causing pain; their expectation for
obtaining eventual recovery and pain relief and their
ability to control the pain themselves.
included general medical and neurological examination
and a specific examination of the site of pain and
surrounding anatomic regions. Patient who were lost
to follow up after single visit, were excluded from
this study. Patients were followed up weekly for three
weeks. Patients were asked to rate their global intensity
of pain on 0-100 mm visual analogue scale (VAS 0 no
pain and 100 mm is maximum pain)3.
Pain treatment was performed in accordance to
the WHO analgesic ladder for cancer pain:
• NSAIDs for mild pain (WHO Step 1),
• Weak opioids and NSAIDs for mild to moderate
pain (WHO Step 2),
• Morphine for moderate to severe pain (WHO
Step 3)4.
Every step was accompanied by various adjuvant
drugs for various indications (Table 1). All patients
were followed up weekly for three weeks.
Table 1
Various Adjuvant used in Pediatric Cancer pain
Types of Drugs
Drugs
Doses (mg/kg/
day)
Various
Indications
Antidepressant Amitriptiline
0.2-0.5
Neuropathic pain
Anticonvulsant Gabapentin
5-30
Neuropathic pain
Corticosteroids Dexamethasone
4-16 mg/day
In this study the pediatric cancer pain was managed
in accordance to the WHO analgesic ladder. The aim
was to collect data on the prevalence of different types
of cancer pain in a sample of children with cancer pain
and report on pain management in pediatric cancer
with respect to the WHO ladder approach at a regional
cancer set up.
Neuropathic pain
Bone pain, brain
metastasis
Poor quality of
life
Antiemetics
10-30 mg/day Nausea and
vomiting
0.5-0.15
0.01
Keywords: Cancer pain, Pediatric cancer pain,
Palliative care, WHO analgesic ladder.
Antihistamine Promethazine:
0.5-2
Diphenhydramine 1-4
Pruritus, Nausea/
vomiting
Laxatives
Constipation
Materials & Methods
The present study was conducted on outpatients
in the Pain and Palliative Care Clinic at Institute Rotary
Cancer Hospital, All India Institute of Medical Sciences,
New Delhi. India. 84 pediatric patients 5-15 years
(mean 11 yrs), (73% males, 27% females) suffering
of cancer pain were included in this prospective study
during the period 2001-2006.
Initial work up of patients in the Pain Clinic
Metoclopramide
Ondansetron
Granisetron
Bisacodyl
5-15 mg/day
Sodium
picosulphate
5-15 mg/day
Laxatives were given prophylactically to all
patients who were on opioids. In follow up visits,
patients were asked about pain intensity, nausea/
vomiting, sedation, constipation, generalized
weakness, lack of appetite. Patients were asked to
rate their symptoms on verbal rating score (VRS-1
not at all; 2 mild grades; 3 moderate grades; 4 severe
grades).
PEDIATRIC CANCER PAIN MANAGEMENT AT A REGIONAL CANCER CENTER: IMPLEMENTATION OF WHO
ANALGESIC LADDER
Statistical Analysis
The appropriate descriptive statistics were used
for presentation of each of the covariates. Exploratory
exercise was also done for applying the appropriate
statistical tools. One way analysis of variance was
used to compare the VAS among the different types
of pain. Kruskal Wallis test was used to compare the
age among the different types of pain. Chi square test
was performed to evaluate the association of various
outcomes at baseline with different types of pain.
Repeated measure of analysis of variance was used for
seeing the changes in the VAS as time increases as well
as effect of different types of pain (Neuropathic, mixed
and nociceptive pain). Cochran Q test was used to look
at the differences in proportion of nausea/vomiting,
constipation, sedation and pruritus as the time increases.
For seeing the changes in the generalized weakness
and loss of appetite as the time changes, Friedman test
was applied for each of the different types of pain. The
p-values less than 5% were considered as a significant
result. SPSS 11.5 was used for statistical analysis.
Results
Of the total 94 patients enrolled, 10 patients did
not turn up after 1st visit so were excluded. 84 patients
were followed up weakly for 3 weeks during the period
2001-2006.
52% of patients were referred from the medical
oncology, 30% patients from radiotherapy and 2%
patients from surgical oncology, whereas 16% patients
were direct referred to pain clinic.
Of the pediatric cancer patients studied 38%
had not taken any prior treatment 21% patients had
taken chemotherapy only, 19% patients had taken
chemotherapy and radiotherapy and 12% patients had
taken surgery, chemotherapy and radiotherapy prior to
referral.
241
Fig. 1
Patients distribution according to WHO steps at
different time point
WHO step 1 - Mild pain – NSAIDs
WHO step 2 - Mild to moderate pain – weak opioids + NSAID
WHO step 3 - Moderate to severe pain – morphine
In addition, at baseline, 40 (47.6%) patients took
NSAID only, 2 (2.4%) patients took adjuvant while
38 (45.2%) patients took combination of NSAID and
adjuvant treatment. The proportion of patients taking
combination of NSAID and adjuvant were increasing
continuously as time increased. The median morphine
dose at baseline, first and second weekly visits was
same i.e. 30 mg. However, median morphine dose at
third visit rose to 40 mg.
There was statistically significant (p = 0.000)
reduction in VAS as time increased while no effect
of different types of pain and no interaction effect
of time and different types of pain could be found
(Fig. 2).
Fig. 2
Pattern of VAS according to time
and different types of pain
26 (31%) patients had nociceptive pain (somatic,
bony, and visceral). 12 (14.3%) patients had neuropathic
pain, 46 (54.8%) patients had mixed pain (Table 2).
Almost 8.3% of pediatric patients were in the
WHO step 3 at baseline. Thereafter the WHO step
3 steadily increased at first weekly visit 36 (43%)
patients, second visit 58 (69%) patients, and third visit
69 (82.1%) (Fig. 1).
M.E.J. ANESTH 20 (2), 2009
242
Seema Mishra et. al
At baseline the nausea/vomiting was moderate
grade in 2 patients and severe grade in 1 patient. At
second weekly visit no patient had severe grade nausea/
vomiting while 6 patients had moderate grade nausea/
vomiting. Similarly, none of the patients had severe
grade constipation at any visit. 1 patient had pruritus at
baseline, 2 patients had moderate grade pruritus and 1
patient had severe pruritus at first visit. One patient had
moderate grade pruritus at second visit and no patients
developed any type of pruritus at third visit (Fig. 3).
Fig. 3
Distribution of various outcomes according to time
of symptom or no symptom was made for further
analysis. However, in case of generalized weakness
and loss of appetite, the level of severe grade (VRS
4) patients was less so that patients were pooled with
patients having VRS 3. The comparisons of baseline
characteristics are shown in Table 2.
The significant deterioration (p = 0.000) in
nausea/vomiting was found as time increased.
However no significant changes in the proportion of
patients could be seen in constipation. In addition, the
significantly increased changes in generalize weakness
was found whereas no significant changes were for
loss of appetite. There was no effect of different types
of pain on any of the outcomes separately.
Discussion
Pain control is an intrinsic component of pediatric
palliative care. Since children may experience complex
pains due to myriad physical and psychological factors,
pain control must be child centered rather than disease
centered5.
Since the number of patients presented with
nausea/vomiting or pruritus or constipation at any visit
was not much, therefore the category with occurrence
The management of pain in the palliative care of
children is somewhat different from that in adults. It
also differs in approach from the management of other
types of acute and chronic pain in childhood. But in
this present study it was found that pain management
Table 2
Patients characteristic at baseline according to different types of pain
Variables
Neuropathic (n = 12)
Mixed (n- = 46)
Nociceptive (n = 26)
p-values
Age (mean ± SD)
9.25 ± 4.49
10 ± 3.52
11.14 ± 3.03
0.256
Sex (M:F)
5:7
37:9
19:7
0.027
Visual analogue scale 77.5 ± 18.64
(VAS)
83.26 ± 16.33
80.38 ± 22.53
0.163
Nausea/Vomiting
5 (41.7%)
13 (28.3%)
12 (46.2%)
0.28
Constipation
3 (25%)
17 (37%)
12 (46.2%)
0.446
Sedation
2 (16.7%)
2 (4.3)
1 (3.8%)
0.237
Pruritus
0 (0.0%)
0 (0.0%)
1 (3.8%)
0.323
Generalized Weakness
Mild Weakness
Moderate Weakness
7 (58.3%)
1 (8.3%)
19 (41.3%)
2 (4.3%)
8 (30.8%)
4 (15.4%)
0.302
Loss of appetite
Mild
7 (58.3%)
Moderate
1 (8.3%)
n = Total number of patients.
20 (43.5%)
10 (21.7%)
9 (34.6%)
11 (42.3%)
0.182
PEDIATRIC CANCER PAIN MANAGEMENT AT A REGIONAL CANCER CENTER: IMPLEMENTATION OF WHO
ANALGESIC LADDER
in pediatric cancer pain according to WHO analgesic
ladder, is as good as in adult patients.
In the present study 14.3% patients were
having neuropathic, and 54.6% patients from mixed
(nociceptive and neuropathic) and 31.1% from
nociceptive pain. In adult patient’s the incidence of
neuropathic pain ranged from 16-31%, as quoted by
various authors6,7,8 but it is not clearly mentioned the
component of nociceptive in their population.
Mean pain intensity at base level in all types
was insignificant. There was statistically significant
reduction in VAS as time increased, while no effect of
different types of pain and no interaction effect of time
and different types of pain could be found. This study
therefore demonstrated that neuropathic pediatric
cancer pain can be relieved in most patients and the
efficacy of pediatric cancer pain treatment following
the WHO guideline was as good as in neuropathic
and mixed, as in nociceptive pain. It has previously
been thought that opioids were highly dangerous drugs
unsuitable for use in children. However, opioids have
now taken their place as the mainstay for provision
of good analgesia to manage moderate to severe pain
in malignant conditions9,10. Similar findings were
observed in the present study where at the end 82.1%
patients were on opioids as compared to 8.3% at base
line, and the mean dose of morphine used at the end of
study was 40 mg with statistically significant decrease
in VAS as compared to base line.
No extreme sedation or respiratory depression
was observed in any of our patient, similar to others9.
Itching was found in 2 children and out of these two
one was having itching before coming to our clinic
243
and another had itching after starting morphine which
subsided following antihistaminic therapy. Total of 6
(7.1%) patients had nausea/vomiting but out of these
six patients 2 patients had nausea/vomiting before
coming to our clinic, findings similar to findings
observed by Still et al9 but different from Kasai et al11,
as incidence of nausea and drowsiness were 52.9%
and 41.2% respectively. They proposed the two step
Analgesic Ladder.
Effective management of some difficult but
common pain syndromes such as shooting or burning
neuropathic pain, requires techniques “beyond the
ladder”. These patients require different classes of drugs,
such as tricyclic antidepressants and anticonvulsants.
Unfortunately many of these nonopioid adjuvant drugs
have not been studied in children and when prescribed,
are “off label”12.
The adjuvant analgesics comprise a diverse group
of medications with different primary indications like
antidepressants, anticonvulsants steroids13,14. Various
adjuvant drugs used in our study; amitryptiline,
gabapentine and corticosteroids, as was used by
various authors and found to be effective, though it
is not evidence based15,16. Future studies are therefore
needed to determine the effectiveness of these adjuvant
analgesics.
Conclusion
Cancer pain in pediatric age group can be very
well managed in accordance with the WHO analgesic
ladder. Aggressive control of related side effects, is
needed to ensure successful implementation of the
analgesic ladder.
M.E.J. ANESTH 20 (2), 2009
244
Seema Mishra et. al
References
1. Mark J Meyer: Integration of pain services in top pediatric oncology.
International Anaesthesiology Clinics; 2006, 44(1):95-107.
2. Hooke C, Hellsten MB, Stutzer C, Forte K: Pain management
for the child with cancer in end of life care: APON position paper. J
Pediatric Oncol Nurs; 2002, 20:43-47.
3. Ronald Melzack, Joel Katz: Pain measurements in persons in pain.
In: Patrick D. Wall, Ronald Melzack, Text book of pain; 4th eds.
London Churchill Livingstone, 1999, p. 409-26.
4. Ventafridda V, M Caraceni A, DeConno F, Naldi F: Validation
study of the WHO method for cancer pain relief. Cancer; 1997,
59:850-856.
5. Patricia A, McGrath, Stephen C Brown: Pediatric Palliative
medicine. In Derek Doyle, Geoffrey Hanks, Nathan Cherny and
Kenneth Calman. Oxford Text Book of Palliative Medicine; 3rd Eds,
2004, p. 775-89.
6. Twycross RG, Fairfield S Pain: In far advanced cancer. Pain; 1982,
14:303-10.
7. Ferrer-Brechner T: Treating cancer pain as a disease. In: C.
Benedetti CR Chapman. G. Morricca, JJ Bonica (Eds). Advances in
Pain Research and Therapy, vol. 7, Raven Press. New York, 1984,
575-91.
8. Banning A, Sjogren, Pand Henriksen H: Pain causes in 200 patients
referred to a multidisciplinary cancer pain clinic. Pain; 1991, 45:4548.
9. Sittl R, Richter R: Cancer Pain therapy in children and adolescent
using morphine. Anaesthesist; 1991, 40(2):96-99.
10.Hain RD, Miser A, Devins M, Wallace WH: Strong opioids in
pediatric palliative medicine. Pediatric Drugs; 2005, 7(1):1-9.
11.Kasai H, Saski K, Tsujinang H, Hoshino T: Pain management in
advanced pediatric cancer patients – a proposal of two step analgesic
ladder. Masui; 1995, 44(60):885-889.
12.Galloway KS, Yaster M: Pain and symptom control iin terminally
ill children. Pediatric Clinics North America; 2000, 47(3):711-46.
13.Sindrup S, Jensen T: Antidepressants in treatment of neuropathic
pain. In P. Hndsson, HL Fields & P. Marchettini (Eds). Neuropathic
pain: Pathophysiology and Treatment, Seattle, WA: IASP Press,
2001, p. 169-81.
14.Sindrup S, Jensen T: Efficacy of pharmacological treatment of
neuropathic pain: An update and effect related to mechanism of drug
action. Pain; 1999, 83:389-00.
15.World Health Organization: Cancer Pain relief. 2nd eds. with a guide
to opioid availability. Geneva 1996.
16.Yajnik S, Singh GP, Kumar M: Phenytoin as co analgesics in cancer
pain. J Pain Symptom Management; 1992, 7:209-13.
THE PROPHYLACTIC EFFECT OF RECTAL
ACETAMINOPHEN ON POSTOPERATIVE
PAIN AND OPIOID REQUIREMENTS AFTER
ADENOTONSILLECTOMY IN CHILDREN
Gholam Ali Dashti*, Shahram Amini**,
And Elham Zanguee***
Abstract
Background: Postoperative pain in children is common after adenotonsillectomy. Rectal
acetaminophen has been used effectively for postoperative pain management in small children.
The aim of this randomized double blind study was to evaluate the prophylactic effect of rectal
acetaminophen on postoperative pain management and opioid requirements in children undergoing
adenotonsillectomy.
Materials and Methods: 104 children, 7 to 15 yr, ASA I or II scheduled for elective
adenotonsillectomy were recruited for the study. Patients were randomized to receive either rectal
acetaminophen 40 mg/kg or nothing after induction of standard anesthesia. The postoperative pain
was assessed using visual analog scale (VAS) every 2 hours for the first 6 hours. The need for
rescue analgesic, intravenous pethedine of 0.5 mg/kg, was recorded at 24 hours after surgery.
Results: Pain scores were significantly lower in acetaminophen group at different times
(p<0.001) and needed less rescue analgesic (p<0.001).
Conclusion: We conclude that prophylactic rectal acetaminophen is effective in reducing
pain after adenotonsillectomy and postoperative analgesic requirement.
Key words: acetaminophen, analgesia, adenotonsillectomy, suppository.
From Zahedan Univ. of Medical Sciences, Zahedan, Iran.
*
MD, Assistant Professor of ENT.
** MD, Assistant Professor of Anesthesiology.
*** MD, General Practitioner.
Corresponding author: Shahram Amini MD, Ali-ebne-Abitaleb Hospital, Department of Anesthesiology, Khash Highway,
Zahedan, Iran. Tel: 0098 915 141 7235, Fax: 0098 541 3220504. E-mail: [email protected]
245
M.E.J. ANESTH 20 (2), 2009
246
Gholam Ali Dashti et. al
Introduction
Adenotonsillectomy is one of the most frequent
ENT operations performed in children with over 2
million cases in the United States1… and 2.3/1000 for
the population aged under 12 yr in the UK2 each year.
After approval from Research Committee of
Medical School and procuring parents informed
consent, 104 children, 7 to 15 yr, ASA I or II, to
undergoe elective adenotonsillectomy at a teaching
hospital, were recruited for the study. Exclusion criteria
included a known allergy to acetaminophen, renal or
hepatic dysfunction, ingestion of analgesics in the past
24 hours, drug abuse (because of high prevalence in the
region), a known case of G6PD deficiency, diarrhea,
dehydration, and bleeding disorders.
Postoperative pain may influence the child’s
ability to tolerate oral pain medication and fluid intake,
resulting in nausea3 and dehydration4 in a considerable
number of children postoperatively. Operation is
associated with pain in more than 80% of children on
the first day after operation5. It is assumed that pain
is not adequately treated in one half of all surgical
procedures6.
Although opioids are used widely in the
management of postoperative pain, their side effects
especially respiratory depression, bradycardia, nausea
and vomiting, have resulted in decreased use of these
analgesics especially in children.
Both acetaminophen and nonsteroidal antiinflammatory drugs (NSAIDs) have been used
extensively with very good results in reducing
pain and postoperative opioid requirements after
adenotonsillectomy in children1,7,8,9 and adults10.
NSAIDs act on prostaglandin synthesis for pain
reduction with adverse effects such as bleeding
problems in both gastrointestinal tract and from
the surgical site and potential renal dysfunction
that have caused some concerns in their widespread
application. Although some investigators have
shown their preference alone9 or in combination with
acetaminophen2,10, other studies failed to reveal such
an effect7,8,11. Acetaminophen is the most commonly
used analgesic in children. It is also frequently used
as an adjuvant for postoperative pain management in
pediatric patients2,8,10,12. However, there are reports that
failed to show any benefits in reducing postoperative
opioid requirements of rectal acetaminophen in infants
and small children undergoing elective cleft palate
repair13 or have showed that only high doses of rectal
acetaminophen of 40-60 mg/kg was effective in day
care surgery in children12.
The purpose of this randomized, double
blind study was to investigate the efficacy of rectal
acetaminophen on postoperative pain management
after adenotonsillectomy.
No premedication was used. After IV cannulation,
patients received 5 ml/kg crystalloid, 0.05 mg/
kg midazolam, and 1 µg/kg remifentanil. General
anesthesia was induced using 5 mg/kg thiopental
sodium. Atracurium (0.6 mg/kg) was used to facilitate
endotracheal intubation.
Following induction, the children were
randomized based on blocks of 10 to receive either
nothing (control group) (n = 51) or rectal acetaminophen
40 mg/kg (n = 53), by a surgical nurse who was blinded
to the study and did not participate in the postoperative
care of the child. Patients received a total of 10 ml/
kg of crystalloids intraoperatively. 0.2 mg/kg of IV
dexamethasone was given to reduce postoperative
nausea and vomiting. Anesthesia was maintained with
halothane 0.5-1% and remifentanil was used in doses
of 0.1-0.2 µg/kg/min to maintain heart rate and blood
pressure within 20% range from the baseline. Patients
were ventilated with 40% oxygen in nitrous oxide.
Standard monitoring included respiratory rate,
pulse rate, noninvasive blood pressure, and pulse
oximetry. At the end of the surgery, the residual
neuromuscular block was reversed with neostigmine
0.05 mg/kg IV, and atropine 0.2 mg/kg IV. All the
operations were performed by a single surgeon.
Patients were extubated when fully awake and were
transferred to postanesthetic care unit (PACU). No
patients received local anesthetics at the tonsillar
base and coagulation was achieved by electrocautery.
Patients were transferred to the ward if they were alert
and cooperative, with no or slight pain, no bleeding,
hemodynamically stable, and without nausea and
vomiting. They stayed in the hospital for 24 hours
postoperatively.
THE PROPHYLACTIC EFFECT OF RECTAL ACETAMINOPHEN ON POSTOPERATIVE PAIN AND OPIOID
REQUIREMENTS AFTER ADENOTONSILLECTOMY IN CHILDREN
Postoperative pain was assessed by using VAS by
trained independent blinded nurses on the ward (based
on a 0-100 scale) with 0 indicating no pain and 100
indicating the worst intolerable pain ever experienced.
Parents were also blind to the study. A pain score of
more than 40 was considered as unsatisfactory and
resulted in administration of 0.5 mg/kg of pethedine
IV (with the minimum interval of 4 hours).
Any adverse effects (nausea, vomiting, respiratory
depression, and bleeding) were recorded during their
stay in the hospital.
Differences between the groups were analyzed
using Student’s t-test. The chi-square test was applied
to non-parametric data. SPSS version 13 was used
for statistical analysis. P value less than 0.05 was
considered significant.
8.52) compared with the control group (17.09 mg SD
= 12.12), P value <0.001] (Table 3).
Table 2:
Postoperative pain scores
Acetaminophen
[score (SD)]
No
acetaminophen
[score (SD)]
P value
On arrival
to the ward
63.83 (25.30)
77.98 (17.94)
0.001
2 hours
45.64 (14.84)
69.35 (22.48)
<0.001
4 hours
32.66 (18.75)
46.60 (12.48)
<0.001
6 hours
23.05 (14.57)
50.25 (19.50)
<0.001
Table 3:
Postoperative pethedine requirements and number of patients
required rescue analgesic
Acetaminophen No
P value
[score (SD)]
acetaminophen
[score (SD)]
Results
There was no statistical difference in ASA
status, mean age, weight, and sex between the groups
(Table 1).
Table 1
Demographic data
Acetaminophen No acetaminophen P value
Age [year
(SD)]
10.16 (2.84)
9.45 (2.22)
0.15
Weight
(kg) (SD)
30.52 (9.32)
29.66 (6.40)
0.58
Sex (male/ 30/23
female)
34/17
0.29
ASA Status 36/27
(I/II)
33/28
0.31
The pain scores were significantly lower after
arrival at the ward in the acetaminophen group (63.83,
SD = 25.30 vs. 77.98, SD = 17.94, P value <0.002).
Patients in acetaminophen group experienced less pain
at 2, 4, and 6 hours postoperatively compared with the
control group (Table 2).
The number of patients who required rescue
analgesic was significantly higher in the control
compared with acetaminophen group (31 out of 51
vs 22 out of 53 P value <0.001). Opioid requirements
were less in the acetaminophen group (6.48 mg SD =
247
Postoperative
pethedine
requirements
(mg)
6.48 (8.52)
Number
22/53
of patients
required rescue
analgesic
17.09 (12.12)
<0.001
31/52
None of the patients in either group developed
significant bleeding requiring reoperation. No one
had respiratory depression, oxygen desaturation, and
bradycardia after receiving pethedine. Two patients
in the no acetaminophen group, developed nausea
and vomiting in the postoperative period requiring
intervention.
Discussion
Our study revealed that rectal acetaminophen
reduces pain intensity and postoperative analgesic
requirements
compared
to
group
without
acetaminophen after adenotonsillectomy. Our
study was in concordance with those using rectal
acetaminophen for postoperative pain management
after adenotonsillectomy..
Pain is a common complication after
adenotonsillectomy in children and results in 80%
M.E.J. ANESTH 20 (2), 2009
248
analgesic requirements5. Nikanne et, al showed that
more than 20% of children experienced severe pain
at home after adenotonsillectomy14. Pain removal
would result in less discomfort, nausea and vomiting,
faster postoperative oral intake and discharge from the
hospital.
It has been shown that postoperative oral pain
medication is difficult because children refuse to take
oral medication and may result in nausea, vomiting
and altered gastrointestinal motility. On the other hand,
preventing the initial neural cascade could lead to
long term benefits by eliminating the hypersensitivity
produced by noxious stimuli15.
Although opioids are used widely in the
management of postoperative pain, their adverse
effects such as respiratory depression and nausea
and vomiting have reduced their application. Non
steroidal anti-inflammatory drugs (NSAIDS) have
replaced opioids for postoperative pain management
because of lack of respiratory depression and nausea
and vomiting16,17. However, their side effects such as
increasing bleeding tendency from the surgical site and
gastrointestinal tract, GI upset, and renal and hepatic
dysfunction, may affect their liberal application.
Tawalbeh et, al9 suggested that diclofenac was
more effective than paracetamol in decreasing the pain
associated with swallowing after adenotonsillectomy
without
considerable
adverse
effects.
In
contradistinction, Rusy et al7 showed that ketorolac
was no more effective than high dose acetaminophen
for analgesia in the patient after tonsillectomy.
Acetaminophen is the most commonly used
analgesic in children. It is almost safe and effective
in comparison to opioids and NSAIDS. Rectal
acetaminophen has been shown to be a good alternative
to oral administration in postoperative pediatric
Gholam Ali Dashti et. al
adenotonsillectomy patients. However, doses as high
as 40-60 mg/kg could be satisfactorily effective12.
Bremerich et, al reported that acetaminophen up to 40
mg/kg had no opioid sparing effect and did not result
in analgesia13.
In contrast to our findings, previous studies have
found that rectal acetaminophen may provide erratic
and inconsistent analgesia after tonsillectomy18,19,20
This variation may be explained by differing analgesic
requirements with different surgical techniques,
different doses of acetaminophen, or the concurrent
use of other analgesic agents. In addition is the type
of surgery performed as adenotonsillectomy might be
more painful than adenoidectomy alone.
Acetaminophen has been shown to be more
effective when combined with NSAIDs in the
postoperative pain management2,10,8,11.
Combination of NSAIDs and other analgesics
have been proposed for pain management17 but there is
not a general agreement on their efficacy. Issioui et al
concluded that oral premedication with a combination
of acetaminophen (2000 mg) and celecoxib (200 mg)
was highly effective in decreasing pain and improving
patient satisfaction after ambulatory ENT surgery10.
However, Hiler et al8 have shown that a combination of
paracetamol and diclofenac was not more effective than
paracetamol alone for analgesia after tonsillectomy.
In summary, we were able to show that rectal
acetaminophen in dose of 40 mg/kg is effective in
reducing pain intensity and postoperative analgesic
requirements after adenotonsillectomy in children.
It is recommended to administer prophylactic
rectal acetaminophen in order to decrease the
child’s postoperative discomfort and pain after
adenotonsillectomy.
THE PROPHYLACTIC EFFECT OF RECTAL ACETAMINOPHEN ON POSTOPERATIVE PAIN AND OPIOID
REQUIREMENTS AFTER ADENOTONSILLECTOMY IN CHILDREN
249
References
1. Owezarzak V, Haddad J: Comparison of oral versus rectal
administration of acetaminophen with codeine in postoperative
pediatric adenotonsillectomy patients. Laryngoscope; 2006,
116:1485-88.
2. Pickering AE, Dridge HS, Nolan J, Stoddart PA: Double-blind
placebo-controlled study of ibuprofen or rofecoxib in combination
with paracetamol for tonsillectomy in children. Br J Anaesth; 2002,
88:72-77.
3. Lee WC, Sharp JF: Complications of pediatric tonsillectomy postdischarge. J Laryngol Otol; 1996, 110:136-140.
4. Mc Callum PL, MacRae FL, Sukerman S, MacRae E: Ambulatory
adenotonsillectomy in children less than 5 years of age. J
Otolaryngol; 2001, 30:75-78.
5. Kokki H, Ahonen R. Pain and activity disturbance after pediatric day
care adenotonsillectomy. Pediatr Anest; 1997, 7:227-31.
6. Carr DB, Jacox AK, Chapman CR, Ferrell B, et al: Clinical
practice guidelines for acute pain management: operative or medical
procedures and trauma. Washington DC: agency for health care
policy and research, 1992; DDHS publication no. 95-0034.
7. Rusy LM, Houck CS, Sullivan LJ, Ohlms CB, et al: A double
blind evaluation of ketorolac tromethamine versus acetaminophen
in pediatric tonsillectomy: analgesia and bleeding. Anesth Analg;
1995, 80:226-9.
8. Hiller A, Silvanto M, Savolainen S, Tarkkila P: Propacetamol
and diclofenac alone and in combination for analgesia after elective
tonsillectomy. Acta Anaesthesiology Scand; 2004, 48:1185-89.
9. Tawalbeh MI, Nawaresh OO, Husban AM: Comparative study
of diclofenac sodium and paracetamol for treatment of pain after
adenotonsillectomy in children. Saudi Medical Journal; 2001,
22(2):121-123.
10.Issioui T, Klein KW, White PF, Watcha MF, et al: The efficacy of
premedication with celecoxib and acetaminophen in preventing pain
after otolaryngologic surgery. Anesth Analg; 2002, 94:1188-93.
11.Viitanen H, Tuominen N, Vaaraniemi H, Nikanne E, Annila P:
Analgesic efficacy of rectal acetaminophen and ibuprofen alone
or in combination for pediatric day-care adenotonsillectomy. Br J
Anaesth; 2003, 91:363-7.
12.Korpela R, Korvenoja P, Meretoja OA: Morphine-sparing effect of
acetaminophen in pediatric day-care surgery. Anesthesiology; 1999,
91(2):442-7.
13.Bremerich DH, Neidhart G, Heinmann K, Kessler P, Benhe M:
prophylactically-administered rectal acetaminophen does not reduce
postoperative opioid requirements in infants and small children
undergoing elective cleft palate repair. Anesth Analg; 2001, 92:90712.
14.Nikanne E, Kokki H, Tuovinen K: postoperative pain after
adenotonsillectomy in children. Br J of Anaesth; 1999, 82(6):886-9.
15.Gottschalk A, Smith DS: New concept in acute pain therapy:
preemptive analgesia. Am Fam Physician; 2001, 63:1979-84.
16.Recart A, Issiouri T, White PF, Watcha MF, et al: The efficacy of
celecoxib premedication on postoperative pain and recovery times
after ambulatory surgery: A dose-ranging study. Anesth Analg; 2003,
96:1631-5.
17.Kehlet H, Dahl JB: The value of multimodal or balanced analgesia
in postoperative pain management. Anesth Analg; 1993, 77:104856.
18.Gaudreault P, Guay J, Nicol O, Dupuis C. Pharmacokinetics and
clinical efficacy of intrarectal solution of acetaminophen. Can J
Anaesth; 1988, 35:149-52.
19.Anderson B, Kanagasundarum S, Woollard G. Analgesic efficacy
of paracetamol in children using tonsillectomy as a pain model.
Anaesth Intensive Care; 1996, 24:669-73.
20.Viitanen H, Tuominen N, Vaaraniemi H, Nikanne E, Annila P.
Analgesic efficacy of rectal acetaminophen and ibuprofen alone or
in combination for paediatric day-case adenoidectomy. Br J Anaesth;
2003, 91:363-7.
M.E.J. ANESTH 20 (2), 2009
PREGNANCY AT TERM DOES NOT ALTER
THE RESPONSES TO A MECHANICAL
AND AN ELECTRICAL STIMULUS
AFTER SKIN EMLA APPLICATION
Amalia Katafigioti*, Anteia Paraskeva**,
Georgios Petropoulos***, Ioanna Siafaka***
and A rgyro Fassoulaki ****
Abstract
Background: Pregnancy is associated with reduced local anesthetic requirements and
increased pain thresholds, possibly due to hormonal changes and activation of endogenous
opioids.
Methods: We compared the responses to a mechanical and an electrical stimulus in 30 pregnant
women (pregnant group) scheduled for cesarean section and 30 healthy female volunteers (control
group) matched for age. Pain was assessed by Visual Analogue Scale (VAS) on two different days
after skin application of EMLA or placebo cream on the forearms. EMLA and placebo cream were
randomly applied on the medial surface of both forearms for 30 min in a blind cross over manner
and the subjects received a mechanical stimulus generated through a pressor palpator followed by
an electrical stimulus generated through a nerve stimulator.
Results: Average VAS values from both trials did not differ between pregnant and control
group exposed to the mechanical or electrical stimulus after EMLA application or after mechanical
or electrical stimulus after placebo cream application..
Conclusions: Late pregnancy is not associated with increased sensitivity to local anesthetics
(EMLA) applied to the skin, under our study conditions.
Key words: pregnancy, pain perception, mechanical stimulus, electrical stimulus, local
anesthesia; EMLA.
From the Department of Anesthesiology, Aretaieion Hospital, Medical School, University of Athens, Athens, Greece.
*
Fellow.
** Lecturer.
*** Assoc. Prof.
****Prof. & Chairman.
Correspondence author: A. Paraskeva, 39A Kleomenous Street, 10676 Athens, Greece. Tel: +30210-7247955. E-mail:
[email protected]
251
M.E.J. ANESTH 20 (2), 2009
252
Introduction
Decreased local anesthetic requirements during
regional analgesia1,2,3, increased sensitivity to local
anesthetics4 and increased pain thresholds have all
been reported during pregnancy5,6. Mechanical factors
such as increased lumbar lordosis7 and/or distension
of the epidural veins8, or hormonal alterations, such as
increased progesterone and estrogen levels, have been
implicated to explain the above changes9,10.
The present study was designed to investigate in
pregnant women of 38 weeks of gestation the response
to a mechanical and an electrical stimulus after skin
application of Eutectic Mixture of Local Anesthetics
(EMLA). These responses were compared to the
responses obtained from nonpregnant young women
treated similarly.
Study population
After Institutional Review Board approval and
patient written informed consent, 30 parturients ASA
I-II with singleton pregnancy (24 primiparas and
6 multiparas) of completed 38 weeks of gestation
scheduled for elective cesarean section, and 30 healthy
female volunteers matched for age range, were enrolled
in this prospective study. Exclusion criteria consisted of
body weight more than 20% of the ideal body weight
for volunteers and more than 20 Kg weight gain during
pregnancy for parturients, complicated pregnancy,
thyroid gland disease, central or peripheral nerve
disease, diabetes mellitus, hypertension, analgesic
consumption or illegal drug abuse, alcoholism and
non-Greek speaking language.
Study protocol
The mechanical and electrical stimuli were
demonstrated to all participants and the Visual
Analogue Scale (VAS) was explained the day before.
Tests were performed by the same investigator (A.K)
on two consecutive days in both the parturients and the
controls. All subjects were tested in the sitting position
in a quiet room during the morning hours.
Day 1: An independent anesthesiologist filled
syringes of 2 ml with EMLA, or placebo creams, and
applied these on the medial surface of the forearm in the
Amalia Katafigioti et. al
middle of the distance between the wrist and the elbow.
Both creams were covered with Tegaderm™ tape. The
forearm right versus left to receive EMLA cream was
determined by tossing a coin, heads indicating EMLA
application on the right and tails on the left forearm.
Thirty minutes later the creams were removed and the
responses to a mechanical and electrical stimulus were
assessed by Visual Analogue Scale (VAS).
Day 2: Both parturients and control subjects were
exposed to the same tests on the following day but in a
reverse order regarding EMLA and placebo application
on the right versus the left forearm.
Unless contraindicated, epidural analgesia
was the technique of choice. Mechanical and
Electrical Stimuli.
Mechanical stimulus was applied for 3 sec by a
pressure palpator (Pressure Feeler 650 gr Sedatelec®;
Chemin des Muriers, Irigny, France)11,12,13 exerting a
standard force on its end of 650 gr. This was followed
by an electrical stimulus consisted of a 2Hz, 0.25
msec square wave electrical impulse, generated by a
peripheral nerve stimulator (Organon®).
The primary endpoint of our study was the VAS
scores obtained in pregnant and nonpregnant women
after applying a mechanical and an electrical stimulus
on the skin exposed to EMLA and to placebo cream.
Statistical analysis was conducted using the
SPSS version 13.0 (SPSS Inc., Chigago IL). Patient
characteristics between the two groups were compared
with Student’s t-test and smoking habit was analyzed
with X2 test.
VAS scores obtained after EMLA application
on the right and left forearm of the same subject were
averaged. Similarly were treated VAS scores after
placebo cream.
VAS scores obtained after mechanical and
electrical stimuli following EMLA application as well
as VAS scores obtained after mechanical stimulus
following placebo cream application did not follow
a normal distribution (Kolmogorov-Smirnov test)
and were compared between the groups with MannWhitney test. VAS scores after electrical stimulus
following placebo cream followed normal distribution
PREGNANCY AT TERM DOES NOT ALTER THE RESPONSES TO A MECHANICAL AND AN ELECTRICAL
STIMULUS AFTER SKIN EMLA APPLICATION
(Kolmogorov-Smirnov test) and were compared
between the two groups with Students t-test.
Results
Patients’ characteristics in each group are shown
in Table 1. Weight was significantly higher in the
parturient women compared to the control group (p
= 0.0005). Twenty one of the parturients received
epidural anesthesia and 9 received general anesthesia.
Table 1
Demographics and smoking in the pregnant and control group.
Values are mean(sd)
Pregnant
(Ν = 30)
Controls
(Ν = 30)
p
Age (years)
32.6(3.7)
31.6(4.8)
0.338
Body
Weight(kg)*
77.6(10.4)
61.4(1.3)
0.0005
Height (m)
1.66(0.06)
1.66(0.07)
0.338
12(40.0)
18(60.0)
7(23.3)
23(76.7)
0.165
Smoking
Yes
No
Table 2
VAS scores after application of a mechanical and an electrical
stimulus in their forearms where the pregnant and the controls
were treated with EMLA and placebo cream. Values are
mean(sd)
Mechanical
Electrical
Pregnant
Controls
p
Z
EMLA
20(18)
19(10.8)
0.58 -0.54
Placebo
20(14.5)
19(11.8)
0.883 -0.14
EMLA
26(22)
24(16.6)
0.853 -0.18
Placebo
21.4(15)
17(10.1)
0.21
Animal studies have shown that pregnancy results
in a progressive increase of pain thresholds5,6 possibly
due to activation of endogenous opioid system14 and to
steroid hormone elevation10. Nevertheless these results
have not been reproduced in human studies in the same
consistent manner. Staikou et al., in a similar setting as
in our study, found no difference between pregnant and
control subjects regarding pain responses to mechanical
and electrical stimuli11. Also Dunbar at al., reported no
differences in VAS scores after nociceptive thermal
stimuli before or after pregnancy, although no control
group was investigated15. Coolkasian et al., found that
pregnant women are more willing to report pain than
non pregnant subjects16. Saisto et al., reported reduced
pain tolerance and increased VAS scores after cold
pressor test in pregnant women fearing labor pain than
pregnant women not fearing labor pain. All subjects
reported increased VAS scores before than after
delivery but no change in pain endurance17.
In contrast Cogan et al., reported increased pain
thresholds, after a pressure stimulus, before delivery
than after delivery and increased discomfort thresholds
between pregnant and controlled subjects18.
The VAS values did not differ between the two
groups after the mechanical or electrical stimulus
regardless of treatment with EMLA or placebo cream
(Table 2).
Stimulus
253
t
1.24
Discussion
The results of the present study failed to show
increased sensitivity of, pregnant women to topical
EMLA application compared to non pregnant women,
as assessed by pain perception after mechanical or
electrical stimuli.
Also electrical stimuli of 5, 250 and 2000 Hz have
resulted in increased pain thresholds during pregnancy
with greatest reduction observed at 5Hz stimulation.
Nevertheless no control group was included in this
study and the study population was small19. Carvalho
et al., in a recent controlled study found increased
heat pain tolerance in pregnant women a finding not
reproduced by cold pressor stimulus20.
The controversial results in humans might be
attributed to lack of control group in most studies, to
different stimuli used to access the pain perception,
to different time points of testing, but also to
interindividual variability21.
Enhancement of local anesthetic effects has been
also documented during pregnancy, and although the
reason is not clear, hormonal and mechanical factors
have been investigated. Datta et al, found decreased
latency of conduction block of nerve fibers from
pregnant rabbits to bupivacaine, suggesting either
increased sensitivity or enhanced diffusion to receptor
site due to increased progesterone levels during
pregnancy4. Flanagen et al in two studies showed that
chronic exposure of rabbit nerve fibers to progesterone
M.E.J. ANESTH 20 (2), 2009
254
Amalia Katafigioti et. al
alters local anesthetic sensitivity22,,23.
Long term exposure to progesterone might play
the key role as Bader et al, could not find an effect of
acute progesterone treatment in conduction blockade
of isolated rabbit vagus nerve24. Hirabayashi et al.,
found that pregnancy at second, third trimester and at
term, enhances the spread of hyperbaric amethocaine
compared to nonpregnant or to first trimester
pregnant women, which again supports the role of
progesterone rather than mechanical factors producing
these changes3. Progesterone alterations have also
been proposed to explain the decrease halothane25,
enflurane26 thiopental requirements during pregnancy27
although the mechanism remains unknown.
Nevertheless, mechanical factors cannot be
excluded to explain subarachnoid block alterations
during pregnancy. James et al., in a non blinded
study, have shown increased anesthetic requirements
in preterm women (28-35 weeks of gestation) than at
term women (38-42 weeks of gestation) presenting for
cesarean section28. They also found a strong correlation
between fundal height taken from the symphysis pubis
to the fundus and the block height achieved. Fassoulaki
et al, found higher level of subarachnoid sensory block
with hyperbaric lidocaine in pregnant compared to non
pregnant women2.
Our results are in contrast to the results of
Butterworth et al., who found increased susceptibility
of the median nerve to 5 ml of 1% lidocaine HCL in
pregnant women29. We chose EMLA cream which
penetrates the intact skin and successfully obliterates
pain during pinprick30, so the local anesthetics used
in Butterworth and in our study are not comparable.
Eogan et al., found prolonged median nerve latencies
in pregnant compared to non pregnant subjects which
might be the underlying reason of the results of
Butterworth31.
A limitation of our study is the short time of
EMLA application (30 min), as it has been shown that
increased time of application or increased time between
removal of the EMLA and stimulus application results
in more effective blockage of nociceptive receptors as
assessed with laser stimulus32,33.
In conclusion, the response to a mechanical and
an electrical stimulus after EMLA or placebo cream
application to the skin, did not differ between pregnant
and non-pregnant women.
PREGNANCY AT TERM DOES NOT ALTER THE RESPONSES TO A MECHANICAL AND AN ELECTRICAL
STIMULUS AFTER SKIN EMLA APPLICATION
255
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M.E.J. ANESTH 20 (2), 2009
ROBOTIC LAPAROSCOPIC RADICAL CYSTECTOMY
INHALATIONAL VERSUS TOTAL INTRAVENOUS
ANESTHESIA: A PILOT STUDY
Mohamed M. Atallah* and Mahmoud M.
othman **
Summary
Background: Robotic assistance may refine laparoscopic radical cystectomy. Steep
Trendelenburg tilt (TT) and pneumoperitoneum (PP) are challenging anesthesia maneuvers. In
view of those maneuvers, would inhalational anesthesia or total intravenous anesthesia (TIVA)
be the more appropriate anesthetic management for this kind of surgery?. This issue is under
consideration in this clinical trial.
Methods: 15 patients scheduled for robotic laparoscopic radical cystectomy (RLRC) were
randomly allocated into two groups to be anesthetized by either isoflurane anesthesia (ISO n = 8)
or ketamine-midazolam-fentanyl total intravenous anesthesia (TIVA n = 7). The hemo-respiratory
dynamics, oxygenation and biochemical variables were monitored taking into consideration the
system organ function as primary outcomes, and operative conditions and recovery profile as
secondary outcomes.
Results: The PP and TT increased the mean arterial and airway pressures and decreased lung
compliance, and were associated with respiratory acidemia, while changes in heart rate remained
within normal range. The duration of PP was shorter in TIVA patients but mean arterial pressure was
higher than ISO group. ISO was associated with increased plasma concentrations of prothrombin,
fibrinogen and aspartate aminotransferase.
Conclusions: Though the number of patients is small in this study (n = 15), it nevertheless
brings to light the advantages of TIVA during the robotic laparoscopic radical cystectomy (RLRC),
by shortening the duration of PP without an increase in prothrombin and fibrinogen concentrations.
A larger number of clinical trial are needed to further clarify this issue..
Keywords: anesthesia, inhalation, isoflurance; anesthesia, intravenous, ketamine, midazolam,
fentanyl; surgery, radical cystectomy.
From Urology and Nephrology Center, University of Mansoura, Mansoura, Egypt.
*
MD, Professor of Anaesthesia.
** MD, Professor of Anaesthesia.
Corresponding author: MM. Atallah, Urology and Nephrology Center, University of Mansoura, Mansoura, Egypt. Phone:
002050 2262222, Fax: 002050 2263717. E-mail: [email protected]
257
M.E.J. ANESTH 20 (2), 2009
258
Introduction
Advances in instrumentation and surgical
techniques are expanding the application of
laparoscopic approaches to the extended operation of
radical cystectomy1. Robotic assistance has helped to
refine laparoscopic radical prostatectomy2, and may do
the same for laparoscopic radical cystectomy. Placing
the patient in an extended lithotomy position with a
45º Trendelenburg tilt (TT) and pneumoperitoneum
(PP) inflation are technically needed, but challenging
physiological side effects due to the widespread
changes in body system organs3-5 may ensue.
Patients subjected to radical cystectomy are
usually elderly adults or more. Perioperative risk
factors include preexisting system organ dysfunction,
PP, head down position, anesthetics, surgical stress,
hypovolemia, and possibly any other iatrogenic
intervention. Perioperative optimization of the vital
functions and minimization of postoperative pain,
therefore, are mandatory in order to avoid further
deterioration of preexisting diseases.
Ketamine-midazolam
total
intravenous
anesthesia (TIVA) during radical cystectomy has been
recommended6,7. Whether inhalational anesthesia
will be more favourable technique during robotic
laparoscopic radical cystectomy (RLRC) is difficult
to speculate and this issue is explored in our modest
clinical study.
In this limited number of our clinical trial, patients
scheduled for RLRC were randomly allocated to either
isoflurane anesthesia (ISO n = 8), or to ketaminemidazolam-fentanyl total intravenous anesthesia (TIVA
n = 7). Monitoring system organ function as primary
outcomes and operative condition and recovery profile
as secondary outcomes, were noted.
The study protocol was approved by the
Institutional Review Board (IRB) and a patient written
informed consent obtained.
A controlled randomized study was carried out
with 15 patient scheduled for RLRC and bladder
substitution.. All RLRC were performed by the same
anesthetic and surgical teams8.
Mohamed M Atallah et. al
On the morning of surgery, patients were
premedicated with 7.5 mg midazolam and 300 μg
clonidine given orally two and one hour respectively,
before transfer to the operative suite. These doses
were reduced by 50% to patients ≥60 years old.
Patients were allocated by computer generated random
numbers to receive either isoflurane anesthesia (ISO n
= 8) or ketamine-midazolam-fentanyl total intravenous
anesthesia (TIVA n = 7).
Age-adjusted single dose upper lumbar extradural
analgesia was performed in the sitting position in both
groups before induction using bupivacaine 0.5% mixed
with morphine. Arterial and central venous cannulation
were secured.
The ISO group was induced with 1 μg/kg-1
fentanyl, 0.1 mg/kg-1 midazolam and sleeping dose of
thiopentone and maintained by isoflurane at end-tidal
concentrations adjusted to help minimizing changes in
HR and arterial BP.. The TIVA group was induced with
fentanyl 1 μg/kg-1, midazolam 100 μg/kg-1 and ketamine
2 mg/kg-1 and maintained by separate infusion of the
three drugs (Table 1). Before creation of PP, ketamine
dose was reduced by 25%, and midazolam and fentanyl
doses were reduced by 50%. These were normalized
following the creation of PP. Pipecuronium was used to
facilitate tracheal intubation in both groups to maintain
adequate surgical muscle relaxation and was replaced
by vecuronium when repeated serum creatinine level
was >1.5 mg/dL-1. The lungs were ventilated with
oxygen enriched air (FIO2 = 0.35) and ventilation was
manipulated to minimize excessive increases in endtidal CO2 concentrations.
After induction, the patients were placed in an
extended lithotomy position with a 45º TT. Sufficient
padding was applied around the shoulder and pressure
points and the arms were tucked in.
Following RLRC, the resected bladder specimen
was removed though a mini-subumbilical laparotomy
incision. A neobladder was then fashioned from the
terminal ileum. The ureters were re-implanted to the
neobladder. The latter was relocated into the pelvis.
The wound was then closed. Finally, the neobladder
was then anastomised to the urethral stump via
laparoscopic approach.
ROBOTIC LAPAROSCOPIC RADICAL CYSTECTOMY INHALATIONAL VERSUS TOTAL INTRAVENOUS
Table 1
The infusion regimens of the components of ketaminemidazolam-fentanyl
total intravenous anesthesia (TIVA)
Ketamine
Midazolam
Fentanyl
(μg/kg-1
(μg/kg-1 h-1)
(μg/kg-1
min )
h )
-1
-1
First hour
30
40
1.0
Second hour
25
35
1.0
Third hour
20
30
0.75
Fourth hour
15
20
0.75
Fifth hour
10
15
0.5
Wound closure
5
10
0.5
If anesthesia was longer than 5h, the drug infusion rate during
the sixth hour was the same as the fourth, and the seventh hour
similar to the fifth hour. This sequence could be repeated if
deemed necessary.
Monitoring consisted of continuous 5-lead
ECG, pulse oximetry, capnography, invasive
arterial pressure, central venous pressure, core body
temperature and respiratory dynamics. Arterial blood
samples were periodically withdrawn for gasometry,
Hb conc, Hct%, and biochemical variables (albumin,
bilirubin, transaminases, creatinine, fibrinogen and
prothrombin conc.). Plasma cortisol and growth
hormone concentrations were respectively quantified
by fluorescence polarization immunoassay (Axsym,
USA) and enzyme-linked immuno-sorbant assay
(DSL, USA).
The increases in HR and arterial pressure induced
by the creation of pnemoperitoneum (PP) and steep
Trendelenberg tilt (TT) were ameliorated by the
stepping up anesthesia concentration and infusion of
nitroglycerine and sodium nitroprusside. Warming
was carried out throughout the procedure. Cautious
initially restricted fluid replacement was achieved
by warm crystalloids. Residual neuromuscular block
was antagonized with neostigmine at the end of the
operation. In the recovery room, patients were observed
and their physiological signs assessed.
Data were processed by SPSS program
and presented as median and SD. For intergroup
significance evaluation Mann-Whitney U-Wilcoxon
rank sum test was used. For significance of differences
259
from the basal values, Wilcoxon-matched pairs signed
ranks test was used. P-value <0.05 was considered
statistically significant.
Results
This prospective randomized clinical trial was
performed with 15 patients who underwent RLRC and
open surgery neobladder creation. Patient demographic
data and durations of operative interventions are
displayed in Table 2.
The median durations of PP and RLRC were
shorter during TIVA by 32% and 36% respectively.
HR changes did not display any significant
difference between both groups (Fig. 1). PP and TT
increased MBP in both groups, with more higher
values in TIVA patients. Following PP deflation, MBP
returned to within normal range in both groups (Fig.
1). Stepping up anesthetic doses prevented excessive
increases in BP in five and two patients in ISO and
TIVA respectively. Nitroglycerine infusion (0.5-10
μg/kg-1 min-1) was needed in the rest of the patients.
Two patients in TIVA needed additional sodium
nitroprusside (0.5-2 μg/kg1 min-1).
Table 2
Patients data and durations of operative intervention
Values are median ± SD (range).
Isoflurane
TIVA
(n = 8)
(n = 7)
Demographic data:
Age (y)
58 ± 7 (47-66)
56 ± 5 (50-63)
Body weight (kg)
71 ± 10 (54-80)
80 ± 14 (58-95)
Body height (cm)
167 ± 24 (105-181) 170 ± 4 (165-175)
Gender (M/F)
6/2
7/0
Duration of intervention (h)
Trendelenburg tilt
4.4 ± 0.7 (2.8-5.2)
3.8 ± 0.5 (3.0-4.5)
Pneumoperitoneum 4.0 ± 0.8 (2.4-4.8)
2.7 ± 0.8 (1.9-4.0)*
Robotic cystectomy 3.6 ± 0.8(2.1-4.5)
2.3 ± 0.8 (1.5-3.8)*
Open surgery
3.5 ± 1.0 (1.8-4.5)
4.0 ± 0.6 (3.0-4.5)
Total anesthetic
8.8 ± 0.8 (8.0-10.0) 8.0 ± 0.5 (7.3-8.8)*
duration
* Significant intergroup difference (P <0.05)
Preoperative condition: 3 hypertensives in TIVA group, 1
diabites mellitus in TIVA group, 6 C-virus hepatitis, 4 in
isoflurane group and 2 in TIVA group.
M.E.J. ANESTH 20 (2), 2009
260
Mean airway pressure was increased, and lung
compliance was decreased following PP creation
and TT. However, following deflation, TIVA patients
showed higher lung compliance values (Fig. 1).
PP produced respiratory acidemia which
gradually resolved postoperatively (Fig. 2). Plasma
albumin decreased in all patients during the 7 days
study period, while prothrombin and fibrinogen
increased only following ISO (Fig. 3). Serum
aspartate aminotransferase (AST) increased on the
third postoperative day following ISO, but serum
bilirubin and alanine aminotransferase were within
normal values (Fig. 4). Serum sodium, potassium, and
creatinine were within normal ranges during the study
period.
Growth hormone and cortisol increased in all
patients during operative intervention (Table 3). By
the end of surgery, growth hormone returned to normal
values in TIVA patients, but remained high following
ISO. Cortisol levels remained high in both groups.
Intraoperative blood loss was minimal in 13 patients.
One patient in each group needed two units of blood.
Recovery was delayed for 60 min in one patient
following ISO and for 45-150 min in 5 patients
following TIVA. The latter needed pressure support
ventilation. Surgical emphysema affecting the
medial aspects of the thighs and lower abdomen was
observed in 4 and 3 patients following ISO and TIVA
respectively. This extended to the face in one patient in
each group. Periorbital edema was observed. Patients
did not complain of pain from the surgical incisions
and postoperative analgesics were needed for patients
with extended surgical emphysema. There was no
incidence of pneumothorax, pneumomediastinum,
pulmonary edema or any other system organ affection
during the postoperative period.
Discussion
RLRC was performed with limited number
of patients anesthetized by either ISO or TIVA. The
creation of PP and TT increased mean arterial and
airway pressures and decreased lung compliance, and
was associated with respiratory acidemia, while changes
in HR remained within normal range. The duration of
PP was shorter in TIVA patients but MBP was higher
than ISO group. ISO was associated with increased
plasma concentrations of prothrombin, fibinogen and
AST. Recovery was more delayed following TIVA.
Peritoneal insufflation with carbon dioxide and
modification in patient position with 45º TT were applied
to provide adequate visual and operative conditions.
PP induces widespread changes in cardiovascular
system. Experimental data demonstrated a decrease
in cardiac output and MBP9,10. Elevated preload and
afterload and decreased cardiac output and ejection
fraction were reported in clinical studies3,11-13. Head
Table 3
Serum growth hormone and cortisol following isoflurane anesthesia (ISO, n =8 )
and ketamine-midazolam-fentanyl total intravenous anesthesia (TIVA, n =(7
Values are median ± SD (range)
Growth hormone
(mg/ml-1)
Cortisol
(μg/ml-1)
ISO
TIVA
ISO
TIVA
0.1 ± 0.3
(0.1-1.0)
0.4 ± 0.9
(0.1-2.6)
11.3 ± 4.6
(3.6-18.3)
12.8 ± 12.2
(8.8-42.3)
8.0 ± 7.1*
(0.8-21.0)
3.2 ± 4.5*
(0.9-12.0)
32.7 ± 14.0*
(20.4-56.7)
36.0 ± 17.6*
(6.4-60.0)
Open surgery
1.2 ± 1.3*
(0.4-3.6)
1.1 ± 1.0
(0.3-3.1)
31.2 ± 12.0*
(7.2-46.0)
35.0 ± 12.6*
(25.2-60.0)
Postoperative (2h)
0.5 ± 0.9
(0.1-2.2)
1.1 ± 1.7
(0.3-5.1)
28.5 ± 15.0*
(17.8-60.0)
32.4 ± 13.8*
(21.7-60.0)
Basal
End of:
Robotic cystectomy
* Significant difference (P<0.05) from basal value.
261
Fig. 1
Perioperative median values of mean blood pressure (MBP,
mmHg), heart rate (HR, bpm), compliance (Comp., ml/cm
H2O), and mean air way pressure (Paw, CmH2O) during
isoflurane anesthesia (ISO) and TIVA.
Fig. 3
Postoperative median serum concentrations of prothrombin,
Fibrinogen, and albumin after isoflurane anesthesia (ISO) and
TIVA
Fig. 2
Perioperative median values of pH, arterial carbon dioxide
tension (PaCO2, mmHg), and serum bicarbonate (HCO3,
mmol/L) during isoflurane anesthesia (ISO) and TIVA
Fig. 4
Postoperative median serum concentrations of bilirubin,
Aspartate aminotransferase (AST), and Alanine
aminotransferase (ALT) after isoflurane anesthesia (ISO)
and TIVA
M.E.J. ANESTH 20 (2), 2009
262
down position either increased these changes3,11 or had
no more effect12, but none of these clinical studies had
adopted this steep TT.
Respiratory acidosis and decreased lung
mechanics together with transient reduction of the
pulmonary shunt were demonstrated after PP in clinical
settings5,13.
The cerebral blood flow velocity increased and
the cerebral vascular resistance decreased, while
maintaining the vasoreactivity unaffected14-16.
During pneumoperitoneum, the blood flow to
the abdominal organs is variably affected. Hollow
viscus organs are less disturbed than solid organs10.
Experimental data demonstrated a decrease in total
hepatic blood flow, mostly through a decrease in portal
vein blood flow, with contradictory reports on hepatic
artery buffer response9,10,17,18. Cirrhotic liver showed a
similar decrease in total hepatic blood flow19. Clinical
studies reported a decrease in hepatic blood flow and
increase in hepatic enzymes, being more following
cholecystectomy than after colectomy, suggesting
impairment of hepatic function specially in elderly
patients4,20. PP and hypovolemia markedly alter renal
blood flow21. In our study, abdominal organ function
was not affected apart from mild increase in AST
following ISO.
Most experimental studies investigating the
effects of PP on “organ function” have been conducted
mostly on small animals without organ disease, while
the majority of the clinical reports were young adults
and mostly with healthy system organs. With RLRC,
the denominator is different. Patients are likely to
be elderly adult or older, sicker and with significant
underlying disease demonstrating lower threshold
for physiologic decompensation. Perioperative risk
factors include preexisting system organ dysfunction,
hypovolemia and possibly any other iatrogenic
intervention. Risk-adjusted strategy should be
adopted. Preexisting disease have to be optimally
managed. Perioperative optimization of vital functions
and minimization of postoperative pain avoid further
deterioration of preexisting diseases. PP pressure and
the degree of head down have to be the least compatible
with good surgical conditions. Adequate anesthesia and
prompt replacement of fluid and blood loss minimize
the surgical stress response.
Inhalational anesthetics have a cardioprotective
effect. This has been reported in vitro studies22,23, and
clinically in coronary surgery patients24. In this pilot
study, ISO anesthesia was followed by increased plasma
concentrations of prothrombin, fibrinogen and AST
suggesting incomplete stress and hepatic protection.
The clinical advantages of TIVA during radical
cystectomy has been recommended6, 7. It provided
better operating conditions and a more acceptable
recovery profile. The absence of significant changes in
plasma concentrations of prothrombin, fibrinogen and
AST following TIVA suggests a satisfactory stress and
hepatic protection.
Which of the two techniques is more favourable
for RLRC is still speculative. The results of this limitednumber clinical trial do not equate to that coming from
reasonably powered study. Although the duration of PP
was shorter in TIVA patients and the measured plasma
concentrations of the coagulation factors were within
normal range, yet a definite advantage for TIVA would
be claimed following a clinical trial with adequate
number of patients.
In conclusion, the study is limited in number and
the patients were carefully chosen from cancer bladder
population to be of appropriate age and body weight
with minimal organ system dysfunction. While this
study refers to an advantage of TIVA during RLRC,
yet a large number clinical trial are needed to confirm
these advantages.
Acknowledgment: We acknowledge the
statistical analysis by Mrs Sahar A. Rahman,
Statistician at the Urology & Nephrology Center.
263
References
1. Hemal AK, Singh I: Cost reduction laparoscopic radical cystectomy
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Surgeons; 2001, 5:143.
2. Tewari A, Peabody JO, Sarle R, Hemal AK, Shrivastava A,
Menon M: Technique of da Vinci robot-assisted anatomic radical
prostatectomy. Urology; 2002, 60:569-72.
3. Hirvonen EA, Nuutinen LS, Kaudo M: Hemodynamic changes
due to Trendelenberg positioning and pneumoperitoneum during
laparoscopic hysterectomy. Acta Anaesthesiol Scand; 1995, 39:94955.
4. Kotake Y, Takeda J, Matsumoto M, Tagawa M, Kikuchi H:
Subclinical hepatic dysfunction in laparoscopic cholecystectomy
and laparoscopic colectomy. Brit J Anaesth; 2001, 87:774-7.
5. Andersson L, Lagerstrand L, Thorne A, Sollevi A, Brodin
LA, Odeberg-Wernerman S: Effect of Co2 pneumoperitoneum
on ventilation-perfusion relationships during laparoscopic
cholecytectomy. Acta Anaesthesiol Scand; 2002, 46:552-6.
6. Atallah MM, El-Mohayman HA, El-Metwally RE: Ketaminemidazolam total intravenous anaesthesia for prolonged abdominal
surgery. Eur J Anaesthesiol; 2001, 18:29-35.
7. Shorrab AA, Atallah MM: Total intravenous anesthesia with
ketamine-midazolam versus halothane nitrous oxide oxygen
anaesthesia for prolonged abdominal surgery. Eur J Anaesthesiol;
2003, 20:925-31.
8. Menon M, Hemal AK, Tewari A, et al: Nerve-sparing robot-assisted
radical cystoprostatectomy and urinary diversion. Brit J Urol Int;
2003, 92:232-6.
9. Ishizaki Y, Bandai Y, Shimomura K, Abe H, Ohtomo Y, Idezuki
Y: Changes in splanchnic blood flow and cardiovascular effects
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!0.Schafer M, Sagesser H, Reichen J, Krahenbuhl L: Alterations
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11.Odeberg S, Ljungqvist O, Svenberg T, et al: Haemodynamic
changes due to Trendelenberg positioning and pneumoperitoneum
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12.Rist M, Hemmerling TM, Rauh R, Siebzehnrubl E, Jacobi KE:
Influence of pneumoperitoneum and patient positioning on preload
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changes during open carbon dioxide pneumoperitoneum and
abdominal wall-lifting cholecystectomy. A prospective, randomized
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14.De Cosmo G, Lannance E, Primieri P, et al: Changes in cerebral
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15.Erkan N, Gokmen N, Goktay AY, et al: Effects of Co2
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K: Preserved Co2 reactivity and increase in middle cerebral arterial
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Analg; 2002, 94:255-8.
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Effects of carbon dioxide pneumoperitoneum on hemodynamics in
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M.E.J. ANESTH 20 (2), 2009
THE EFFECT OF NITROGLYCERIN AS AN ADJUVANT
TO LIDOCAINE IN INTRAVENOUS
REGIONAL ANESTHESIA
Rahman Abbasivash*, Ebrahim Hassani*,
Mir Moussa Aghdashi**,
and M ohammad S hirvani ***
Implication Statement
The present study is the second to assess nitroglycerin as a new adjuvant for intravenous
regional analgesia. Its addition to lidocaine, nitroglycerin appears to shorten the sensory and motor
block onset time in closed reduction of forearm fractures and provides acceptable analgesia for 24
hours after operation.
Abstract
Purpose: The disadvantages of intravenous regional anesthesia (IVRA) include slow onset,
poor muscle relaxation, tourniquet pain, and rapid onset of pain after tourniquet deflation. In
this randomized, double-blind study, we evaluated the effect of nitroglycerin (NTG) in quality
improvement when added to lidocaine in IVRA.
Methods: Forty-six patients (20‑50 yrs), were randomly allocated in two equal groups. Under
identical condition, the control group received a total dose of 3mg/kg of lidocaine 1% diluted with
saline, and the study group received an additional 200 µg NTG. Vital signs and tourniquet pain,
based on visual analog scale (VAS) score were measured and recorded before and 5, 10, 15, 20, and
30 min after anesthetic solution administration. The onset times of sensory and motor block were
measured and recorded in all patients. After the tourniquet deflation, at 30 min and 2, 4, 6, 12 and
24h, VAS score, time to first analgesic requirement, total analgesic consumption in the first 24 h
after operation, and side effects were noted.
Results: The sensory and motor block onset time were shortened in study group (2.61 vs.
5.09 and 4.22 vs. 7.04 min, respectively) (p <0.05). The recovery time of sensory and motor block
and onset of tourniquet pain were also prolonged (7.26 vs. 3.43, 9.70 vs. 3.74 and 25 vs. 16.65min.,
respectively) (p <0.05). Analgesia time after tourniquet deflation was prolonged and tourniquet
pain intensity was lowered in study group (p <0.05). Intraoperative fentanyl and meperedine
requirement during first postoperative day and pain intensity at 4, 6, 12 and 24 hr postoperatively
were lower in the study group (p <0.05). There were no significant side effects.
From Department of Anesthesia, Emam Hospital, Urmia Medical Science University, Iran.
*
MD, Assistant Professor.
** MD, Anaesthesiologist, Fellow in Pain Management.
*** MD, Anesthesiologist.
Corresponding author: Ebrahim Hassani, Emam Hospital, Urmia Medical Sciences University, Urmia, Iran.
E-mail:[email protected]
265
M.E.J. ANESTH 20 (2), 2009
266
Conclusion: The NTG adding to lidocaine in
intravenous regional anesthesia shortens onset times of
sensory and motor block and decreases the tourniquet
and postoperative pain, without any side effect.
Keywords: Intravenous regional anesthesia,
Nitroglycerin, Lidocaine.
Introduction
The technique of intravenous regional anesthesia
(IVRA) was first introduced by German surgeon
August Bier in 19081. It consists of injecting local
anesthetic solutions into the venous system of an
upper or lower extremity that has been exsanguinated
by compression or gravity and that has been isolated
by means of a tourniquet from central circulation. The
resultant anesthesia is produced by direct diffusion
of local anesthetic from the vessels into the nearby
nerves. This technique is easy, cost-effective and its
efficacy in emergency and out patients setting has
been proved2.
Complications of IVRA are a few and mostly
limited to systemic toxicity from local anesthetic that is
related to problems with the technique. The risk mainly
comes from an inadequate tourniquet application or
equipment failure at the beginning of the procedure.
Its slow onset, tourniquet pain during the
procedure, limited operating time (<1 h), possible
nerve damage and insufficient postoperative analgesia
are among a few disadvantages of this technique.
Analgesic effects of transdermal Nitro-glycerin
(NTG) have been reported in several studies3,4,5,6,7,8
and recently Nitro-glycerin has been used as an
adjuvant in IVRA and its effects on tourniquet pain
and intraoperative and postoperative analgesia were
promising9. We decided to conduct a similar study
in patients scheduled for close reduction of forearm
fracture and evaluate the duration of analgesic effect
for 24 hours postoperatively.
The essence of science implies that study findings
must be replicated in a different study before firm
conclusion can be drawn. Thus, the present study is
the second to assess the efficacy and safety of using
Nitroglycerin in IVRA as an adjuvant.
Rahman Abbasivash et. al
Informed patient consent and ethical and research
committees approval were obtained. In a prospective
, radomised double-blinded study , forty six ASA
I – II patients age 20-50 years scheduled for closed
reduction of forearm fractures were included in two
equal groups. The sample size was calculated based
on a type I error of α = 0.05, p1/p2 equal to 2.75 and p
2 = 0.15. Enrollment of 23 patients in each group was
required. Patients with sickle cell anemia, Reynaud
disease, and history of drug allergy, antihypertensive
drug and NTG consumption were excluded.
In operating room, patient’s vital signs (arterial
blood pressure, heart rate, SpO2, ECG) were monitored
by Datascope passport 2. Premedication for both
groups consisted of IV midazolam 0.15 mg/kg and 1
µg/kg fentanyl. An intravenous cannula (gauge 20)
was placed in a distal vein of the hand in preparation
for IVRA. The arm was elevated for six minutes then
a rubber Esmarch bandage was wound around the arm
spirally to exsanguinate the arm. A double pneumatic
tourniquet was placed around the upper arm and
the proximal cuff was inflated based on LOP (Limb
Occlusion Pressure) with safety margin of about 50
mmHg.
Absence of radial pulse and loss of pulse
oximetry tracing was considered as an adequate
isolated circulation of the arm. In study group IVRA
was administered with 200 µ NTG, (Trinitrosan 5
mg/1ml, Merck KGaA, Darmstadt, Germany) plus 3
mg/kg lidocaine (LIGNODIC®. Lidocaine 1%, Caspian
Tamin Pharmaceutical Co., Rasht-Iran)) diluted with
saline to a total volume of 40 ml. In control group 3
mg/kg lidocaine diluted with saline to the same volume
was injected over 60 seconds by an anesthesiologist
blinded as to group assignments.
To assess the sensory block, pinprick with a
22 gauge short-beveled needle was performed in the
dermatomal sensory distribution of median, ulnar and
radial nerves. Complete motor block was noted when
no voluntary movement in patients wrist and fingers
was possible. Sensory and motor block onset times
were recorded.
After the onset of sensory and motor block, distal
cuff of tourniquet was inflated to 250 mmHg and the
EFFECT OF NITROGLYCERIN AS AN ADJUVANT TO LIDOCAINE IN INTRAVENOUS REGIONAL ANESTHESIA
proximal cuff was deflated. BP, HR, SpO2 and Visual
Analog Scale (VAS) scores (0 = no pain and 10 worst
pain) was monitored before and at 5, 10, 15, 20, 25, 30
min after tourniquet deflation. When pain was >3 on the
VAS scale, patients were given intravenous fentanyl 1
µg/kg. Times and total dose of intraoperative fentanyl
were recorded. Tourniquet was not deflated sooner than
30 min. At the end of surgery through cyclic deflation
technique, it was deflated. Sensory and motor block
recovery time was noted. Vital signs and pain intensity
(VAS) were monitored 30 min and 2, 4, 6, 12 and 24 h
postoperatively. Patients with VAS >3 received 30 mg
IM meperedine and the total dose of meperedine in first
24 hour after surgery was recorded. Quantitative and
qualitative data were analyzed by Independent sample
student’s t-test and Fischer’s exact χ2 test respectively.
Results
The demographic data in both groups were
similar and no significant difference was noted (p
>0.05, Table 1).
Table 1. Patient characteristics
Table 1:
study group took longer time to complain of tourniquet
pain and analgesia lasted longer in study group (25.00
vs. 16.65 and 130.32 vs. 38.21 min, respectively) (p
<0.05, Table 2).
Although there was no significant difference in
pain intensity 15 minutes from the start of operation,
yet during the next 15 minutes pain intensity and
tourniquet pain, determined by VAS was lower in study
group compared to control group (p <0.05).
The average dose of intraoperative IV fentanyl in
study group was less than control one (18.26 vs. 78.04
micg, respectively, p <0.05) (Table 3). The average pain
intensity in 4, 6, 12 and 24 hour postoperation in study
group was less compared to control group (p <0.05) but
maximum pain intensity in first day postoperatively
as determined by VAS, was similar in both groups
(p <0.05). In study group intramuscular meperedine
injection (35.42 mg) was also less compared to control
group (55.65 mg) (p <0.05) (Table 3).
No adverse effect was noted in both groups.
Discussion
Patient Characteristic
variable
Study G
Control G
Age(yr) ± SD
33.83 (±10.66)
34.57 ( ±12.83)
Sex (F/M) ± SD
4F/19M
5F/18M
Weight(Kg) ± SD
72.30 (±9.57)
79.35 (±18.04)
ASA I/II
18 I / 5 II
16 I / 7 II
*. Independent samples Student’s t-test, **. Fischer’s exact χ2 test.
267
P-Value
0.833*
0.713 **
0.105 *
0.507 **
The same surgeon performed surgical procedure
(closed reduction of forearm fracture). There was
no statistically significant difference in vital signs
(MAP, HR) in both groups intraoperatively and after
tourniquet deflation (p >0.05).
The onset time of sensory and motor block in the
study group were shorter (2.65 vs. 5.09 and 4.22 vs.
7.04min, respectively, p <0.05) and the recovery time
for sensory and motor block were slower (7.26 vs. 3.43
and 9.07 vs. 3.74 min, respectively) (p <0.05). The
The results of this study suggest that the addition
of NTG to lidocaine for IVRA in closed reduction of
forearm fractures, without any notable side effects,
improved the onset and duration of sensory and motor
block and anesthesia quality, decreased tourniquet pain
in terms of both onset and duration and intraoperative
and postoperative analgesic consumption.
Several studies have reviewed the use of adjuncts
(i.e., opioids, non steroid anti-inflammatory drugs10,
α2 agonists11,12 neostigmine13, muscle relaxants,
magnesium14 and sodium bicarbonate) to intravenous
regional anesthesia. Selda Sen et al performed the first
study on adding NTG to IVRA for hand and forearm
surgery such as tendon release, trigger point and carpal
Table 2
Onset and recovery times of sensory and motor block and duration of analgesia after tourniquet deflation
Variable
Study G
Control G
Sensory block onset time (min)
2.65 (± 0.99)
5.09 (± 1.86)
Sensory block recovery time (min)
4.22 (± 0.99)
7.04 (± 1.87)
Motor block onset time (min)
7.26 (± 1.42)
3.43 (± 0.99)
Motor block recovery time (min)
9.07 (± 1.14)
3.74 (± 0.91)
Analgesia duration after tourniquet deflation 130.52 (± 37.61)
(min)
Values are mean ± SD, p-values were <0.0001
38.22 (± 21.65)
M.E.J. ANESTH 20 (2), 2009
268
Rahman Abbasivash et. al
Table 3
Pain intensity, Tourniquet pain onset time, Intraoperative fentanyl consumption
and postoperative meperidine 24h postoperation in two groups.
† p-value <0.0001.
* Independent Samples T-Test.
tunnel15. The results of this study on closed reduction of
forearm fractures were very similar to the results obtained
by Selda Sen et al. They reported that pain intensity in
NTG group was low in 4 hour postoperative follow-up.
Our study showed that in 24 hour postoperative followup, pain intensity in study group was less than control
group. But there was no significant difference in worst
pain expressed as VAS in both groups.
It seems that because of the type and nature of
the injury (forearm fracture) maximum VAS in both
groups was similar. The clinical efficacy of transdermal
NTG for improving pain control has been documented
in several studies. NTG was useful in cancer pain
management16,17 enhancing intrathecal analgesia18,19
epidural ketamine20 and chronic pain management21.
Transdermal NTG applied 2 h before performing
IVRA with prilocaine 2%, had significant benefit in
both sensory and motor block22.
These beneficial effects of NTG may come
from its strong vasodilatory effects that causes rapid
distribution of lidocaine to nerves and this would
explain the rapid onset of sensory and motor block.
Intracellular metabolism of NTG to nitric oxide (NO)
increases intracellular concentration of cyclic guano
sine monophosphate (cGMP) which causes pain
modulation in central and peripheral nervous system.
Topical application of NTG has anti-inflammatory
effects and analgesia by blocking hyperalgesia and
the neurogenic component of inflammatory edema
through NO production.
Direct stimulation of peripheral fibers, similar
to locally applied acetylcholine is another possible
mechanism for analgesic effect of NTG. The above
mentioned mechanisms or combination of them, might
contribute to the analgesic effects of NTG added to
lidocaine in IVRA.
NTG as an adjuvant in IVRA, nearly halves the
onset of sensory and motor block, which has beneficial
effects in patients managed by IVRA.
NTG increases the onset time of tourniquet pain
and reduces its intensity. It seems that although high
doses of NTG can cause hypotension and headache but
no adverse effect was noted with small doses added to
lidocaine.
Conclusion
The results of this study suggest that with addition
of NTG to lidocaine in IVRA improves the quality
of the block, decreases tourniquet pain and opioid
consumption in first postoperative day. Further study
might be undertaken to evaluate the local anesthetic
sparing effect of NTG in IVRA.
EFFECT OF NITROGLYCERIN AS AN ADJUVANT TO LIDOCAINE IN INTRAVENOUS REGIONAL ANESTHESIA
269
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Livingstone. Philadelphia, Pennsylvania, 2005, 573-604.
3. Lauretti GR, Perez MV, Reis MP, Pereira NL: Doubleblind evaluation of transdermal nitroglycerine as adjuvant
to oral morphine for cancer pain management. J Clin
Anesth; 2002, 14(2):83-6.
4. Lauretti GR, Lima IC, Reis MP, Prado WA, Pereira NL:
Oral ketamine and transdermal nitroglycerin as analgesic
adjuvants to oral morphine therapy for cancer pain
management. Anesthesiology; 1999, 90(6):1528-33.
5. Lauretti GR, de Oliveira R, Reis MP, Mattos AL, Pereira
NL: Transdermal nitroglycerine enhances spinal sufentanil
postoperative analgesia following orthopedic surgery.
Anesthesiology; 1999, 90(3):734-9.
6. Lauretti GR, OliveiraAP, Julião MC, Reis MP, Pereira NL:
Transdermal nitroglycerine enhances spinal neostigmine
postoperative analgesia following gynecological surgery.
7. Lauretti GR, Oliveira AP, Rodrigues AM, Paccola CA:
The effect of transdermal nitroglycerin on spinal S(+)ketamine antinociception following orthopedic surgery. J
Clin Anesth; 2001, 13(8):576-81.
8. Glantz L, Godovic G, Lekar M, Kramer M, Eidelman
LA: Efficacy of transdermal nitroglycerin combined with
etodolac for the treatment of chronic post-thoracotomy
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Symptom Manage; 2004, 27(3):277-81.
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The analgesic effect of nitroglycerin added to lidocaine
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An evaluation of the analgesic efficacy of intravenous
regional anesthesia with lidocaine and ketorolac using a
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95:457-460.
11. Reuben SS, Steinberg RB, Klatt JL, Klatt ML:
Intravenous regional anesthesia using lidocaine and
clonidine. Anesthesiology; 1999, 91(3):6548-.
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regional anesthesia. Anesth Analg; 2004, 98:835-40.
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Z: Intravenous regional anesthesia using prilocaine and
neostigmine. Anesth Analg; 2002, 95:1419-1422.
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Z: Intravenous regional anesthesia using lidocaine and
magnesium. Anesth Analg; 2005, 100(4):1189-92.
15. Sen S, Ugur B, Aydın ON, Ogurlu M, Gursoy F, Savk O:
The analgesic effect of nitroglycerin added to lidocaine
on intravenous regional anesthesia. Anesth Analg; 2006,
102:916-20.
16. Lauretti GR, Perez MV, Reis MP, Pereira NL: Doubleblind evaluation of transdermal nitroglycerine as adjuvant
to oral morphine for cancer pain management. J Clin
Anesth; 2002, 14(2):83-6.
17. Lauretti GR, Lima IC, Reis MP, Prado WA, Pereira NL:
Oral ketamine and transdermal nitroglycerin as analgesic
adjuvants to oral morphine therapy for cancer pain
management. Anesthesiology; 1999, 90(6):1528-33.
18. Lauretti GR, de Oliveira R, Reis MP, Mattos AL, Pereira
NL: Transdermal nitroglycerine enhances spinal sufentanil
postoperative analgesia following orthopedic surgery.
19. Lauretti GR, OliveiraAP, Julião MC, Reis MP, Pereira NL:
Transdermal nitroglycerine enhances spinal neostigmine
postoperative analgesia following gynecological surgery.
20. Lauretti GR, Oliveira AP, Rodrigues AM, Paccola CA:
The effect of transdermal nitroglycerin on spinal S(+)ketamine antinociception following orthopedic surgery. J
Clin Anesth; 2001, 13(8):576-81.
21. Glantz L, Godovic G, Lekar M, Kramer M, Eidelman
LA: Efficacy of transdermal nitroglycerin combined with
etodolac for the treatment of chronic post-thoracotomy
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M.E.J. ANESTH 20 (2), 2009
EVALUATION OF THE TOURNIQUET LEAK
DURING FOREARM INTRAVENOUS
REGIONAL ANESTHESIA
- Manual vs Automatic Pump Injection -
Roshdi Roshdi Al-Metwalli*
Summary
Background: The present study was conducted to compare the effect of pump injection
versus manual injection on the venous pressure, during forearm intravenous regional anesthesia
(IVRA) and the incidence and the magnitude of lidocaine leak, .
Methods: A crossover randomized study of IVRA with a forearm tourniquet was conducted
on 14 male healthy volunteers. This study was performed, once using manual injection of local
anesthetic and once using automatic pump injection, on two separate sessions. In both techniques,
0.3 ml/kg lidocaine 0.5% was injected over 90 seconds. The occlusion pressure, continuous venous
pressure and the serum lidocaine two minutes at end of injection, were recorded.
Results: The mean occlusion pressure 161.6 (17.2) mmHg was always higher than the mean
initial arm systolic blood pressure 131.711. The maximum venous pressure was significantly higher
in the manual technique 176.7 (15.4) mmHg than in the pump technique 161.3 (12.3) mmHg (p
= 0.04). The incidence of lidocaine leak was significantly lower (35.71%) in the pump technique
compared to (78.5%) in the manual technique (p = 0.02). Moreover; the mean lidocaine plasma
concentrations was significantly higher [0.86 (0.5) µg.ml-1] in the manual technique compared to
[0.32 (0.4) µg.ml-1] the pump technique (p = 0.04).
Conclusion: The use of pump injection for forearm IVRA could significantly decrease the
maximum venous pressure, and decrease the incidence and the magnitude of lidocaine leak past
the tourniquet.
Keywords: Anesthetic technique: regional intravenous. Drug: lidocaine. Measurements:
Venous pressure, Lidocaine plasma conc.
*
Assist Prof. of Anaesth. & IC, King Faisal Univ., Al-Khobar, Saudi Arabia.
Correspondence: Dr. Roshdi Roshdi Al-Metwalli, King Fahad Hospital of University. P.O. Box: 40081, Post Code 31952,
Al-Khobar, Saudi Arabia, E-mail: [email protected]
271
M.E.J. ANESTH 20 (2), 2009
272
Roshdi Roshdi Al-Metwalli
Introduction
Intravenous regional anesthesia (IVRA) is a safe
and effective technique for providing anesthesia as well
as a bloodless field during hand surgery, with published
success rates ranging from 94% to 98%1,2. IVRA is
easy to perform and the only necessary technical skill
is inserting an intravenous (IV) cannula.
Traditionally, an upper arm tourniquet has been
used for these procedures. However, the recommended
doses of local anesthetics for upper arm IVRA do have
the potential risk of systemic toxicity3,4.
Forearm IVRA, however, allows the dose of
local anesthetic to be decreased by up to 50% without
affecting the quality of analgesia5,6. In addition, the
forearm tourniquet can be tolerated longer and was
consistently rated as less painful when compared with
the upper arm tourniquet7. However, this technique
was unpopular in the past because it was thought that
“compression forces of an inflated forearm tourniquet
cannot obliterate the anterior and posterior interosseous
arteries seated in the deep ‘valley’ between the
prominent radius and ulna”8. It was therefore assumed
that tourniquet leakage was inevitable, thus increasing
the possibility of local anesthetic toxicity and block
failure. A quantitative study showed that forearm
IVRA results in tourniquet leakage comparable with
upper arm IVRA9.
During intravenous regional anesthesia, leakage
of local anesthetic agent past the tourniquet into the
systemic circulation could occur if the tourniquet
pressure was inadequate to maintain occlusion of the
underlying vessels in the face of the venous pressures
generated by the injection10. Previous studies had
measured venous pressure during actual or simulated
upper arm IVRA, at different injection rates and
volumes. To my knowledge, limited data of using
automatic pump injection for forearm IVRA are
available.
The main objective of the present trial is to study
venous pressure during lidocaine forearm IVRA, using
manual versus automatic pump injection, and evaluate
its effect on the possible leak past the tourniquet.
Following the Institutional Ethics Committee
approval and volunteer informed written consent,
a prospective randomized study of IVRA with a
forearm tourniquet was conducted on 14 male healthy
volunteers, each volunteer acting as his own control.
This study was performed, once using manual injection
of local anesthetic and once using automatic pump
injection, on two separate sessions. The sequence of
the technique of IVRA (manual or pump technique) for
each session, was allocated randomly and separated by
at least one week.
For each session, immediately before the start of
the procedure, arterial blood pressure was measured
in the contra lateral arm with a standard adult cuff
using a mercury sphygmomanometer. An 8 cm wide
pneumatic tourniquet was placed over padding on
the forearm 1 cm below the medial epicondyle of
the humerus. An automatic pneumatic tourniquet
machine (Zimmer A.T.S. 2000) was used for inflating
the pneumatic tourniquet. The gauge on the machine
was calibrated against a mercury column before each
operating session.
“Occlusion pressure”, the tourniquet pressure
required to occlude the radial blood flow was
measured. This was determined by slowly lowering
the tourniquet pressure from well above the systolic
value and recording the tourniquet pressure at which
the radial pulse first became palpable. Having found
the occlusion pressures, the pneumatic tourniquet
was removed and placed in a similar manner over the
forearm to be operated on. A 20-gauge Teflon catheter
was inserted in a dorsal vein of the hand and used for
injection of local anesthetic. A similar cannula was
inserted in a vein just distal to the tourniquet for venous
pressure recording during the injection. The limb distal
to the pneumatic tourniquet was exsanguinated by an
Esmarch’s bandage, starting from the finger tips. The
tourniquet was then inflated to a pressure equal to the
occlusion pressure plus 50 mmHg (inflation pressure),
and the Esmarch’s bandage was removed.
The calculated amount of 0.5 per cent
preservative-free lidocaine solution (0.3 ml.kg-1 body
weight) was injected over 90 second in all volunteers,
by either the same anesthesiologist (manual technique)
or by using automated infusion pump [Baxter Flogard.
FAAM.3047K] (pump technique), through the
intravenous cannula on the dorsum of the hand. Venous
EVALUATION OF THE TOURNIQUET LEAK DURING FOREARM INTRAVENOUS REGIONAL ANESTHESIA
273
pressure distal to the tourniquet was recorded every 10
seconds during injection by another anesthesiologist
using pressure transducer connected to the proximal
venous catheter.
plasma concentrations was 0.86 (0.5) µg.ml-1 in the
manual technique and 0.32 (0.4) µg.ml-1 in the pump
technique with significant difference between both
techniques (P <0.04).
In all patients two venous blood samples were
taken for estimation of lidocaine concentration from
an indwelling intravenous catheter placed in the
contra lateral upper limb, before and two minute after
lidocaine injection. The tourniquet was deflated 15
minutes after injection.
Venous pressure before exsanguinations, before
and during injection is presented in Fig. 1. There was
a significant difference between the maximum venous
pressure in the manual technique 176.7 (15.4) mmHg
and in the pump technique 161.3 (12.3) mmHg (p =
0.02).
Statistics
The sample size was determined assuming a
paired design in which forearm IVRA using different
mode of injection would be applied to each volunteer
on two separate occasions. To have an 80% probability
of detecting 17% difference (from a pilot study) of
maximum intravenous pressure, between the two
techniques ([beta] = 0.2), and testing at the 0.05 level
([alpha] = 0.05), the sample size was found to be 14
patients. Data was analyzed using a paired t-test to
compare venous pressure and lidocaine serum level.
Fisher’s exact test was used to compare the incidence
of leak. Statistical significance was assumed to be
achieved at P <0.05.
Results
The mean age of the volunteers was 33.7 (7.7)
yr, mean height was 172.3 (7.2) cm, mean weight was
74.7 (5.1) kg and the mean forearm circumference was
25.9 (3.2) cm.
The occlusion pressure 161.6 (17.2) mmHg
was always higher than the initial arm systolic blood
pressure 131.7 (11) mmHg and the difference between
them which ranged from 5 to 50 mmHg (29 ± 12.6) did
not show any correlation with either the initial systolic
blood pressure measured over the upper arm, (R2 =
0.008), or the circumference of the forearm at a point
1 cm distal to the medial epicondyle of the humerus
(R2 = 0.03).
There was significant difference in the incidence
of lidocaine leak past the pneumtic cuff into the
systemic circulation prior to tourniquet release,
between the manual technique 11/14 (78.5%) and the
pump technique 5/14 (35.71%) p = 0.02. The lidocaine
There was significant correlation between the
maximum venous pressure and the lidocaine plasma
levels in both manual (Fig. 2) and pump techniques
(Fig. 3) (R2 = 0.82 and 0.68 respectively).
Discussion
The present crossover randomized study, showed
a significant higher value of venous pressure during
forearm IVRA when using manual injection than when
using pump injection, with significant lower incidence
and magnitude of the leak (lidocaine plasma level) in
the pump group compared to the manual group.
One important factor affecting the success of
IVRA is the tourniquet pressure. The present study used
8 cm wide pneumatic cuff, which is much narrower
than the standard adult sphygnomanometer cuff used
for measuring blood pressure. As the narrow cuff is less
able to transmit tourniquet pressure to blood vessels
lying deep inside the limb11,12, this could explain why
the occlusive pressure was always higher than systolic
blood pressure. Similarly this could explain why the
difference between them was smaller in the present
study 29.6 (12.6) mmHg using 8 cm wide cuff than
Chan, et al study 67 (25) mmHg using 5 cm wide
cuff5.
In the present study, the highest venous pressure
was observed at the end of injection in both techniques,
with significant higher value in the manual injection
technique. This could be expected, as the use of
infusion pump for injection could induce a steady rise
of venous pressure given a chance for the veins to
distend over the time with a final lower pressure at the
end of injection.
To my knowledge none of the previous studies
had evaluated the effect of using pump injection versus
M.E.J. ANESTH 20 (2), 2009
274
Fig. 1
Evaluation of venous pressure for the
manual ( ) and pump ( ) techniques
during the 90 sec. of injection
Fig. 2
Correlation between the maximum venous
pressure achieved at the end of injection
and the lidocaine plasma level in the
Manual technique
Fig. 3
Correlation between the maximum
venous pressure achieved at the end
of injection and the lidocaine
plasma level in the pump technique
EVALUATION OF THE TOURNIQUET LEAK DURING FOREARM INTRAVENOUS REGIONAL ANESTHESIA
manual injection on the venous pressure during forearm
IVRA. However, El-Hassan et al12 had compared the
effect of different rates of infusion on the rate of rise
of venous pressure on one volunteer during simulated
Bier’s block. They reported that the slower the rate of
injection the lower was the venous pressure.
It has been suggested that, the occurrence of
convulsions during the performance of intravenous
regional analgesia with the tourniquet in situ may be
partly explained by the generation of exceptionally
high pressures in the venous system of the arm. The
pressures generated were greater than or equal to the
occluding pressure of the tourniquet. This in turn may
lead to flow of injectate under the tourniquet and into
the systemic circulation14-16.
In the present study, although non of the volunteer
in both techniques had a maximum venous pressure that
exceeded the inflation pressure, leak of lidocaine had
occurred in 11 out of 14 cases (78.5%) in the manual
technique, and 5 out of 14 cases (35.7%) in the pump
technique with a magnitude of 0.86 (0.5) µg.ml-1 and
0.32 (0.4) µg.ml-1 respectively. This in agreement with
Kalso et al13, and Chan et al5, who reported a lidocaine
leakage rate of 55% and 67% respectively.
More interestingly, the present study reported a
linear correlation between the magnitude of the leak
and the maximum venous pressure in both techniques.
The possible explanation is that, decrease in the
pressure gradient between the inflation pressure and the
275
venous pressure could exacerbate the unavoidable leak
through the interosseous vessels which are assumed to
be protected from the tourniquet pressure.
Limitations of this study consist of, First; this
trial would be strengthened if it used different rates
of injection as well as different levels of inflation
pressure, but this necessitated multiple sessions which
was refused by the volunteers. However; this could be
an idea for further study. Second; the present study did
not test the clinical efficacy of the performed block,
this is because the clinical efficacy of forearm IVRA
had been proven by many of previous studies5,17,19, as
well as for ethical reason as this study was done on
volunteers.
The present study concluded that the use of
pump injection for forearm IVRA could significantly
decrease the maximum venous pressure, and reduce
the incidence and the magnitude of lidocaine leak past
the tourniquet. This possibly will increase the duration
of the block and further decrease the incidence of
potential systemic toxicity.
Acknowledgements
I wish to thank all members of the Department of
Anaesthesia in King Fahad Hospital, Al-Kobar, Saudi
Arabia with special thanks to Dr. S. Abdulfatah, Dr. M.
Al-Tahhan, Dr. H. Mowafi and Mr. S. Abdulrahman,
for their help and support.
M.E.J. ANESTH 20 (2), 2009
276
References
1. Brown EM, McGriff JT, Malinowski RW: Intravenous regional
anaesthesia (Bier block): review of 20 years’ experience. Can J
Anaesth; 1989, 36:307-10.
2. Dunbar RW, Mazze RI: Intravenous regional anesthesia: experience
with 779 cases. Anesth Analg; 1967, 46:806-13.
3. Heathm: Deaths after intravenous regional anaesthesia. British
Medical Journal; 1982, 285:913-4.
4. Auroy Y, Narchi P, Messiah A, et al: Serious complications related
to regional anesthesia: results of a prospective survey in France.
5. Chan CS, Pun WK, Chan YM, Chow SP: Intranvenous regional
analgesia with a forearm tourniquet. Can J Anaesth; 1987, 34:21-5.
6. Rousso M, Drexler H, Vatashsky E, et al: Low i.v. regional
analgesia with bupivacaine for hand surgery. Br J Anaesth; 1981,
53:841-4.
7. Ng ES, Ting JR, Foo SL, Akram SA, Fadzlina AA, Alywiah JS,
Ahmad TS: The comparison of discomfort level between upper arm
and forearm tourniquet. Med J Malaysia; 2006, 61 Suppl B:23-6-8.
8. Cotev S, Robin GC: Experimental studies on intravenous regional
anaesthesia using radioactive lignocaine. Br J Anaesth; 1966,
38:936-9.
9. Coleman MM, Peng PW, Regan JM, et al: Quantitative Comparison
of Leakage Under the Tourniquet in Forearm Versus Conventional
Intravenous Regional Anesthesia. Anesth Analg; 1999, 89:1482-6.
10.Rosenberg PH, Kaw EA, Tuominen MK, Linden HB: Acute
bupivacaine toxicity as a result of venous leakage under the
tourniquet cuff during a Bier Block. Anesthesiology; 1983, 58:95-8.
11.Shaw JA, Murray DG: The relationship between tourniquet pressure
and underlying soft-tissue pressure in the thigh. J Bone Joint Surg;
1982, 64A:1148-52.
12.El-Hassan KM, Hutton P, Black AMS: Venous pressure and arm
volume changes during simulated Bier’s block. Anaesthesia; 1984,
39:229-35.
13.Kalso E, Tuominen M, Rosenberg PH, Alila A: Bupivacaine
blood levels after intravenous regional anaesthesia of the arm. Reg
Anaesth; 1982, 5:81-4.
14.Grice SC, Morell RC, Balestrieri FJ, et al: Intravenous regional
anesthesia: evaluation and prevention of leakage under the
tourniquet. Anesthesiology; 1986, 65:316-20.
15.Davies JA, Hal UD, Wilkey AD, Smith JE, Walford AJ, Kale VR:
Intravenous regional analgesia. The danger of the congested arm and
the value of occlusion pressure. Anaesthesia; 1984, 39:416-21.
16.Lawes EG, Johnson T, Pritchard P, Robbins P: Venous pressures
during simulated Bier’s block. Anaesthesia; 1984, 39:147-9.
17.Ploudre G, Barry PP, Tardif L, et al: Decreasing the toxic potential
of intravenous regional anaesthesia. Can J Anaesth; 1989, 36:498502.
18.Pun WK, Chow SP, Luk KDK, et al: Sequential forearm intravenous
regional and infiltration anaesthesia: value for haemostasis. J Hand
Surg Br; 1990, 15:115-7.
19.Khuri S, Uhi RL, Martino J, Whipple R: Clinical application of the
forearm tourniquet. J Hand Surg Am; 1994, 19:861-3.
TIME TO EXTUBATION IN INFANTS
UNDERGOING PYLOROMYOTOMY
- Isoflurane Inhalation vs Remifentanil Infusion -
Sonia Ben Khalifa, Sami Blidi, Mehdi Trifa,
Alia Skhiri, Mehdi Drira, Tarek Regaya
and A mjed F ekih H assen
**
Abstract
Background: Infantile hypertrophic pyloric stenosis (IHPS) associated with metabolic
alkalosis, could induce late anesthesia recovery, especially when opioids are used. The aim of this
study was to compare the time of extubation and the quality of perioperative analgesia in infants
scheduled for pyloromyotomy, receiving either isoflurane inhalation or remifentanil infusion.‎
Methods: Thirty full-term infants scheduled for pyloromyotomy were prospectively studied.
A standardized anesthetic induction was performed. For ‎maintenance of anesthesia, infants were
randomly allocated to receive either isoflurane 0.75% of ‎inspired concentration (GI n = 15),
or remifentanil as a continuous infusion of 0.4 μg.kg-1.mn-1 (GR n = 15). At the beginning of
skin closure, the anesthetic was discontinued and 15 mg.kg-1 of paracetamol administered. Non
parametric tests were used in statistical analysis.‎
Results: The time to ‎extubation was similar in both groups. The intraoperative heart rate was
significantly lower in t‎he GR group.‎
Conclusion: Remifentanil provided better intraoperative analgesia than ‎isoflurane in infants
undergoing pyloromyotomy without increasing time to extubation.
From Department of Anesthesia and Intensive Care, Children’s Hospital, Tunis.
Corresponding author: Dr. Mehdi Trifa, Dept. of Anesthesia and Intensive Care, Children’s Hospital, Bab Saadoun 1006,
Tunis, Tunisia. Tel: (00216) 99 323374, Fax: (00216) 71570932, E-mail: [email protected]
277
M.E.J. ANESTH 20 (2), 2009
278
Sonia Ben Khalifa ET. AL
Introduction
value, was treated with atropine 20 µg.kg-1.
Infantile hypertrophic pyloric stenosis (IHPS)
is one of the most common infant gastrointestinal
disorders requiring surgery. Pyloric outlet obstruction
causes projectile vomiting thus inducing electrolyte
and metabolic disturbances. The classic abnormality is
a hypochloremic metabolic alkalosis that could induce
late anesthesia recovery, especially when opioids are
used1. Therefore, inhalational agents are usually used
as maintenance anesthetics.
At the beginning of skin closure, the anesthetic
maintenance was discontinued and intravenous
paracetamol 15 mg.kg-1 was administered. Extubation
was performed when infant was awake, had regained
his airway reflexes and was adequately warmed.
The aim of the present study was to compare time
to extubation and quality of perioperative analgesia
with the use of remifentanil infusion and compare it to
that of isoflurane inhalation, in infants scheduled for
pyloromyotomy.
Following the Ethics Committee’s approval and
written parent’s informed consent, thirty ASA I or II
full term infants (gestational age ≥37 weeks) admitted
for IHPS, were prospectively included in a randomised
single-blind study. They underwent pyloromyotomy
after normalization of their metabolic and electrolyte
imbalance (serum bicarbonate ≤30 mmol.L-1, serum
sodium ≥130 mmol.L-1). Infants who presented difficult
intubation were excluded from the study.
Infants were not premedicated. Induction was
performed with propofol 5 mg.kg-1 and succinylcholine
2 mg.kg-1. For maintenance, infants were allocated,
using a random-number table, to receive nitrous oxide
and oxygen (50%50%), with either isoflurane at 0.75%
inspired concentration (GI n = 15), or remifentanil as a
continuous infusion at 0.4 µg.kg-1.mn-1 (GR n = 15).
If signs of light anesthesia appeared (movement,
increases in systolic arterial blood pressure (SABP)
and/or in heart rate (HR) 20% above basal values), the
inspired concentration of isoflurane and the infusion
rate of remifentanil were increased by respective
increments of 0.25% (GI) and 0.05 µg.kg-1.mn-1 (GR)
until a maximum infusion rate of 2 µg.kg-1.mn-1 (GR)
was reached. In infants who developed hypotension
(decreases in SABP 20% of basal value), the inspired
concentration of isoflurane and the infusion rate of
remifentanil were respectively decreased by 0.25%
(GI) and 0.05 µg.kg-1.mn-1 (GR). Bradycardia, defined
as a decrease of the HR 30% compared to the previous
In the PACU, the BP, HR and PSO2 were
monitored. The postoperative pain was assessed by
Amiel-Tison score, which is a behavioral approach
using facial expressions, body movements, intensity
and quality of crying as indices of reponse to
nociceptive stimuli2. If the score was higher than 7,
nalbuphine 0.2 mg.kg µg-1 was administered by i.v.
route.
The following data were collected: demographics,
time to extubation, duration of surgery, intraoperative
HR and SABP at induction, after intubation, at the skin
incision, and then at five-minute intervals until the end
of surgery. Postoperatively, the Amiel-Tison score was
recorded every 20 min. after extubation for 2 hours,
Occurrence of intraoperative incidents (movement at
incision, bradycardia) were noted.
Data were analysed using package SPSS 13.0.
Statistical analysis involved Chi-square and MannWhitney tests. P values ≤0.05 were considered
statistically significant.
Results
No statistical difference was noted between the
two groups with regard to demographics, duration of
surgery and basic hemodynamic values (Table 1).
Table 1
Patient characteristics and intraoperative data among infants
anesthetized for pyloromyotomy
GI
GR
p
Age (days)
43 ± 12
37 ± 14
0.12
Weight (Kg)
3.85 ± 1
3.51 ± 0.5
0,13
5
5
1
33 ± 9
31 ± 9
0.70
Basic HR (beats
per minute)
148 ± 18
137 ± 19
0.06
Basic SABP
(mmHg)
88 ± 12
84 ±15
0.39
Sex-ratio
Duration of
surgery (min.)
Data are mean ± SD except for sex-ratio of patients. No significant
difference (p >0.05) was found between the two groups
TIME TO EXTUBATION IN INFANTS UNDERGOING PYLOROMYOTOMY: REMIFENTANIL VERSUS
ISOFLURANE
On admission, biochemical findings showed
metabolic alkalosis (serum bicarbonate ≥30 mmol.L-1
in 7 cases), hypokalemia (serum potassium ≤3.7,
in 3 patients) and hyperkalemia (serum potassium
≥4.8 mmol.L-1 in 3 other infants). After preoperative
correction, serum bicarbonate and natremia were
similar in the two groups (Table 2).
Table 2
Preoperative biochemical findings among infants scheduled for
pyloromyotomy
Serum bicarbonate
(mmol.L-1)
Natremia (mmol.L-1)
GI
GR
p
24 ± 2
24 ± 5
0.62
135 ± 3
134 ± 3
0.34
Data are mean ± SD. No significant difference (p >0.05) was found
between the two groups
Time to extubation was similar between the two
groups: 17 ± 10 min (GI) and 20 ± 11 (GR), p = 0.42.
The intraoperative HR was lower in GR compared to
GI group:
At skin incision
5 min.
10 min.
GR
GI
118
119
122
135 p = 0.01
132 p = 0.022
133 p = 0.049
Intraoperative tachycardia requiring increases of
the inspired concentration of isoflurane occurred in one
patient of GI. No statistical difference could be found
between the groups regarding intraoperative SABP.
The use of remifentanil, a short-acting opioid,
provides analgesia during pylorotomy without
increasing time to extubation, meanwhile, narcosis is
ensured by propofol and N2O/O2 mixture. The openlabel study comparing halothane to remifentanil in
infants who underwent pylorotomy, inspired our trial4.
In our study, we chose isoflurane instead
of halothane. The time to tracheal extubation as
comparable in both groups: 16.8 ± 10.2 in GI group
versus 19.6 ± 10.6 in GR group (p = 0.47). A similar
result was found in Davis’ study4 (7.7 ± 3.2 versus 7.4
± 6.3). A retrospective cohort study showed a shorter
time to discharge from the OR when remifentanil was
used as maintenance anesthetic with propofol (12.5
± 10.6 min), compared to isoflurane (14.2 ± 7.8),
sevoflurane (18.5 ± 11.7) and halothane (24.8 ± 11.1)
(p<0.01)5.
Intraoperative analgesia was assessed by SABP
and HR variation during surgery and movement at
surgical incision. Intraoperative HR was significantly
lower in GR group when compared to the GI group
at skin incision, and after 5 and 10 minutes, showing
a better analgesia for the remifentanil-anesthetized
infants (Fig. 1). Davis et al did not find differences
between the two groups regarding intraoperative
hemodynamic parameters4. In our study, movement at
skin incision was observed in 3 infants of each group
and required deepening of anesthesia.
Fig. 1
Intraoperative heart rate (HR) among infants
scheduled for pyloromyotomy: comparison between
remifentanil (GR) and isoflurane (GI). HR was lower
in GR compared to GI at skin incision (p = 0.01), 5 (p
= 0.022) and 10 minutes after (p = 0.049)
There was no significant difference between the
groups with regard to postoperative Amiel-Tison score,
HR and SABP.
At skin incision, movement was recorded in
3infants in each group. Three patients in GT group had
developed episodes of bradycardia, but with favourable
progress.
279
200
*
180
Discussion
In view of its metabolic disorders, there is no
ideal anesthetic technique for the care of IHPS: the
use only of inhalational agents for the maintenance
of anesthesia neglects intraoperative analgesia,
while the administration of opioids could induce late
anesthesia recovery due to persistent cerebrospinal
fluid alkalosis3.
beats per minute
*
160
*
140
*p<0,05
120
100
GI
80
GR
before induction
Incision (I)
before skin incision
I + 10 min
I + 5 min
I + 20 min
I + 15 min
M.E.J. ANESTH 20 (2), 2009
280
Postoperative pain, as assessed by the AmielTison score, was higher in GR, but without any
significant difference. No infant of the two groups
required supplementary analgesic during the two
postoperative hours. Davis et al, had found a similar
result in the postoperative period comparing halothane
to remifentanil, in infants undergoing pylorotomy4,
while children who received remifentanil had
worse postoperative pain scores in other kinds of
surgery. The comparison of remifentanil to fentanyl
in tonsillectomy and adenoidectomy in pediatric
ambulatory surgery, found higher postoperative pain
scores in the remifentanil than in the fentanyl groups6.
After elective strabismus surgery, pain scores were also
higher in the remifentanil group, compared to children
who received alfentanil, propofol or isoflurane7.
During SHP, the alkaline pH of the cerebrospinal fluid
could induce analgesic effect, explaining the absence
of increase in the postoperative pains cores following
pyloromyotomy.
Bradycardia occurred in 3 infants in GR group,
whereas hypotension occurred in one patient in each
group. The occurrence of bradycardia in the GR
patients could be related to the flow of remifentanil
Sonia Ben Khalifa ET. AL
and the lack of administration of atropine at induction
in our infants8,9. In the study comparing halothane with
remifentanil, no infant developed bradycardia, but a
tendency to hypotension was noted in the halothane
group, yet without any significant difference (p =
0.08)4.
No postoperative respiratory complication
was found among our infants. In Davis’ study4, only
children belonging to halothane group had developed
episodes of postoperative apnea. The incidence of
postoperative apnea and hypoxia was similar with
remifentanil compared to propofol and isoflurane, but
lower than with alfentanil7.
Conclusion
Remifentanil in association with an N2O/O2
mixture provided better intraoperative analgesia than
did isoflurane, thus providing proper narcosis and a
comparable time to extubation. Quality of postoperative
analgesia was similar in both groups. Therefore,
a remifentanil-based anesthesia is an interesting
alternative to the inhaled anesthetic technique of
isoflurane, for IHPS.
References
1. MacDonald NJ, Fitzpatrick GJ, Moore KP, Wren WS, Keenan M:
Anaesthesia for congenital hypertrophic pyloric stenosis. A review
of 350 patients. Br J Anaesth; 1987, 59:672-7.
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ambulatory care of children aged 1 month to 15 years. Text of the
recommendations of the National Agency for Health Accreditation
and Evaluation. Arch Pediatr; 2001, 8:420-32.
3. Andropoulos DB, Heard MB, Johnson KL, Clarke JT, Rowe RW:
Postanesthetic apnoea in full-term infants after pyloromyotomy.
4. Davis PJ, Galinkin J, McGowan FX, Lynn AM, Yaster M, Rabb
MF, Krane EJ, Kurth CD, Blum RH, Maxwell L, Orr R, Szmuk
P, Hechtman D, Edwards S, Henson LG. A randomized multicenter
study of remifentanil compared with halothane in neonates and
infants undergoing pyloromyotomy. I. Emergence and recovery
profiles. Anesth Analg; 2001, 93:1380-6.
5. Sedeek K, Lavoie J. Anesthesia for hypertrophic pyloric stenosis: a
five-year review. Can J Anaesth; 2005, 52:A97.
6. Davis PJ, Finkel JC, Orr RJ, Fazi L, Mulroy JJ, Woelfel SK,
Hannallah RS, Lynn AM, Kurth CD, Moro M, Henson LG,
Goodman DK, Decker MD: A randomised, double-blinded study of
remifentanil versus fentanyl for tonsillectomy and adenoidectomy
surgery in pediatric ambulatory surgical patients. Anesth Analg;
2000, 90:863-71.
7. Davis PJ, Lerman J, Suresh S, McGowan FX, Coté CJ, Landsman
I, Henson LG: A randomised multicenter study of remifentanil
compared with alfentanil, isoflurane, or propofol in anesthetized
pediatric patients undergoing elective strabismus surgery. Anesth
Analg; 1997, 84:982-9.
8. Chanavaz C, Tirel O, Wodey E, Bansard JY, Senhadji L, Robert
JC, Ecoffey C: Haemodynamic effects of remifentanil in children
with and without intravenous atropine. An echocardiographic study.
Br J Anaesth; 2005, 94:74-9.
9. Tirel O, Chanavaz C, Bansard JY, Carré F, Ecoffey C, Senhadji L,
Wodey E. Effect of remifentanil with and without atropine on heart
rate variability and RR interval in children. Anaesthesia; 2005,
60:982-9.
Case Reports
ANESTHETIC IMPLICATIONS OF ACUTE
METHYLENEDIOXYMETHAMPHETAMINE
INTOXICATION IN A PATIENT WITH TRAUMATIC
INTRACEREBRAL HEMORRHAGE
- Case Report-
Samuel DeMaria Jr*, Ethan O Bryson**, And
Elizabeth A.M. Frost***
Abstract
The use of the street drug methylenedioxymethamphetamine (MDMA), commonly referred
to as ecstasy, has become increasingly prevalent amongst teenagers and young adults in the United
States and many other parts of the world. While most anesthesiologists are facile with the intricacies
of managing patients intoxicated by alcohol, cocaine and narcotics the new “club” drugs present
a challenge, especially under emergency conditions. MDMA, in particular, is the most commonly
abused club drug and potentially one of the most dangerous in the perioperative period. We present
a case report of traumatic subarachnoid hemorrhage in a patient with acute MDMA intoxication
and a review of the anesthetic implications.
Case
A 19-year-old man with an unknown medical and surgical history presented to the Emergency
Department after a motor vehicle collision in which he was the unrestrained driver. The patient
presented initially with a Glasgow Coma Score (GCS) of 9 and was emergently intubated in the
field. A passenger in the vehicle stated the patient was at a “rave” before the accident. He did not
know whether the patient took any illicit substances but stated that there was “X” at the party.
The patient was of average height and weight. Initial vital signs upon arrival to the Emergency
Department included heart rate 115 beats per minute, blood pressure 157/88 mmHg, respiratory
rate 12 breaths per minute, and O2 saturation 99% on FiO2 0.4 via mechanical ventilator. Rectal
temperature was 38.2°C. He had numerous facial abrasions but no open lacerations or obvious
fractures. Neurologic examination did not reveal any focal deficits and the patient was moving
all four limbs spontaneously. His lungs were clear and his cardiovascular exam was remarkable
only for tachycardia. Laboratory evaluation indicated sodium of 124 meq/L. Cerebral computed
tomography revealed a left-sided intracerebral hematoma and blood in the fourth ventricle with
slight midline shift.
From Department of Anesthesiology, Mount Sinai Medical Center, N.Y., N.Y., USA.
*
MD, Resident.
** MD, Assistant Professor.
*** MD, Professor.
Corresponding author: Dr. Elizabeth A.M. Frost, Department of Anesthesiology, Mount Sinai Medical Center, N.Y., N.Y.,
USA, One Gustave L Levy Place, New York, NY 10029. Tel: (212) 241-9240, Fax: (212) 876-3906.
281
M.E.J. ANESTH 20 (2), 2009
282
The patient was transported to the operating room
for emergent evacuation of the hematoma. A 20 gauge
intra-arterial catheter was placed in his left radial artery
prior to induction. Tachycardia persisted. Anesthesia
was induced with propofol 140 mg, fentanyl 100 mcg
and rocuronium 50 mg. The hemodynamic status
remained stable during the induction period. A bladder
temperature probe was placed and a temperature of
38.4°C was recorded. A forced air blanket set to ambient
air (24°C) was applied and cold normal saline hydration
with 1.5 liters and sodium chloride 3% (500 ml) was
administered during the four hour case. The patient
received an infusion of remifentanil (0.05-0.1 mcg/
kg/hr) and propofol (75-125 mcg/kg/min) throughout
the case as well as a low concentration of isoflurane
(0.5%) in oxygen and air. Electrolyte sampling prior to
closure showed a sodium of 133 meq/L. Temperature
prior to transport to the ICU was 36.4°C, heart rate 87
beats per minute and blood pressure 138/89 mmHg.
Sedation was continued for 24 hours and his trachea
was extubated 2 days later.
Following surgery, he had right-sided weakness
that improved over the next week. Three weeks after
the event, neurological examination was normal. He
was discharged home without neurologic sequelae.
Samuel DeMaria Jr ET. AL
Ecstasy is a hallucinogenic amphetamine analog
known amongst recreational drug users as XTC, X,
E and Adam. The drug is classified as a club drug
along with GHB (gamma hydroxybutyrate), ketamine
and flunitrazepam because of its use predominantly
at dance parties (“raves”) and dance clubs. MDMA
was patented in 1914 by Merck Pharmaceuticals as an
appetite suppressant. Given its purported entactogenic
effects (i.e., feelings of enhanced communication
with and closeness to others), it was promoted as a
psychotherapy adjunct in the 1970’s. Despite this
potential clinical use, abuse of MDMA prompted the
Drug Enforcement Administration (DEA) to issue a
schedule 1 drug classification in 1985. Since that time,
MDMA abuse in the US has steadily climbed.
MDMA is most often abused orally as a small
pill or capsule. As it is produced illegally, the purity
of street MDMA is highly variable, with numerous
compounds commonly mixed into the final product.
Indeed, the concentration of MDMA itself may vary
and accidental overdoses are likely. Any acute MDMA
intoxication should be approached as polysubstance
intoxication.
While alcohol, cocaine/amphetamine and opiate
use occasionally complicate the perioperative period,
the rise of designer and club drugs demands a new
paradigm in anesthetic management. The club drug,
ecstasy (methylenedioxymethamphetamine, MDMA)
has effects that may confuse the diagnosis, especially
in the head injured patient.
MDMA closely resembles the hallucinogen
mescaline and the stimulant amphetamine. These
structural relationships are predictive of its effects.
MDMA increases the release and decreases the reuptake
of serotonin and dopamine and may also have direct
agonist properties at serotonergic and dopaminergic
receptors as well as monoamine oxidase (MAO)
inhibitor effects. In vitro studies suggest an indirect
agonist effect on norepinephrine release5. Effects may
be felt within 20 minutes of ingestion and can last up
to 8 hours.
In the US, there were an estimated 19.7 million
people (or about 8.1 percent) over the age 12 using
illicit drugs in 2005. About 500,000 of these had taken
MDMA at least once during the year prior to being
surveyed1. According to the Texas Commission on
Alcohol and Drug Abuse people attending “raves”,
where ecstasy is prevalent, range in age 13 to 40
years2. MDMA is available at 70% of these gatherings
according to one study3. A 2001-2002 survey in Chicago
showed that roughly 40% of 18-40 year olds had gone
to a “rave” and roughly half of these participants had
taken a club drug4.
The drug is metabolized principally through
the cytochrome P450 (CYP450) 2D6 enzyme. Phase
II metabolism of MDMA is poorly understood. One
metabolite has been shown to be a 2D6 inhibitor
in vitro. 2D6 inhibitors (e.g., cocaine, methadone,
haloperidol, fluoxetine, paroxetine) block the main
Discussion
Effects include heightened alertness, “closeness”
to others, increased emotional lability, decreased
aggression and increased sexual arousal. Hypertension,
tachycardia and hyperpyrexia are common. Mydriasis,
bruxism, sweating and agitation with later lethargy,
fatigue, anorexia and depressed mood follow.
ANESTHETIC IMPLICATIONS OF ACUTE METHYLENEDIOXYMETHAMPHETAMINE INTOXICATION IN A
PATIENT WITH TRAUMATIC INTRACEREBRAL HEMORRHAGE
metabolic pathway of MDMA and may substantially
increase the effects. Benzodiazepines are metabolized
principally by the 3A4 enzyme and likely have limited
metabolic interaction with MDMA. Pro-serotonergic
drugs (e.g., fluoxetine, amphetamines, St. John’s
wort, tramadol, lithium,) may increase the severity of
MDMA’s pro-serotonin effects.
Hyperthermia is the most common adverse effect
and a leading cause of MDMA-related mortality. The
mechanism relates most likely to serotonergic effects in
the hypothalamic thermoregulatory center compounded
by sustained muscle hyperactivity from long periods of
dancing in a warm environment (e.g., club), increased
metabolic rate and rigidity. In genetically susceptible
pigs, MDMA has been identified as a trigger of
malignant hyperthermia (MH). Hyperpyrexia leading
to rhabdomyolysis, disseminated intravascular
coagulation (DIC) and multi-organ failure is the
most dreaded consequence6. Increased temperature
increases cerebral blood flow and intracranial pressure
and could worsen head trauma. Also, hyperthermia
is not uncommon after head injury which will thus
compound the differential diagnosis.
Sympathetic
stimulation
from
MDMA
intoxication increases myocardial oxygen demand and
causes tachycardia, vasoconstriction, hypertension
and occasionally acute myocardial infarction and
dilated cardiomyopathy if prolonged. Cerebral
autoregulation may fail, allowing dangerous increases
in cerebral blood flow. Significant hypotension and
low cardiac output may be encountered after the initial
hyperdynamic state due to catecholamine depletion or
autonomic dysregulation.
Electrolyte disturbances in MDMA abusers are
particularly dangerous. Hyponatremia which often
results from excessive water intake from increased
physical activity (i.e., dancing at parties where MDMA
is present) has been associated with MDMA-related
seizures, stupor and incontinence7. Increases in plasma
ADH levels can be induced by MDMA use which may
compound the increased intake of water by users8.
The occurrence of severe hyponatremia is an unusual
complication in young patients with mild head injuries.
One retrospective review of patients in a Thai hospital
demonstrated that of over one thousand mild head
injuries reviewed, only three patients demonstrated
283
severe hyponatremia. All three of these patients were
found to have recently ingested MDMA9.
Other effects attributed to acute MDMA
intoxication include hepatotoxicity with hepatonecrosis
and fulminant liver failure, pneumothorax and
pneumomediastinum, acute renal failure from
rhabdomyolysis
and
creatine
phosphokinase
elevations lasting up to 4 days after hospitalization.
Cerebrovascular events like subarachnoid hemorrhage,
cerebral infarct and venous sinus thrombosis are
relatively uncommon.
Most toxicology screens will not detect MDMA
and its metabolites and a history is vital although often
not available. A directed physical exam is also critical,
with particular attention directed to vital signs (with
suspicion heightened if patient is hyperthermic) and
cardiopulmonary findings. Initial studies that may help
the anesthesiologist’s approach are mostly nonspecific
tests such as the electrocardiogram and electrolytes.
Succinylcholine should be used cautiously given
the risk of compounding the malignant hyperthermialike effects of the drug, raising intracranial pressure or
potentially worsening hyperkalemia, if present. Also,
the bruxism often associated with ecstasy may make
intubation more challenging in spite of patient habitus.
If the patient is conscious and capable of protecting his
or her airway, anxiolysis with midazolam or diazepam
may be useful and also raises seizure threshold.
Management of hyperthermia, cardiovascular
instability, electrolyte derangements and renal and
hepatic dysfunction are imperative. Wide swings in
hemodynamic parameters are to be avoided given these
patients’ higher risk of cardiomyopathy and coronary
or cerebral vasospastic events. An intra-arterial
blood pressure monitor, placed prior to induction, is
advised.
Propofol and thiopental are appropriate induction
agents as ketamine may induce catecholamine release
from potentially exhausted stores. Etomidate tends to
have stable hemodynamic effects but may increase
seizure activity, which may be attenuated by preinduction benzodiazepines. Paralysis with a nondepolarizing agent immediately slows heat production
and help lower body temperature. Also, unlike
succinylcholine, non-depolarizers are not associated
with malignant hyperthermia. For this reason,
M.E.J. ANESTH 20 (2), 2009
284
rocuronium may be ideally situated to both initiate
a rapid sequence induction and maintain paralysis.
Severe hypertension and raised intracranial pressure
may occur during direct laryngoscopy and commonly
used methods to blunt this response (e.g., intravenous
lidocaine, opioids) are correct.
Maintenance of anesthesia for head trauma is
generally with volatile anesthetics. However, volatile
gases are known triggers of malignant hyperthermia
and are best used conservatively if a patient has ingested
MDMA. A narcotic infusion with remifentanil, which
is metabolized by blood and tissue esterases, serves
the dual role of blunting sympathetic output and
lowering the amount of gaseous anesthetic necessary
for surgery. Other narcotics, such as fentanyl, are also
suitable. Serial sodium measurements and appropriate
correction are important.
Potential intraoperative pitfalls are many.
Intraoperative hypertension and tachycardia should be
treated with labetalol, with its alpha and beta blocking
effects. Pure beta blockade worsens hypertension by
tipping the balance of catecholamine action to alpha-1
receptors. Intraoperative hypotension requires rapid
infusion of crystalloid or the use of direct alpha-1
agonists. Avoiding indirect agonists such as ephedrine
prevents the theoretical catastrophe generated when
an already exhausted sympathetic nervous system is
prompted to release catecholamines.
Samuel DeMaria Jr ET. AL
Hyperthermia must be treated promptly to
avoid rhabdomyolysis and DIC. Basic measures
include cold fluids, active cooling with ice packs and
avoidance of warming blankets. Given the presumed
central mechanism of MDMA-induced hyperthermia,
dantrolene use is controversial as the drug inhibits
the release of calcium from sarcoplasmic reticulum.
Dantrolene may help exertional heat stroke which
may be similar to MDMA-induced hyperthermia.
Hall and Henry noted that during hyperthermia, the
calcium levels required for excitation-contraction
coupling are reduced such that hyperthermia alone
can cause contraction and subsequent heat production
and increased metabolic demand10. They suggested
that dantrolene, which raises the calcium requirements
for excitation-contraction coupling, may be of some
benefit even if it does not directly counteract central
causes of hyperthermia.
In summary, patients acutely intoxicated by
ecstasy may be hyperthermic, hyperdynamic and have
many other dangerous complications. Neurological
sequelae, in particular, present a challenge in terms
of evaluation and treatment of the patient. We present
a case of traumatic intracranial hemorrhage possibly
worsened by concurrent ecstasy abuse. A conservative
approach to such patients using thorough preoperative
assessment, a gentle anesthetic induction and
appropriate monitoring is crucial to a good outcome.
References
1. US Department of Heath and Human Services. National Survey on
Drug Use and Health. Washington DC: US Department of Health
and Human Services, 2005.
2. Kotarba JA: Research Briefs. The Rave Scene in Houston Texas. An
Ethnographic Analysis. Austin, Tex. Texas Commission on Alcohol
and Drug Abuse, October 1993.
3. National Institute on Drug Abuse. The Monitoring the Future
national results on adolescent drug use: overview of key findings,
2001. Ann Arbor, Mich: University of Michigan Institute for Social
Research, 2002.
4. Fendrich M, Wislar JS, Johnson TP, Hubbell A: A contextual
profile of club drug use among adults in Chicago. Addiction; 2003,
98:1693-1703.
5. Smith KM, Larive LL, Romanelli F: Club drugs:
methylenedioxymethamphetamine,
flunitrazepam,
ketamine
hydrochloride, and gamma-hydroxybutyrate. Am J Health Syst
Pharm; 2002 Jun 1, 59(11):1067-76.
6. Gill JR, Hayes JA, De Souza IS, et al: Ecstasy (MDMA) deaths in
New York City: a case series and review of the literature. J Forensic
Sci; 2002, 47:121-126.
7. Mallick A, Bodenham AR: MDMA-induced hyperthermia: a
survivor with an initial body temperature of 42.9°C. J Accid Emerg
Med; 1997, 14:336-338.
8. Henry JA, Fallon JK, Kicman AT: Low-dose MDMA (“Ecstasy”)
induces vasopressin secretion [letter]. Lancet; 1998, 351:1784.
9. Rukskul P: Ecstasy (MDMA) ingestion related with severe
hyponatremia in patients with mild head injury. J Med Assoc Thai;
2005 Jan, 88(1):41-4.
10. Hall AP, Henry JA: Acute toxic effects of ‘Ecstasy’ (MDMA)
and related compounds: overview of pathophysiology and clinical
management. British Journal of Anaesthesia; 2006, 96(6):678-685.
HUMAN POISONING AFTER INGESTION
OF PUFFER FISH CAUGHT
FROM MEDITERRANEAN SEA
- A Case Report -
Suheil Chucrallah Chamandi*, Kamal Kallab**,
Hanna Mattar*** and Elie Nader****
Abstract
Puffer fish poisoning is due to a powerful neurotoxin produced by bacteria living in this kind
of fish. Though the sea of Lebanon (Mediterranean) is not endemic of puffer fish and incidence of
its serious poisoning is rare, yet occasional incidences do occur. The purpose of this presentation is
to raise the awareness of fishermen, fish-restaurant frequenters, public health organizations and the
Ministry of Health ,of its serious symptomology and to seek medical help as soon as possible.
Case Report
A 68 year-old woman, with hypertension and diabetes, was brought to the Emergency
Department of the Hopital Universitaire de Notre Dame De Secours, in January 2008 complaining
of proximal limb weakness and dyspnea.
Four hours prior to her arrival, the patient had eaten a half-cooked fish liver. Three hours and
thirty minutes later, she started feeling a tingling sensation in the perioral region and in the tip of
her fingers associated with blurred vision, head heaviness, nausea and one episode of vomiting.
Ten minutes later, she lost her ability to hold her head up and had developed weakness of
her upper and lower extremities. This was accompanied by mild abdominal distention and urinary
urgency. The patient then developed quadriplegia, hypophonia and dysarthria. She complained
of dyspnea, ophtalmoplegia and had an absent gag reflex. Subsequently, the patient underwent
endotracheal intubation.
After intubation, the neurological examination revealed normal consciousness and orientation,
bilateral third, fourth and sixth nerve palsies, normal pupillary reflexes, absent gag and cough
reflexes and the deep tendon reflexes. Computed Tomography (CT) scan of the brain did not show
any abnormalities.
Upon further questioning on the following day, the family reported that the fish was a blowfish
and identified it by picture comparisons, as Lagocephalus scleratus (Fig.1 & 2).
Affiliation to Holy Spirit University – USEK – Medical School-Kaslik, Lebanon and Lebanese University.
*
MD, IC and Pain Clinic Director, Lebanese University-Medical Faculty-Beirut, Lebanon.
** MD, Dean of Medical Faculty.
*** MD,
Affiliation to Lebanese University Medical School-Beirut, Lebanon.
****MD.
Corresponding author: Dr. Souheil C Chamandi, Holy Spirit University – USEK – Medical School, Kaslik, Lebanon.
Phone: +961 3 230071, Fax: 009619944099, E-mail: [email protected]
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M.E.J. ANESTH 20 (2), 2009
286
Suheil Chucrallah Chamandi ET. AL
Four days later she was extubated and recovered
fully without any neurological sequelae.
Fig. 1
Dr. S. Chamandi holding a Puffer fish caught from our sea
Between 1974-1983, the incidence of puffer fish
intoxication was estimated to be as high as 200 cases
per year, with mortality approaching 50%. Puffer fish
poisoning is most commonly seen in Japan. Sporadic
cases have been reported in the United States.
The different bacteria living in puffer fish
liver, gonads, intestines and skin, are known to
synthesize a very potent heat stable neurotoxin called
“tetrodotoxin”.
Fig. 2
Puffer fish caught in the Mediterranean sea
Historically, the first recorded cases of
tetrodotoxin poisoning were from the logs of Captain
James Cook, the British explorer, navigator and
cartographer during his voyages to the Pacific Ocean,
late part of the 18th century. He recorded that his crew
were eating some local tropic fish (puffer fish), and
feeding the remains to the pigs kept on board. The crew
experienced numbness and shortness of breath, while
the pigs were all found dead the next morning. It is
clear that the crew received a mild dose of tetrodotoxin,
while the pigs ate the puffer fish body parts that
contained most of the toxin, thus killing them.
The toxin was first isolated and named in 1909
by Japanese scientist Yoshizumi Tahara: Tetrodotoxin
(anhydrotetrodotoxin 4-epitetrodotoxin, tetrodonic
acid, TTX) (Fig. 3 & 4).
Fig. 3
Discussion
Puffer fish is the general name for fish of the
family Tetraodontidae, class Osteichthyes order
Tetraodontiformes. The Lagocephalus scleratus is
known to be one of the most dangerous puffer fish
species. These fish can swell their bellies to a shape
resembling a ball. They are geographically distributed
in waters surrouding Japan, the Indian and South
Pacific Oceans and North American waters (lesser
degree). The Mediterranean coasts is not known as an
endemic region.
Fig. 4
Poisoning from tetrodotoxin is of particular
public health concern in Japan. “Fugu” is a traditional
delicacy, prepared and sold in special restaurants where
trained and licensed chefs carefully remove the viscera
to reduce the danger of poisoning.
Pathophysiology
The toxin blocks the action potentials in nerves by
binding to the pores of the voltage-gated, fast sodium
channels in nerve cell membranes. Tetrodotoxin binds
HUMAN POISONING AFTER INGESTION OF PUFFER FISH CAUGHT FROM MEDITERRANEAN SEA
to what is known as site 1 of the fast voltage-gated
sodium channel that is located at the extracellular
pore opening of the ion channel. The binding of any
molecules to this site, will temporarily disable the
function of the ion channel. Saxitoxin and several of
the conotoxins, also bind the same site.
The toxin blocks the fast Na+ current in human
myocytes (the contractile cells of the muscles), thereby
inhibiting their contraction. By contrast, the sodium
channels in pacemaker cells of the heart are of the slow
variety, so action potentials in the cardiac nodes are not
inhibited by the compound. The poisoned individual,
therefore dies not because the electrical activity of the
heart is compromised, but because the muscles are
effectively paralyzed. It is to noted that blocking of
fast Na+ channels has medicinal use in treating some
cardiac arrhythmias. Tetrodotoxin has also proved
useful in the treatment of pain (originally used in Japan
in the 1930’s), in such diverse problems as terminal
cancer, migraines and heroin withdrawal.
Clinical Picture
The clinical manifestations typically develop
within 30 min. of ingestion, but may be delayed by
up to 4 hours. Death has occurred within 17 min. of
ingestion. Usually, paresthesias of the lips and tongue
is followed by several signs as simple as sweating
to life threatening, such as severe hypotension,
respiratory failure, cardiac arrythmias and even coma
(Table 1).
Table 1
Signs & symptoms of puffer fish poisoning
287
Tetrodotoxin intoxication is divided into four
stages based on neurologic signs:
1 – Rapidly after ingestion (10 min to 2 hours)
numbness and/or paresthesias of the lips
and tongue and often of fingers occur.
2 – Sensory symptoms progress markedly.
3 – Muscular paralysis of extremities occur.
Motor incoordination progresses and
paralysis develops, but consciousness is
maintained. Voice production is difficult
because of bulbar muscle paralysis.
4 – Consciousness
may
progressively
deteriorate and respiratory paralysis can
cause death.
Our patient had eaten the liver of Lagocephalus
scleratus, known to be one of the most dangerous fish
species. The different bacteria living in puffer fish liver,
gonads, intestines and skin, are known to synthesize a
very potent heat stable neurotoxin “tetrodotoxin”. The
diagnosis was made on the clinical manifestations and
the recent dietary history. The onset of symptoms in
our patient was more delayed than usual. Although she
reached the third stage, she remained hemodynamically
stable. Her consciousness was intact during all the
paralytic period, and she returned to her baseline status
over a short period. Even though the tetrodotoxin level
was not determined in serum or urine, the clinical
history, the progressive recovery and the kind of fish
eaten (confirmed later by presenting the rest of the fish
ingested by the patient), were all consistent with the
diagnosis of puffer fish poisoning.
l sialorrhea
l sweating
l headache
l weakness
Conclusion
l lethargy
l ataxia incoordination
l tremor
l paralysis
l cyanosis
l aphonia
l dysphagia
l seizures
l dyspnea
l bronchorrhea
l bronchospasm
l respiratory failure
Since Puffer fish is not endemic in the shores
of Lebanon, its poisoning is considered rare and
potentially dangerous. Nevertheless with the increasing
tourism and foreign fish importation, puffer fish
poisoning may occur in Lebanon. The purpose of this
presentation is to raise the awareness of this poisoning
among fish eaters and to coerce the Ministry of Health
to take the necessary actions towards the fishermen,
the restaurants and educate the public, in order to avoid
the ingestion of this kind of fish, to recognize it signs
of poisoning, and in case of accidental ingestion to
seek medical help as soon as possible.
l coma, hypotension l gastroenteric symptoms are
often severe and include nausea,
vomiting…
l diarrhea, and
abdominal pain.
l cardiac arrhythmias may precede
complete respiratory failure and
cardiovascular collapse
M.E.J. ANESTH 20 (2), 2009
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Suheil Chucrallah Chamandi ET. AL
Recommended readings
1. Field J: Puffer Fish Poisoning. Journal of Accident & Emergency
Medicine; Sep 1998, 15:(5) 334-336.
2. Lin SJ, Chai TJ, Jeng SS, Hwang DF: Toxicity of the puffer Takifugu
rubripes cultured in northern Taiwan. Fisheries Science; Oct 1998,
64:(5) 766-770.
3. Malpezzi ELA, deFreitas JC, Rantin FT: Occurrence of toxins,
other than paralyzing type, in the skin of Tetraodontiformes fish.
Toxicon; Jan 1997, 35:(1) 57-65.
4. Centers for Disease Control and Prevention: Tetrodotoxin poisoning
associated with eating puffer fish transported from Japan California,
1996. MMWR Morb Mort Wkly Rep; 1996; 45:389.
5. Watters MR: Organic neurotoxins in sea foods. Clin Neurol
Neurosurg; 1995; 97:119.
6. Neurologic illness associated with eating Florida puffer fish, 2002.
MMWR Morb Mortal Wkly Rep; 2002; 51:321.
7. Kenichiro Oda, Kazukuni Arak, Tadahide Totoki, Hiroshi
Shibasaki: Nerve conduction study of human tetrodotoxication.
Neurology; 1989, 39.
8. Yotsu M, et al: Production of tetrodotoxin and its derivatives by
Pseudomonas sp. Isolated from the skin of a pufferfish. 1987, 225228.
FAILURE OF ENDTIDAL CARBON DIOXIDE TO
CONFIRM TRACHEAL INTUBATION IN A NEONATE
WITH A SINGLE VENTRICLE AND SEVERE
PULMONARY STENOSIS
- Case Report -
Sahar M. Siddik-Sayyid*, Anis S. Baraka**,
Farah H. Mokadem*** AND Marie T. Aouad****
A 12 day old baby girl (body weight 3.5 kg) with dextrocardia and single ventricle, both
great arteries arising from single ventricle, severe valvular and subvalvular pulmonary stenosis and
hypoplastic pulmonary artery, and non restrictive atrial septal defect, was scheduled for BlalockTaussing shunt under general anesthesia.
On the day of surgery, heart rate (HR) was 139 bpm, noninvasive blood pressure (BP) 93/31
mmHg, SpO2 81% on room air, and temperature 36.5° C. Patient was preoxygenated with 100%
O2, which increased SpO2 to 99%.
Anesthesia was induced by face mask with sevoflurane in oxygen with gradual increase
in concentration to 6%. Immediately after venous access was obtained, propofol 2 mg/kg-1 was
administered. Patient was easy to ventilate and saturation was 99% when intubation was attempted
for the first time. Upon laryngoscopy, vocal cords could be visualized and uncuffed endotracheal
tube (3.0 mm) was inserted easily.
Although the patient was ventilated, and bilateral air entry by auscultation was detected,
no endtidal carbon dioxide (ETCO2) tracing on the monitor could be seen, and the patient started
developing hypoxia (SpO2 60%), and BP decreased to around 40/25 mmHg. Intubation was
considered esophageal and a repeated attempt of intubation with direct visualization of the tube
passing through the vocal cords, showed no improvement in the above findings. Also, patient
developed bradycardia (HR 85 bpm), and was given atropine 10 µg/kg-1. Following a transient
increase of HR to 120 bpm and saturation to 75%, both values dropped again, and still no ETCO2
could be detected. Capnograph was checked and no deficiency could be found. However, the chest
rise observed and bilateral air entry by auscultation confirmed correct placement of the tube. Since
hypotension and bradycardia persisted, a bolus injection of epinephrine 10 µg/kg-1 was given. BP
increased to 70/35 mmHg, HR to 115, and SpO2 to 79%, and low ETCO2 tracing (20 mmHg) could
be detected. When circulation improved, surgery was carried out.
From Department of Anesthesiology, American University of Beirut-Medical Center, Beirut-Lebanon.
*
MD, FRCA, Associate Professor.
** MD, FRCA, Professor.
*** MD, Resident.
**** MD, FRCA, Assoc. Prof.
Address correspondence to: Marie T Aouad MD, Associate Professor, American University of Beirut, Department of
Anesthesiology. P.O. Box: 11-0236 Beirut-Lebanon, Fax: 961 1 745249. E-mail: [email protected]
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M.E.J. ANESTH 20 (2), 2009
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Sahar M Siddik-Sayyid ET. AL
Discussion
reducing concentration of inhaled anesthetic4.
When CO2 is absent as measured by capnograph,
it means either the endotracheal tube is in a wrong
position (esophageal) or there is absent/decreased
presentation of CO2 to the lungs. False negative results
can occur in many situations, where ETCO2 is not
detected, even though the tube is properly placed in the
trachea. Gas sampling problem, such as disconnection
of the tracheal tube from breathing apparatus, apnea,
equipment failure, a kinked or obstructed tracheal
tube, unintentional PEEP to a loosely fitted or
uncuffed tube, and dilution of proximal sampling by
fresh gas flow in Mapelson D systems and Dryden
absorber may be misinterpreted as absent waveform
caused by esophageal intubation. A marked decrease
in pulmonary blood flow will increase alveolar
component of the dead space; this occurs with low
cardiac output, hypotension, pulmonary stenosis,
pulmonary embolism, tetralogy of Fallot, and kinking
or clamping of the pulmonary artery during pulmonary
surgery1.
In our neonate, severe pulmonary stenosis and
single ventricle are expected to produce low ETCO2
values on capnography. Sevoflurane induction
combined with propofol may have caused a further
reduction in the pulmonary blood flow secondary to
reduced systemic vascular resistance, and bradycardia.
As a consequence, the cardiac output dropped
resulting in an increase of the arterial/ETCO2 gradient
and subsequently alveolar dead space. This caused a
completely absent CO2 waveform on capnography
(false negative result). Restoration of the circulation
resulted in the reappearance of the waveform.
Propofol use in children with congenital heart
disease (CHD) may decrease systemic vascular
resistance and lead to a change in the ratio between
systemic and pulmonary flow2,3. Also, propofol
produces bradycardia by its action on the sinoatrial
node and attenuation of the β adrenergic receptors at
the level of the ventricular myocytes. Even a relative
decrease in HR may be deleterious in infants and
young children who depend on HR to maintain cardiac
output as they cannot increase stroke volume. Previous
study found that induction with sevoflurane decreases
BP which returned to baseline values in few min after
References
1. Salem MR, Baraka AS: Confirmation of tracheal intubation. In:
Carin A. Hagberg, ed. Benumof’s Airway management, 2nd edn.
Mosby, 2007, 697-727.
2. Oklu E, Bulutcu FS, Yalcin Y, et al: Which anesthetic agent
alters the hemodynamic status during pediatric catheterization?
Comparison of propofol versus ketamine. J Cardiothorac Vasc
Anesth; 2001, 15:736-739.
Repeated attempts of intubation can be
complicated in cyanotic neonates by deleterious
hypoxia and cardiovascular decompensation.
The apneic episodes during repeated attempts of
laryngoscopy can result in rapid desaturation because
of the low functional residual capacity and high rate of
oxygen consumption of the neonate. Also, the basal low
saturation places the neonate with cyanotic congenital
heart disease in the steep part of the oxyhemoglobin
dissociation curve.
In summary, ETCO2 in neonates with cyanotic
CHD associated with pulmonary stenosis and single
ventricle consistently underestimates the true arterial
CO2 level. Any additional decrease in pulmonary
flow such as that induced by sevoflurane-propofol
combination may render ETCO2 waveform an
inadequate tool to confirm tracheal intubation.
Keywords: Congenital heart disease: pulmonary
stenosis, single ventricle; Capnography: entidal carbon
dioxide; Anesthesia: pediatric.
3. Williams GD, Jones TK, Hanson KA, et al: The hemodynamic
effects of propofol in children with congenital heart disease. Anesth
Analg; 1999, 89:1411-6.
4. Ulke ZS, Kartal U, Sungur MO, et al: Comparison of sevoflurane
and ketamine for anesthetic induction in children with congenital
heart disease. Paediatr Anaesth; 2008, 18:715-21.
UNEVENTFUL EPIDURAL ANALGESIA IN A PATIENT
WITH SEVERE THROMBOCYTOPENIA
- Case Report -
Sami M Ibrahim* and Mustafa Saleh ElGazali**
Abstract
Epidural analgesia is the most effective method for analgesia in labor. It has, however,
contraindications and carries many serious side effects.
Though coagulopathy is an absolute contraindication for epidural and axial blocks, yet there
are no absolute limits for platelet counts that stand in the way of providing epidural analgesia. In a
patient who is writhing in pain due to severe uterine contractions, and in whom there exists a recent
normal platelet screening and no history of bleeding disorders, it is internationally acceptable
between anesthetists to provide epidural analgesia without waiting for a new platelet screening.
Introduction
Although epidural analgesia is the most effective method for analgesia in labor, nevertheless
it carries risky and serious side effects.
Coagulopathy is an absolute contraindication for epidural analgesia and axial blocks. However,
there are no absolute limits for platelet counts beyond which one could refuse to provide epidural
analgesia to relieve labor pain. In a patient tormented with pain due to severe uterine contractions,
and carrying a recent normal platelet screening and no history of chronic hepatic disease, preeclampsia, bruises, ecchymoses, or bleeding disorders, an epidural can be placed with minimal fear
of causing a hematoma.
We report, herein, a patient with normal lab findings who received epidural analgesia. After
vaginal delivery, the epidural catheter was removed, and severe thrombocytopenia was discovered,
with a platelet count of 27 × 109/L, the patient had no subsequent neurologic or hematologic
complications.
Obstetric Anesthetist, Hamad Medical Corporation, Doha-Qatar.
*
MB Bs, M Sc Anesthesia, MD Anesthesia, Assist. Prof. Zagazig Faculty Of Medicine University, Egypt (11/2000).
** MD, Consultant, Anesthesia Dept.-HMC, Doha-Qatar.
Corresponding author: Dr. Sami M Ibrahim, Anesthesia Department, Hamad Medical Corporation. P.O. Box: 3050 DohaQatar, Mobile: 009745621409, Fax: 009744397291, 009744391511. E-mail: [email protected]
291
M.E.J. ANESTH 20 (2), 2009
292
Case Report
A 25 year-old gravida 2 para 1, 76 kg with a
history of previous cesarean section under general
anesthesia, was admitted to the labor room of Hamad
Medical Corporation Hospital of Doha-Qatar, for
trial of labor. Her history revealed that she had an
uncomplicated obstetric history, good natal care and
there were no signs or symptoms or any chronic hepatic,
renal, or autoimmune diseases. The only pertinent
information was that she was taking paracetamol
(acetaminophen) regularly (500 mg tablets three times
daily for ≥1 month), for abdominal and back pain.
There was no history or signs of coagulopathy in the
previous pregnancies and there was no bleeding from
mucus membranes and no petechiae or bruises noted.
The routine hematologic studies were performed two
months prior to admission to labor ward in anticipation
of a normal vaginal delivery, revealed a platelet count
was 200 × 109/L. Other complete blood count data
were within normal limits.
On admission, patient was normotensive with
no albuminuria or manifestations of preeclampsia and
her uric acid level was normal. The options for labor
analgesia were discussed with the patient, and she
chose epidural analgesia. A combined spinal epidural
analgesia at L3-L4 was entertained.
Following skin infiltration with a local anesthetic,
a 16-gauge Tuohy and a 27-gauge spinal needle were
used (combined spinal epidural Minipack: Portex,
CSEcure: Hythe,UK). With the loss of resistance
saline technique, the epidural space was identified.
Twenty-five microgram of fentanyl plus 2.5 mg of
bupivacaine were deposited intrathecally through the
spinal needle. The epidural catheter was then threaded
for 4 cm into the epidural space. The epidural catheter
was secured as usual with a transparent dressing. There
were no signs of intravascular or intrathecal injection,
local anesthetic toxicity, hypotension, arrhythmias or
abnormal changes in the fetal heart, were observed. An
epidural infusion was started of 50 ml mixture of one
mg plain bupivacaine/ml and two mcg of fentanyl/ml,
with the infusion rate ranging between six to sixteen
ml/hour varying with the intensity of labor pain.
Labor progressed as expected (first stage 180
min, second stage 30 min). Patient delivered a healthy
baby, weighing 3300 gm with an Apgar score of 9
S. M. Ibrahim and M. S. elgazali
and 10 at 1 and 5 min respectively. The pediatrician
assessed the baby and whose hematologic studies were
sent to rule out any thrombocytopenic disorders, all of
which revealed no abnormalities. Two hours following
delivery of the placenta and suturing of the episiotomy,
the epidural catheter was removed. Bleeding at
injection site during removal of the catheter was noted,
which was stopped by pressure for 7 min.
Results of the hematologic studies on the sample
obtained before the epidural insertion, revealed a
platelet count of 50 × 109/L (Coulter Counter). This
was confirmed by the manual platelet count and a
peripheral blood smear examination of the platelets,
giving a count of 41 × 109/L and a smear showing
platelets of large size (Fig. 1).
Serial platelet count estimations were then
conducted which manifested a sloping curve of platelet
counts in the ensuing 2 days, returning to around
normal in a month’s time (Fig. 2). It was expected that
Fig. 1
Peripheral blood smear showing a low platelet count with
large size platelets (ITP)
UNEVENTFUL EPIDURAL ANALGESIA IN A PATIENT WITH SEVERE THROMBOCYTOPENIA
293
the platelet count would increase following delivery of
the placenta, but it did not. Within 2 hours, the platelet
count dropped from 50 × 109/L to 27 × 109/L. The
thrombin time was normal at 9.5 sec, and the partial
thromboplastin time was 34 sec. The liver function
tests, although still within the normal ranges, had
doubled; AST increased during 22 hours from 17 to
26 U/L, in the same period ALT increased from 11 to
21 U/L.
450 × 109/L), or even higher. Cyclic thrombocytopenia
a rare manifestation, first described in 1936 and was
related to hormonal changes during menstruation and
changes that occur over days and months3,4. It may also
be of autoimmune origin. It is common in females and
usually leading to increased destruction and short life
span of platelets. It may also be due to amegakaryocytic
origin due to impaired platelet production, usually
more common in males5.
Fig. 2
Platelet count changes curve
In obstetric patients, thrombocytopenia ranges
from benign disorders to life-threatening syndromes6.
The idiopathic type of thrombocytopenia (ITP)
was been diagnosed by peripheral blood smear
examination. It is striking that in our case the changes
in platelet count were rapid over few hours and an ITP
diagnosis was confirmed by the large-sized platelets
in the peripheral blood smear (Fig. 1). The patient had
normal platelet count during her last pregnancy and had
no predisposing signs of coagulopathy and no signs
and symptoms of bleeding dyscrasias in the current
pregnancy. Her blood count done 3 months previously,
revealed a normal platelet count (200 × 109/L). Epidural
analgesia had to be started immediately as the patient
was in severe labor pain. The analgesia guidelines as
adopted in our Institution were implemented (normal
platelet counts, not less than 100 × 109/L within the
previous 2-3 months, and without any predisposing
factors of coagulation deficits).
No signs of epidural hematoma or neurologic
injury were elicited. Patient moved both legs with full
power (Bromberg’s score1 was 2 out of 4 and 1 hour
after the epidural, the motor strength was one out of 4
with normal free movements.
Neurologic assessment every hour during the first
6 hours and then every 2 hours during the remaining 24
hours, revealed no neurologic deficits and no abnormal
vaginal bleeding. Total blood loss was 300 ml, which is
the expected loss after a spontaneous vaginal delivery.
Patient was referred to a hematologist for followup of platelet count and coagulation state. For more
than 2 months, the follow-up did not reveal any
abnormalities in blood cell components and coagulation
studies.
Discussion
The normal range for human platelet levels
is between 150-450 × 109/L. Normally, human
platelet counts remain relatively stable2. In cyclical
thrombocytopenia, however, platelet counts may
oscillate from very low (1 × 109/L) to normal (150-
We know of only one case report in which the
patient received epidural analgesia uneventfully with
a platelet count as low as 26 × 109/L8. This patient
had a history of idiopathic thrombocytopenia (ITP)
which the then attending anesthetist did not ascertain
due to a language barrier. The patient had received
corticosteroids to improve the platelet count.
In our case, the patient had normal blood
components in the previous and current pregnancy. She
had no history of ITP and had normal blood count (200
× 109/L) in the previous 3 months and had received
good antenatal care. It is probable that the patient
platelet count was ≤50 × 109/L at the time of epidural
insertion and which decreased rapidly until delivery,
and then started to improve spontaneously without any
medications.
M.E.J. ANESTH 20 (2), 2009
294
S. M. Ibrahim and M. S. elgazali
In ITP, platelet counts decreases, but the size
and activity of platelet, function is enhanced to
compensate for the decrease in number11 (Fig. 1). This
may explain the absence of hematoma or neurologic
complications.
With regards acetaminophen (paracetamol) there
are studies demonstrating that oral acetaminophen
does not inhibit platelet function in vivo12,13. Other
studies, however, declare that acetaminophen is a nonsteroidal anti-inflammatory drug (NSAID) and may
affect platelet count if used chronically.
Conclusion
It is highly recommended that antenatal care
be provided for all pregnant women and that platelet
counts and coagulation profile should be performed
on admission to the pregnant women with labor pains
to the ER, regardless of whatever previous studies
have shown. Patients should be monitored closely for
any neurologic dysfunction after a neuroaxial block,
especially in conditions with low platelet counts. It is
also recommended that prospective studies of platelet
screening are needed prior to the performance of
epidural analgesia.
Acknowledgement
I would like to thank Dr. André Louon and Dr.
Anjum Suzan John for their unlimited efforts in editing
this case report.
References
1. Bromage PR: Neurologic complications of regional anesthesia
for obstetrics. In: Shnider SM, Levinson G, eds. Anesthesia for
Obstetrics. 3rd ed. Baltimore: Williams & Wilkins, 1993, 443-4.
2. Kuter DJ: The physiology of platelet production. N Engl J Med;
1996, 14:88-101.
3. Aranda E, Dorantes S: Garcia’s disease: cyclic thrombocytopenic
purpura in a child and abnormal platelet counts in his family. Scand
J Haematol; 1977, 18:39-46.
4. Balduini C, Stella C, Rosti V, Bertolino G, Noris P, Acari E:
Acquired cyclic thrombocytopenia thrombocytosis with periodic
defect of platelet function. Br. J. Haematol; 1993, 85:718-722.
5. Beutler E, Lichtman MA, Coller BS, Kipps TJ: Williams
Hematology. New York: McGraw-Hill (1995) (cross reference).
6. McCare PR, Samuels P, Schreiber AD: Pregnancy associated
thrombocytopenia: pathogenesis and management. Blood; 1992,
80:2697-2714.
7. Burrows RF, Kelton JG: Thrombocytopenia at delivery: a
prospective survey of 6715 deliveries. Am J Obstet Gynecol; 1990,
162:731-4.
8. Moeller T, Kuczkowski K, Benumof J: Uneventful epidural labor
analgesia in a parturient with immune thrombocytopenic purpura and
platelet count of 26,000/mm3 which was unknown preoperatively. J
Clin Anesth; 2004, 16:51-53.
9. Boehler F, Hohfeld P, De Moerloose P: Maternal antiplatelets
antibodies in predicting risk of neonatal thrombocytopenia.
Obstetrics and Gynecology; 1999, 93:169-73.
10.Gill PR, Lind T, Walker W: Platelets value during normal pregnancy.
British Journal of Obstetric and Gynacology; 1985, 92:29-33.
11.Morrison R, Crawford J, MacPherson M, Heinstall S: Platelets
behavior in normal pregnancy, pregnancy complicated by essential
hypertension and pregnancy induced hypertension. Thrombosis and
Hamostasis; 1985, 54: 607-11.
12.Seymour RA, William FM, Oxley A, et al: A comparative study of
the effects of asprin and paracetamol (acetaminophen) on platelet
aggregation and bleeding time. Euro J Clin Pharmcol; 1984,
26:567-7.
13.Mielk CH Jr: Comparative effects of asprin and acetaminophen on
hemostasis. Arch Intern Med; 1982, 141:305-10.
THE RATE DEPENDENT BUNDLE
BRANCH BLOCK
- Transition from Left Bundle Branch Block to Intraoperative
Normal Sinus Rhythm - Case Report -
Seema Mishra*, Prashant Nasa# , Gaurav Nirwani Goyal##,
Himanshu Khurana# , Deepak Gupta#
AND Sushma Bhatnagar **
**
**
***
****
Abstract
A chronic hypertensive patient with electrocardiogram (ECG) showing left bundle branch
block (LBBB) was given general anesthesia for right modified radical mastectomy. Her ECG
reverted to normal sinus rhythm intermittently during peri-operative period. This intermittent ratedependent LBBB is a rare entity. Though hypertension is one significant co-morbid condition, the
risk evalution of LBBB during anesthesia only on an ECG finding, is not justifiable. Rather patient
should be investigated further for any cardiac risk.
Keywords: Left bundle branch block, heart-intra ventricular conduction.
Introduction
Left bundle branch block is a major electrocardiographic abnormality in hypertensive patient.
It may signify associated coronary heart disease. Few cases have been reported on such ratedependent LBBB developing intraoperatively in a patient with normal ECG1-5 but without LBBB
preoperatively.
We report a case of preoperative LBBB which reverted to normal sinus rhythm below critical
hear rate, during perioperative period.
Case Report
A 45 year-old 70 kg female diagnosed as a case of carcinoma right breast T2N1Mx (Stage
2) was posted for modified radical mastectomy. Pre-anesthetic evaluation revealed that she was
a known case of hypertension of 6 yrs and was on oral losartan hydrochlorthiazide once a day,
with good control of blood pressure. She gave no history of chest pain, syncope or dyspnea on
exertion. On systemic examination, there was no significant abnormality in the cardiovascular and
respiratory systems.
From Unit of Anesthesiology, Institute Rotary Cancer Hospital (IRCH), Ansari Nagar, New Delhi, All India Institute of Medical
Sciences, Ansari Nagar, New Delhi India, Pin code: -110029.
*
MD, Assistant Professor Anaesthesia.
#
MD, Senior Resident Anaesthesia.
## Senior Research Associate Anaesthesia.
** Associate Professor Anaesthesia.
Corresponding author: Dr. Seema Mishra, Assist. Prof. Anesthesiology, F-33, AIIMS Residential Campus (West), Ansari
Nagar, New Delhi, Pin: 110029, India. Phone: +91-9899061105, Fax.91-11-26588641, E-mail: [email protected]
295
M.E.J. ANESTH 20 (2), 2009
296
Her investigations including complete hemogram,
renal function tests, blood urea, serum creatinine, blood
sugar, liver function test, serum bilirubin, and total
proteins, were within normal limits. Her ECG showed
LBBB. Fine needle aspiration cytology of right breast
was positive for ductal carcinoma. Ultrasonography
abdomen showed incidental finding of chronic
cholecystitis changes and cholelithiasis. Her bone scan
and chest ski gram were normal.
A Dobutamine-stress thallium/99mTc myocardial
perfusion imaging was done by a cardiologist whose
report revealed mildly hypoperfused anteroseptal region
(may be due to breast attenuation or LBBB) and there was
no evidence of stress induced ischemia. Left ventricular
ejection fraction was 66% (normal >65%) with mildly
hypokinetic anteroseptal region. She was taken up for
surgery and a mild risk explained to patient.
Premedication consisted of intramuscular
glycopyrrolate 0.2 mg, fentanyl 100 µg, and
promethazine 25 mg. The induction of general
anesthesia was done with intravenous propofol 2 mg/
kg-1 and fentanyl 2 µg/kg-1. Tracheal intubation 7.5
mm internal diameter cuffed endotracheal tube was
accomplished with intravenous vecuronium 0.1 mg/
kg-1. Anesthesia was maintained with oxygen, nitrous
oxide in 40:60 ratios and 0.5-1% isoflurane. The
patient was mechanically ventilated (tidal volume 8
ml/kg-1 and rate 12 breaths minute-1).
Intraoperatively after 25 minutes of anesthesia,
her ECG reverted to normal sinus rhythm with a
heart rate of 55 ± 3 beats per min, and blood pressure
maintained within normal limits. This reversal to normal
sinus rhythm was observed untill the time of reversal.
However, at the time of reversal of neuromuscular
blockade with inj. neostigmine 0.5 mg/kg-1 and inj.
glycopyrrolate 8 µg/kg-1, ECG started showing a repeat
pre-operative LBBB again with heart rate around 100
± 10 min-1. Total anesthesia time was 90 minutes.
In the ICU, the patient was monitored for one
hour postoperatively, her ECG again returned to
normal sinus rhythm for 10 min at a heart rate of 55 ±
5 min-1. However, soon ECG started showing LBBB
with no symptoms despite adequate pain relief and
normal to stable vital parameters at a heart rate 72
min-1 (Fig. 1).
Seema Mishra ET. AL
Fig. 1
Perioperative electrocardiograms showing intermittent ratedependent left bundle branch block
a) Pre perative
b) Intraoperative
c) During Reversal
d) Post Operative
THE RATE DEPENDENT BUNDLE BRANCH BLOCK
The postoperative period remained uneventful
except for asymptomatic LBBB. Holter examination
showed that the ECG changes were rate-dependent left
bundle branch block.
Discussion
Left bundle branch block is major clinical
finding in cases of known hypertension. It may also
signify associated coronary artery disease, aortic valve
disease or cardiomyopathies6. Isolated left bundle
branch block in a healthy young adult may be benign,
but in hypertensive or older patients it may signify
a progressive degenerating myocardium involving
cardiac conduction system7-9.
The stress-perfusion imaging of the patient
showed a relatively normal cardiac performance.
Her ECG which was showing LBBB preoperatively,
became normal peri-operatively at a heart rate of <60
beats per minute.
Our hypothesis is that the LBBB in the present
case was not of organic origin as proved by stressperfusion imaging and the fact that LBBB reverted
back to normal sinus rhythm. When heart rate was at 60
± 10 beats per minute intraoperatively, and especially
postoperatively for some time, LBBB reverted to sinus
rhythm. So pre-operative abnormal ECG rhythm was
rate-dependent LBBB, reverting into normal sinus
rhythm at lower heart rates (critical heart rates).
The rate-dependent bundle branch block is
defined as an intraventricular conduction defect that
may return, if only temporarily, to sinus rhythm at
lower heart rates9. The exact mechanism of such a
block is unclear but may result from anatomic or
physiological interruptions in cardiac conduction
system either due to ventricular enlargement or from
297
neurogenic or functional depression with or without
underlying pathological lesions of the conducting
tissue10. Rate-dependent bundle branch block can
revert to sinus rhythm at critical heart rate11. The
transition from normal to abnormal may occur by
alterations in heart rate by only 1 or 2 beats/min-10. This
critical heart rate is dependent on change in heart rate3.
With rapid decrease in heart rate, sinus rhythm may
appear at higher rates and with rapid acceleration in
heart rate, it may appear at lower heart rate, as the heart
rate increase RR interval shortens and the descending
impulses finds one of the bundle branches still in its
refractory period9.
A clear differentiation of LBBB into a benign
rate-dependent LBBB, and LBBB associated with
myocardial ischemia or infarction, may avoid the
unnecessary postponement of a case because of high
cardiac risk. Various convenient methods exist for the
diagnoses of rate-dependent LBBB during anesthesia.
Manouvers like carotid massage, deep inspiration and
pharmacological agents like esmolol12, metoprolol6,
propanolol, neostigmine and edrophonium which all
decrease the heart rate and thus change this aberrant
conduction block to normal13. Holter examination,
however, is the gold standard.
In a chronic hypertensive patient with LBBB,
it is always better to do further cardiac evaluation,
like stress-imaging, in order to rule out an associated
CAD.
In conclusion, rate-dependent left bundle branch
block is a rare entity. LBBB with other co morbid
condition, like hypertension, though a significant
finding, yet the evaluation of risk during anesthesia
only on an ECG finding, is not justifiable. Rather
patient should be further investigated for any associated
cardiac co morbid conditions.
M.E.J. ANESTH 20 (2), 2009
298
Seema Mishra ET. AL
References
1. Rorie DK, Muldoon SM, Krabill DR: Transient bundle branch
block occurring during anesthesia. Anesthesia Analgesia; 1972,
51:633-637.
2. Elderman DM, Hurlbert BJ: Intermittent left bundle branch block
during anesthesia. Anesthesia Analgesia; 1980, 59:628-630.
3. Domino KB, La Mantia KL, Geer RT, Klineberg PL: Intraoperative
diagnosis of rate-dependent bundle branch block. Can Anesth Soc J;
1984; 31:302-306.
4. Reyford H, De Groote P, Guermouche T, Boufflers E, Menu H,
Adnet P: Intermittent left bundle branch block revealed during
anaesthesia. British Journal of Anaesthesia; 1994, 72:700-701.
5. Tyagi A, Sethi AK, Agarwal V, Mohta M: Rate-dependent left
bundle branch block during anaesthesia. Anaesthesia and Intensive
Care; 2004, 32:715-718.
6. Littmann L, Symnaski JD: Hemodynamic complications of left
bundle branch block. J Electrocardiology; 2000, 33 suppl: 115-121.
7. Grady TA, Chiu AC, Snader CE, et al: Prognostic significance of
exercise- induced left bundle branch block. JAMA; 1998, 279:153156.
8. Fahy GJ, Pinski SL, Miller DP, et al: Natural history of isolated
bundle branch block. American Journal of Cardiology; 1996;
77:1185-1190.
9. Intraventricular Conduction defects. In: Wagner GS, ed. Marriott’s
Practical Electrocardiography. Lipincott Williams & Wilkins,
Philadelphia, 2001, 96-116.
10.Bauer GE. Transient Bundle branch Block. Circulation; 1964,
29:730-738.
11.Josephson ME: Intraventricular conduction disturbances. In:
Clinical Cardiac Electrophysiology: Techniques and Interpretations.
Lipincott Williams & Wilkins, Philadelphia, 2001, 110-139.
12.Rajesh, Bhoi S, Kumar M, Sharma B, Gupta BB. Rate dependent
left bundle branch block with chest pain in a 38 year old female. J
Ind Acad Clin Med; 2002, 3:193-194.
13.Wallace AG, Laszlo J: Mechanism influencing conduction in a case
of intermittent bundle branch block. Am Heart J; 1961, 61:548-555.
INTUBATION-INDUCED TRACHEAL STENOSIS
- The urgent need for permanent solution - Case Report -
Ali S Al-Qahtani*, And Farouk M Messahel**
Abstract
The most common site for the occurrence of intubation-induced tracheal damage is at the area
in contact with the inflatable cuff. After the change from high-pressure to low-pressure cuffs, major
tracheal lesions still continue to occur. This is a case of tracheal stenosis that occurred after 7 days
of intubation with standard cuffed tube whose cuff pressure was assessed by subjective means.
Three weeks later, patient was in need of reintubation, the trachea was found to be stenotic at the
site of the previous tube cuff. Emergency tracheostomy had to be performed and computed axial
tomography (CT) confirmed the tracheal stenosis. A month later, the patient had another cardiac
arrest from which he did not recover. Our message in this report is to throw light and alert clinicians
involved in tracheal intubation, of the presence of the Lanz endotracheal tube whose pilot balloon
is designed to automatically regulate the intra-cuff pressure and thus prevent the occurrence of
tracheal stenosis due to high pressure. We strongly recommend the presence of Lanz tracheal tubes
as standard emergency equipment in intensive care settings and in any situation in which cuff
pressure is likely to increase.
Keywords: Tracheal Stenosis, Postintubation Tracheal Stenosis, Tracheostomy.
Introduction
When the high-volume low-pressure cuffed tracheal tubes were introduced into clinical
practice more than 3 decades ago, hopes were high that major tracheal damage associated with
the previously used high-pressure cuffed tubes would be eliminated. However, tracheal stenosis is
still occurring, and in one prospective study of critically ill patients, 11% of patients who had been
intubated with high volume low pressure cuffed tubes, developed tracheal stenoses that were 1050% of their tracheal diameter at the cuff site1. Other reports showed more severe tracheal damage
at the cuff site2. This is a case report of tracheal stenosis following a week long intubation.
We believe that tracheal intubation is here to stay, albeit for the foreseeable future. Monitoring
tracheal cuff pressure by simple devices has decreased the incidence of cuff-related tracheal
damage. However, such practice is tedious and time-consuming, in addition it did not eliminate the
occurrence of the damage4. To avoid the occurrence of tracheal stenosis, we strongly recommend
anesthesiologists and intensivists to be aware of the presence of the Lanz tracheal tube, whose pilot
balloon is designed to automatically regulate the intra-cuff pressure.
*
**
JB, KSUF, Assist. Prof. & ENT/Head and Neck Surgeon, King Khalid Univ., Abha, Kingdom of Saudi Arabia.
DA, FRCA, Senior Consultant Anaesthetist, Armed Forces Hospital-Southern Region, Khamis Mushayt, Kingdom of Saudi
Arabia.
Corresponding author: Dr. Ali S Al-Qahtani, Assist. Prof. and ENT/Head and Neck Surgeon, King Khalid University. PO.
Box: 3877, Abha 61481, Kingdom of Saudi Arabia. Mobile: +966504433309, Fax: +96672245797,
299
M.E.J. ANESTH 20 (2), 2009
300
Case Report
A 51 year-old, a known hypertensive hospital
male employee, developed a cardiac arrest while
playing basketball. He received advanced life support
resuscitation, at the end of which he was deeply
comatosed with Glasgow Coma Scale of 4. Patient
was mechanically ventilated for seven days until his
condition improved then his trachea was extubated.
His oxygen saturation was 98% on breathing room air.
However, it was noted that he already developed right
hemiparesis and dysphasia.
On the 21st post-extubation day, the patient was
in obvious respiratory distress with falling oxygen
saturation. Attempts at passing decreasing sizes of
tracheal tubes were unsuccessful, at which stage
tracheal stenosis was diagnosed and an emergency
tracheostomy was performed. Computed axial
tomography (CT) was done and confirmed the
diagnosis (Fig. 1). Unfortunately a month later, the
patient had another cardiac arrest from which, he could
not recover.
Ali S Al-Qahtani ET. AL
within a similar period if the cuff pressure increases to
greater than 40 mmHg4.
An increase in tracheal cuff pressure occurs when
nitrous oxide is administered to an intubated patient
under general anesthesia7,8. In the ICU, however nitrous
oxide is rarely used, in such situation an increase in
cuff pressure is the result of injecting excess air into
the cuff or the use of opioids, widely used in intensive
care settings. Morphine may result in a 21% increase
in cuff pressure, while the increase in cuff pressure
after fentanyl may reach 44%9.
Tracheal stenosis after intubation usually presents
as shortness of breath and either or both inspiratory
stridor and expiratory wheeze on exertion10. Changes
in the flow-volume loop are diagnostic of tracheal
stenosis (Fig. 2a & 2b).
Fig.2a
Normal Flow-Volume Loop
Fig. 1
Computed axial tomogram at the level of the stenotic trachea
Fig. 2b
Fixed Airway Obstruction (as in tracheal stenosis)
Discussion
The introduction of the tracheal tubes with low
pressure cuffs have led to the erroneous belief that
cuff-related tracheal damage has been prevented4. In
fact, once the wall of the tracheal tube cuff comes in
contact with the mucous lining of the inside of the
trachea, small amounts of air injected into the cuff may
result in steep increases in cuff pressure5. Changes in
the tracheal mucosa may occur as early as 15 min after
inflation of the cuff6, and ischemic damage may result
INTUBATION-INDUCED TRACHEAL STENOSIS: THE UGENT NEED FOR PERMANENT SOLUTION
301
Tracheal lesions related to excessive cuff pressure
may be totally eliminated if the Lanz tracheal tube is
used as a standard in intensive care settings and in any
situation an increase in cuff pressure is likely11-12. The
Lanz pilot balloon has been developed to automatically
control and regulate intra-cuff pressure, without the
need for additional monitoring. Injecting approximately
40 ml of air to achieve an intra-cuff pressure of 22-25
mm Hg, the system will automatically maintain cuff
pressure at a constant level below 25 mm Hg (34 cm
H2O). (The mean capillary perfusion pressure in the
tracheal wall is about 35 mm Hg [48 cm H2O]). Any
increase in the volume of the tracheal cuff will be offset
automatically by regulating valve and will move to the
pilot balloon which is visible through outer transparent
balloon (Fig. 3a & 3b). The balloon and control valve
continuously regulate cuff pressure avoiding over-or
underinflation. It also maintains safe cuff pressure at
varying altitudes during air transportation.
Fig. 3a
The pilot balloon of the Lanz tracheal tube
Fig. 3b
The pilot balloon that can automatically
regulate intra-cuff pressure
In conclusion, the aim of this presentation is
to alert the awareness of the many anesthesiologists
and intensivists to the existence and use of the Lanz
endotracheal tube whose automatic pilot-balloon
regulating of the cuffed-pressure, thus providing quality
medical care, and avoiding considerable patients’
morbidity with its associated human and medical costs.
In emergency situations where resuscitation takes place
by the available means and the standard endotracheal
tube (Fig. 4) is used, this tube can be replaced by a
Lanz endotube when patent is in the ICU. It is therefore
highly recommended that the Lanz tube should be an
integral part of emergency equipment in the ICU.
Fig. 4
Standard endotrachcal tube
M.E.J. ANESTH 20 (2), 2009
302
Ali S Al-Qahtani ET. AL
References
1. Stauffer JL, Olson DE, Petty TL: Complications and consequences
of tracheal intubation and tracheostomy. A prospective study of 150
critically ill adult patients. American Journal of Medicine; 1981,
70:65-76.
2. Sarper A, Ayten A, Eser I, Demircan A, Isin E: Review of
posttracheostomy and postintubation tracheal stenosiswith special
regard to etiology and treatment. The Internet Journal of Thoracic
and Cardiovascular Surgery; 2003, volume 6, number 1.
3. Grillo HC: Management of nonneoplastic diseases of the trachea. In:
Shields TW, Cicero JL, Ponn RB: eds. General Thoracic Surgery, 5th
ed. Philadelphia: Lippincott Williams and Wilkins, 2000, 85-897.
4. Messahel BF: Total tracheal obliteration after intubation with a lowpressure tracheal tube. British Journal of Anaesthesia; 1994,73:697699.
5. Messahel FM: Postintubation tracheal damage. A four-year
prospective study. Middle East Journal of Anesthesia; 1992, 11:443453.
6. Dorsch A, Dorsch SE: Understanding Anesthesia Equipment, 2nd
ed. Baltimore: Williams and Wilkins, 1984.
7. Wu W, Lim I, Simson FA, Turndorf H: Pressure dynamics of
endotracheal and tracheal cuffs. Critical Care Medicine; 1973,
1:197-202.
8. Seegobin RD, Van Hasselt GL. Endotracheal cuff pressure and
tracheal mucosal blood flow: endoscopic study of effects of four
large volume cuffs. British Medical Journal; 1984, 288:965-968.
9. Bemhard WN, Yost L, Turndorf H, Danziger F: Cuffed tracheal
tubes-Ohysical and behavioural characteristics. Anesthesia and
Analgesia; 1982, 61:36-41.
10.Saarnivaara L, Grahne B: Clinical study on an endotracheal tube with
a high-residual volume, low-pressure cuff. Acta Anaesthesiologica
Scandinavica; 1981, 25:89-92.
11.Leigh JM, Mynard JP: Pressure on the tracheal mucosa from cuffed
tubes. British Medical Journal; 1979, 1:1173-1174.
12.Honeybourne D, Costello JC, Barham C: Tracheal damage after
endotracheal intubation: comparison of two types of endotracheal
tubes. Thorax; 1982, 37:500-502.
OBSTRUCTION OF ENDOTRACHEAL TUBE;
A MANUFACTURING ERROR
- Case Report -
Fatemeh Hajimohammadi*, Arman Taheri**
and Payam E ghtesadi -A raghi ***
Manufacturing defects in endotracheal tubes (ETT) are known to occur, and may cause ETT
obstruction in various ways-1. We report an ETT manufacturing error resulting in partial airway
obstruction with a 7.0 mm cuffed tube due to partial perforation of the distal orifice of the ET tube.
Case Report
A fourteen-year-old girl 49 kg, ASA I with chronic sinusitis was scheduled for an
elective functional endoscopic sinus surgery. Monitoring equipment including pulse oxymeter,
sphygmomanometer, and ECG were applied and her basic vital signs were within normal range.
Patient was premedicated with midazolam 2 mg and fentanyl 100 µg, via an IV route.
Anesthesia was induced with thiopentone 250 mg and muscle relaxation was achieved using 25 mg
atracurium. The trachea was intubated with a cuffed oral PVC ETT (Supa high volume-low pressure
cuff, single use, ID = 7.0 mm) without any complication. ETCO2 monitoring was established and
bilateral lung expansion confirmed by auscultation although bag ventilation was difficult because
of high inspiratory pressure. Then the lungs were artificially ventilated at tidal volume of 500 ml
(end-tidal CO2 of 40 mmHg) and rate of 10 breaths per minute with a mixture of oxygen, nitrous
oxide (50%) and halothane (1%) for anesthesia maintenance.
Before preparation and draping, a pharyngeal pack was inserted. After several minutes, the
peak airway pressure increased from 30 to 65 cmH2O gradually. This was accompanied by heart
rate increase (120 beat/min) and end-tidal CO2 rise to 60 mmHg. SaO2 remained unchanged at
100% with FiO2 of 50%.
Upon noting the rise in ETCO2 and drop in expired tidal volume, the patient was immediately
disconnected from the ventilator and the lungs ventilated manually, nitrous oxide was discontinued
and pharyngeal pack was removed. The circuit was checked systematically for kinks, obstructions
or leaks, but none was found. ETT marking at the incisor was checked and remained the same at 18
cm. Lung auscultation revealed expiratory wheezing. Visual inspection of the ETT did not reveal
any cause of airway obstruction. A 10F suction catheter was then passed down the lumen of the
ETT for suctioning of secretion but the suction catheter could not be passed fully down the tube and
resistance was encountered. After that, the surgery was delayed and patient’s ETT was substituted
From Department of Anesthesiology and Critical Care, Amiralam Hospital, Tehran University of Medical Sciences, Tehran, Iran.
*
MD, Assistant Professor of Anesthesiology.
** MD, Assistant Professor of Anesthesiology.
*** MD, Anesthesiologist, President of Parsteb Pajouheshyar Medical Sciences Research Institute, Tehran, Iran.
Corresponding author: Payam Eghtesadi-Araghi, MD, Anesthesiologist, President of Parsteb Pajouheshyar Medical
Sciences Research Institute, Department No. 5, 37th (Eastern), First Golzar St., Ashrafi Esfahani Bulv., Ponak Sq., Tehran
1476783476, Iran. Tel & Fax: (+98) 21-44454814, E-mail: [email protected]
303
M.E.J. ANESTH 20 (2), 2009
304
with another same size new cuffed ETT under direct
laryngoscopy which resulted in marked improvement
in ventilation.
Examination of the former tube revealed that
there was as a manufacturing error (Fig. 1) consisting
of a plastic film covering the distal opening of the
tube with a small perforation (approximately 2.5 mm
in diameter) at its mid-upper point. The subsequent
anesthetic course was uneventful.
Fig. 1
Plastic film at the distal end of the ETT that was removed from
the patient. Arrow shows the orifice in the plastic film with
diameter of approximate 2.5 mm
Fatemeh Hajimohammadi et. al
level of the notch cut for insertion of the pilot tube
causing air leak8,9 kinking of the ETT3,4 and intraluminal
plastic films and meniscus4,10 causing near complete
airway obstruction.
The checking of ETT for defects before tracheal
insertion is an integral part of routine checking of
anesthetic equipment. This usually includes examining
the tube to ensure patency and inflating the cuff to
detect air leakage3. In our case, routine check of the
ETT failed to find the structural problem at the tube end
hole. Only after intubation and ventilation for a period
of time did the structural defect become obvious.
Barst et al4 and Kee10 have described similar
cases. Barst et al4 described a 6-months-old girl that
was intubated with an uncuffed 3.5 mm-internaldiameter Sheridan ETT and following no air entry
confirmation she was reintubated with new tube. On
inspection, the tube’s lumen was entirely occluded
by a plastic meniscus that must have been introduced
during the tube’s manufacturing process.
As this case demonstrates, the intrinsic occlusion
of the ETT itself should be considered. Increasing
airway peak pressure on a volume control mode
of ventilation and persistently high ETCO2 due to
hypoventilation were the only early warning signs. The
suction catheter was unable to pass through the tube
due to the distal end block as the tube was occluded
with a plastic film.
This incident was reported to the Supa Corporation
together with the tube’s Lot number.
Discussion
Difficulty in ventilating an intubated patient
during anesthesia may be ascribed to a variety of
causes, basically including anesthesia gas delivery
malfunction, obstruction of the breathing circuit
(somewhere between the common gas outlet and
the end of the ETT), poor pulmonary compliance
(extrinsic or intrinsic), esophageal intubation or
acute bronchospasm, tension pneumothorax, and
endobroncial mass lesion4.
Several manufacturing defects in ETT have
been described. These include cuff defects leading to
herniation of the ETT cuff and intraluminal tracheal
obstruction5,7, elliptical defects in the tube wall at the
Although this occurrence is rare, we feel that it is
timely to highlight this case to relay that any structural
defects in the tube may result in significant airway
incidents.
In conclusion, inspection of ETT prior to use is
still the most crucial factor in confirming tube function.
Vigilant monitoring of ventilator pressure and end
tidal CO2 is the key to the early detection of airway
obstruction. When airway obstruction is encountered
in an intubated patient, it is important to consider both
mechanical and pathologic factors. In cases where no
other cause for inadequate ventilation is found, it is
imperative to replace the ETT.
OBSTRUCTION OF ENDOTRACHEAL TUBE; A MANUFACTURING ERROR
305
References
1. Lee YW, Lee TS, Chan KC, Sun WZ, Lu CW: Intratracheal kinking
of endotracheal tube. Can J Anaesth; 2003, 50:311-2.
2. Szekely SM, Webb RK, Williamson JA, Russell WJ: The Australian
Incident Monitoring Study. Problems related to the endotracheal
tube: an analysis of 2000 incident reports. Anaest Intensive Care;
1993, 21:611-6.
3. Chua WL, Ng AS: A defective endotracheal tube. Singapore Med J;
2002, 43:476-8.
4. Barst S, Yossefy Y, Lebowitz P: An unusual cause of airway
obstruction. Anesth Analg; 1994, 78:195.
5. Henderson MA: Airway obstruction with a cuffed single-use plastic
endotracheal tube. Anaesth Intensive Care; 1993, 21:370-2.
6. Dunn HC: A defective endotracheal tube. NZ Med J; 1988, 13:101460.
7. Famewo CE: A not so apparent cause of intraluminal tracheal tube
obstruction. Anesthesiology; 1983, 58:593.
8. Lewer BM, Karim Z, Henderson RS: Large air leak from an
endotracheal tube due to a manufacturing defect. Anesth Analg;
1997, 85:944-5.
9. Gettelman TA, Morris GN: Endotracheal tube failure: undetected
by routine testing. Anesth Analg; 1995, 81:1313.
10.Kee WD: An unusual problem with an endotracheal tube. Anaesth
Intensive Care; 1993, 21:247-8.
M.E.J. ANESTH 20 (2), 2009
TRACHEAL CARTILAGE FRACTURE WITH THE
PERCUTANEOUS DILATATIONAL
TRACHEOSTOMY, CIAGLIA METHOD
- Case Report -
Kasra Karvandian*, Ata Mahmoodpoor**,
Mostafa Mohammadi*, Mohammadtaghi Beigmohammadi*
and A fshin J afarzadeh ***
Surgical tracheostomy was first introduced by an ENT surgeon (Chevalier Jackson) in 1900.
In 1955, Seldinger, a Swedish radiologist, introduced a way of insertion of a tube with the aid
of a guidewire into the hollow spaces of body, such as blood vessels. In 1985 Pasquale Ciaglia
performed percutaneous dilatational tracheostomy (PDA) with the Seldinger method.
Tracheostomy nowadays is usually performed as PDT in the ICUs1. Most of the PDT methods
are performed with the Seldinger method. The basic difference between the various PDT methods,
however, is in both the way of dilation and the way of dilator entrance (antegrade vs retrograde).
In the Ciaglia method, several dilator tubes are used for tracheal dilation2.
Case Report
A 29 year old man was admitted to ICU because of convulsions and decline in the level of
consciousness, with the diagnosis of encephalitis.He underwent an endotracheal (ET) intubation and
was put on mechanical ventilation.. Twenty days after ICU admission, because of the anticipated
long duration of ET intubation and low level of consciousness, a PDT was performed with the
Ciaglia method.
Patient was sedated with fentanyl and midazolam. Oral cavity and pharynx were locally
anesthetized with lidocaine. The ET tube was withdrawn as tube cuff was placed between vocal
cords using bronchoscope. Angiocath was inserted between the first and second tracheal cartilages
and a guidewire was inserted through it.. The angiocath was then withdrawn and dilator was
guided to trachea.. During insertion, the inferior (second) cartilage got broken as confirmed by
the bronchoscope. The tracheostomy tube was inserted and its correct position confirmed with
bronchoscopy and chest x-ray. The patient was under close observation, and two weeks later, he
was weaned from ventilator. For the following two months patient did not have any complication
due to the fractured tracheal cartilage.
From Department of Anesthesiology and Intensive Care Unit, Imam Khomeini Hospital, Tehran University of Medical Sciences,
Iran.
*
MD, Assist. Prof.
** MD, Anesthesiologist, Fellowship in Critical Care Medicine.
*** MD, Anesthesiologist.
Corresponding author: Dr. Ata Mahmoodpoor, No: B3, Aftab Residential Tower I, Nezami Street, Vali Asr, Tabriz, Iran.
Phone: +989141160888, E-mail: [email protected]
307
M.E.J. ANESTH 20 (2), 2009
308
Kasra Karvandian et. al
Discussion
Patients with long duration of ET intubation
require tracheostomy. The indications for surgical
tracheostomy and PDT are the same. The advantages
of PDT over the surgical method, consists of
decreased bleeding, less tissue incision and injury, less
complications, its rapid and cost saving3-6. In addition,
long term complications, such as tracheal stenosis and
late would healing, are less with PDT method7,8.
In view of such advantages of PDT, nowadays
patients in ICU undergoe PDT unless a contraindication
exists9,10.. Anterior neck infection and coagulopathy
are absolute contraindications for PDT method. Large
goiter, previous history of neck surgery, less than 17
years old, hypoxemia with positive end expiratory
pressure more than 20 cmH2O, FiO2 more than 70%,
morbid obesity, or inability to define the tracheal
cartilage, thyro-hyoid distance less than 3 cm and
emergent situations, are relative contraindications11-13.
Fig.1
PDT at upper levels of trachea of produces increased
pressure on lower cartilage rings.
Tracheal cartilage fracture is one of the
complications of PDT with the Ciaglia method
attributable to tracheal anatomy (trachea is angulated
backwards as it inserts in the thorax). In the performance
of PDT at upper levels, therefore, more force is needed
and inserting dilator into the intercartilage space near
cricoid cartilage (between the first and second tracheal
rings), increases the risk of a fracture. Because the
cricoid cartilage is denser than other cartilages, the
inserting force and pressure on it are transported
to lower tracheal rings, thus increasing the risk of
cartilage fracture, especially in patients with short neck
and limitation of neck movement.. Performing PDT
with Ciaglia method from the lower levels of trachea
produces less force angle, so dilator and trachea are
positioned in nearly straight line (Fig. 1, 2).
It is recommended, therefore, that PDT with
Ciaglia method be done in lower levels of trachea, than
in the first tracheal cartilages.
Fig.2
PDT at lower levels of trachea produces less force angle,
bringing dilator and trachea to a nearly straight line.
VENTRICULO-PERITONEAL SHUNT SURGERY
IN AN INFANT WITH DOUBLE AORTIC ARCH,
PATENT DUCTUS ARTERIOSUS
AND ATRIAL SEPTAL DEFECT
- Case Report -
Mandeep Singh , Ashish Bindra1 , Girija P Rath2 ,
Vishwas Malik2 and Hemanshu Prabhakar1
1
*
*
**
**
***
Abstract
Double aortic arch with patent ductus arteriosus and atrial septal defect is an uncommon
association. Such complex cardiac lesions may complicate an otherwise normal anesthetic course.
We came across a case with aqueductal stenosis and hydrocephalus, scheduled for ventriculoperitoneal shunt surgery, on an emergent basis. The child was managed successfully. The anesthetic
implications of resultant left-to-right shunt with increased intracranial pressure have been
described.
Key Words: Double aortic arch, Patent ductus arteriosus, Atrial septal defect, Anesthesia.
Introduction
Double aortic arch is a rare but life threatening condition, if misdiagnosed1. Its association with
patent ductus arteriosus (PDA) and atrial septal defect (ASD) has been mentioned in association
with few genetic abnormalities2,3. However, the anesthetic implications of this association in
patients undergoing neurosurgical procedures have never been described in literature.
We present a case of congenital hydrocephalus due to aqueductal stenosis, with associated
double aortic arch, PDA, and ASD, scheduled for an emergency ventriculoperitoneal (VP) shunt
surgery.
From Departments of Neuroanaesthesiology1 and Cardiac Anaesthesiology2 All India Institute of Medical Sciences, New Delhi,
India.
1
MD, Senior Resident.
2
MD, DM, Assist. Prof.
1
MD, Assist. Prof.
Address for Correspondence: Dr. Girija Prasad Rath, Assist. Prof., Department of Neuroanaesthesiology, Neurosciences
Centre, All India Institute of Medical Sciences, New Delhi-110029, India. Tel: 91-986839820,
Fax: 91-11-26568663. E-mail: [email protected]
309
M.E.J. ANESTH 20 (2), 2009
310
Mandeep Singh ET. AL
with periventricular ooze. This child was posted for an
emergency ventriculoperitoneal shunt surgery in view
of the raised intracranial tension and deterioration of
neurological condition.
Case Report
A 3-months-old male baby weighing 4 kg was
admitted to our hospital with complaints of increasing
size of head and upward gazing of eyeballs, for the
previous 15 days. This was associated with vomiting
and decreased feeding for 2 days. There was no history
of seizures or focal neurological deficit. The antenatal
history was remarkable for breach presentation and
cesarean section delivery from a polyhydramnios
mother, at 38 weeks of gestation. He developed
bronchopneumonia during the first month of life
which improved following antibiotic treatment. On
examination, the child was pale but, there was no
cyanosis, jaundice, clubbing, or pedal edema. The
heart rate was 116 beats.min-1, and respiratory rate 28
breaths.min-1. He had features of hydrocephalus with
increased head circumference (42 cm), open and tense
fontanelles, and presence of sunset sign. It was noticed
that the baby developed bluish discolouration of mouth
and lips while crying. On cardiac auscultation systolic
murmur was audible. Chest X-ray showed a globular
cardiac silhouette with cardiomegaly, bilateral hilar
prominence and thickening of bronchovascular
markings. ECG showed normal sinus rhythm with no
evidence of ventricular hypertrophy. Echocardiography
revealed a complex congenital heart disease with
presence of ASD (ostium secundum type), PDA,
and double aortic arch. There was no evidence of
pulmonary hypertension. Peripheral arterial pulsations
were feeble bilaterally in the upper limb, whereas
they were well felt in the lower limbs. The oxygen
saturation on room air was 99%. The child had a
reducible umbilical hernia and hypospadiasis as well.
Routine blood tests were within normal limits with
a hemoglobin level of 14 g/dl. MRI of brain showed
gross hydrocephalus with aqueductal stenosis and
corpus callosum agenesis. Non-contrast CT scan head
showed hydrocephalus and dilated lateral ventricles
In the operation theatre, inhalational induction
was performed using sevoflurane in oxygen and air
mixture. After securing an intravenous (IV) access,
fentanyl 2 mcg.kg-1 and rocuronium 1 mg.kg-1 was
given. Tracheal intubation was facilitated using a 3.5
mm ID uncuffed endotracheal tube. Anesthesia was
maintained with sevoflurane in oxygen (FiO2 -0.5)air mixture, fentanyl, rocuronium, and intermittent
positive pressure ventilation. Monitoring parameters
included ECG, non-invasive BP, SpO2, end-tidal CO2,
and inspired concentration of inhalational agents.
The end-tidal CO2 was kept between 33 ± 2 mmHg.
Posterior tibial artery was cannulated for continuous
BP monitoring. Intraoperatively, the mean BP was
targeted to keep within 10% of the baseline values.
However, there was no episode of desaturation or
hemodynamic instability. Serial arterial blood gas
analysis revealed metabolic acidosis (Table 1), which
was managed with IV supplementation of sodium
bicarbonate (4.2%) solution.
Total duration of procedure was 90 minutes. The
blood loss was approximately 20 ml, and a total of 80
ml Ringer’s lactate was used as maintenance fluid.
Temperature was maintained around 36ºC. At the
end of procedure, residual neuromuscular blockade
was reversed with neostigmine and glycopyrrolate,
and trachea extubated, uneventfully. The child was
observed in the intensive care unit for 24 hours.
Though metabolic acidosis persisted (Table 1), further
bicarbonate supplementation was stopped as the child
was clinically stable. He was discharged on third
postoperative day with an advice for further cardiac
evaluation. At 1-month follow-up, the child had
improved neurological status.
Table 1
Perioperative arterial blood gas (ABG) analysis
pH
pO2
(mmHg)
pCO2
(mmHg)
HCO3(mmol/L)
BE
SaO2
(%)
Na+
(mmol/L)
K+
(mmol/L)
Ca++
(mmol/L)
After induction
7.22
184
35.9
14.2
-12.1
100
139
3.9
1.21
Intraoperative
7.254
234
38.0
16.3
-9.6
100
139
3.8
1.05
Postoperative (ICU)
7.288
190
34.6
16
-9.3
100
139
4.2
1.12
V-P SHUNT SURGERY IN AN INFANT WITH DOUBLE AORTIC ARCH, PDA & ASD
Discussion
The anesthetic challenge, in this case, is due to
the combined presentation of left-to-right shunt with
hydrocephalus. Patients with increased intracranial
pressure require hyperventilation to reduce cerebral
blood flow, at the same time keeping adequate PaO2.
On the other hand, the anesthetic management of a
patient with left-to-right shunt includes avoidance
of pulmonary vasodilation by lowering FiO2 and/ or
hypoventilation.
Double aortic arch results from an anomalous
persistence of fourth aortic arch4. It causes formation
of a vascular ring around esophagus and trachea,
producing pressure effects. Infants with double aortic
arch or vascular rings may present with harsh cry,
inspiratory stridor, respiratory distress, and dysphagia.
Airway obstruction may be significant in infants and
children with vascular rings4. Inhalational induction
is preferred, as it serves to maintain spontaneous
ventilation. The tracheal compression can worsen
during induction. Paralysis should be administered only
after ascertaining ability to ventilate using intermittent
positive pressure ventilation. These patients would
require smaller than expected endotracheal tube size.
However, in this case, we did not encounter any such
problem.
Non-cardiac congenital anomalies are commonly
associated (50 to 80%) with these patients4. Congenital
cardiac anomalies are also present in 20% of children
with double aortic arch5. Our patient presented with
a combination of PDA and ASD (ostium secondum).
This combination causes a substantial left-to-right
shunt, resulting in increased volume loading of both
the ventricular chambers, decreased cardiac output, and
increased intra-cardiac and intra-pulmonary pressures.
Deterioration of gas exchange and congestive cardiac
failure may occur when compensatory mechanisms
fail to keep up with excess cardiac work. Decreased
311
systemic blood flow in the presence of left-to-right
shunt as a result of PDA can cause pulmonary over
circulation. This results an elevation of left atrial
pressure due to augmented pulmonary venous return.
Diastolic blood pressure may be compromised if
cardiac output is reduced or there is a low resistance
vascular bed, as in our case. Infants with greatly
increased pulmonary blood flow suffer from congestive
heart failure secondary to increased volume overload.
Obstruction of the large and small airways results in
increased airway resistance and poor compliance. The
inspiratory pressure needed for adequate positivepressure ventilation must be adjusted accordingly.
Hyperoxia and hypocarbia cause pulmonary
vasodilatation. Hence, it is advisable to reduce the FiO2
and to avoid hyperventilation. Normocapnia is helpful
in managing the increased pulmonary blood flow
resulting from such complex heart disease. However,
in this case, mild hypocapnia was maintained without
any untoward event, in order to reduce the intracranial
pressure (ICP). Nitrous oxide (N2O) is best avoided,
as it causes sympathetic hyperactivity, increased
pulmonary vascular resistance, and interferes when
FiO2 requirement is increased7. It also causes an increase
in cerebral blood flow, which is of concern in patients
with raised ICP. Metabolic acidosis in this patient was
possibly because of decreased systemic blood flow
in the preoperative period, despite adequate efforts to
maintain PVR and SVR, intraoperatively. Additional
anesthetic issues include avoidance of air bubbles in
intravenous lines to prevent paradoxical air embolism.
To conclude, we successfully managed a patient of
aqueductal stenosis and hydrocephalus with associated
double aortic arch, PDA, and ASD, who underwent VP
shunt surgery. A detailed history and complete physical
examination along with an adequate investigational
work up would help in formulating anesthesia plan in
such patients.
M.E.J. ANESTH 20 (2), 2009
312
Mandeep Singh ET. AL
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aortic arch presenting as massive haematemesis after removal of a
nasogastric tube. Can. J. Anaesth; 1992, 39:894.
2. Papadopoulou E, Sifakis S, Rogalidou M, Makrigiannakis A,
Giannakopoulou C, Peterson MB: 3C syndrome with cryptorchidism
and posterior embryotoxon. Clin. Dysmorphol; 2005, 14:97-100.
3. Descipio C, Schneider L, Young TL, Wasserman N, Yaeger
D, Wheeler PG, Williams MS, Bason L, Jufosky L, Menon
A, Geschwindt R, Chudley AE, Saraiya J, Schinzel AA,
Guichet A, Dobysns WE, Toutain A, Spinner NB, Krantz ID:
Subteloremic deletions of chromosome 6p: molecular and cytogenic
characteristization of three new cases with phenotypic overlap
with Ritscher-Schinzel (3C) syndrome. Am. J. Med. Genet; 2005,
A.134:3-11.
4. Nijveldt R, Germans T, Beek AM, Gotte MJ, van Rossum AC:
Double aortic arch. Neth. Heart. J; 2007, 15:229-30.
5. van Son JA, Julsrud PR, Hagler DJ, Sim EK, Puga FJ, Schaff HV,
Danielson GK: Imaging strategies for vascular rings. Ann. Thorac.
Surg; 1994, 57:604-10.
6. Bent ST: Anesthesia for left-to-right shunt lesions. In: Andropoulos
DB, Stayer SA, Russell IA (ed). Anesthesia for congenital heart
disease; 2005, Blackwell Publishing Inc, Oxford.
7. Schulte-Sasse U, Hess W, Tarnow J: Pulmonary vascular responses
to nitrous oxide in patients with normal and high pulmonary vascular
resistance. Anesthesiology; 1982, 57:9-13.
ANESTHESIA FOR NELSON’S
SYNDROME
- Case Report -
Madhur Mehta*, Girija P Rath**
and G yaninder Pal S ingh *
Introduction
Adrenalectomy in the setting of residual corticotrope adenoma tissue predisposes to the
development of Nelson’s syndrome1; a disorder characterized by rapid pituitary tumour enlargement
and increased pigmentation secondary to high ACTH levels. We present the perioperative course of
a child with Nelson’s syndrome who underwent sublabial trans-sphenoidal hypophysectomy.
Case Report
A 12 yr-old, 30 kg female child was admitted with history of bilateral adrenalectomy for
Cushing’s syndrome 3 years back, following which she developed severe darkening of skin all
over body and gradually progressing headache. Her endocrine profile revealed ACTH levels of
220 pg/mL (Normal = 6-76 pg/mL) with cortisol of 1.2 µg/dL (normal = 5-25 µg/dL) for which
prednisolone 5 mg and fludrocortisone 50 µg daily were being supplemented. Growth hormone
levels were increased (4 ng/mL; normal <2 ng/mL). Well defined hypointense mass (9 × 3 mm)
arising from anterior pituitary was evident in CT scan. A diagnosis of Nelson’s syndrome was made
and sublabial transsphenoidal hypophysectomy was planned. Child was rendered euthyroid on
eltroxin 50 µg daily. Airway examination revealed coarse facies with Mallampati II airway.
Anesthesia was induced with propofol and fentanyl. Tracheal intubation was facilitated with
rocuronium. Maintainanence of anesthesia was done with isoflurane and N2O in 40% O2 and
intermittent boluses of rocuronium and fentanyl. At end of procedure, neuromuscular blockade
was reversed and trachea extubated. Postoperative course was uneventful. Perioperative steroid
coverage comprised hydrocortisone 50 mg 8 hourly, started 1 day preoperatively till postoperative
day 1, when oral prednisolone 25 mg daily in divided doses was started, subsequently tapered over
next 2 days to scheduled preoperative dose. Normal skin colour was restored in 1-2 days, probably
indicating successful removal of microadenoma.
From Department of Neuroanaesthesiology, All India Institute of Medial Sciences, New Delhi, India.
*
MD, Senior Resident.
** MD, Assist. Prof.
Correspondence: Dr. Girija Prasad Rath, Assist. Prof., Department of Neuroanaesthesiology, Neurosciences Centre, All
India Institute of Medical Sciences, New Delhi-110029, India. Tel: 91-11-26588700-3474, Fax: 91-11-26568663.
313
M.E.J. ANESTH 20 (2), 2009
314
Discussion
The incidence of Nelson’s syndrome has been
variably reported to be between 8-38%2-4. Younger
age and pregnancy are possible associated risk
factors. Hyperpigmentation of skin, minimal sellar
changes or raised ACTH though suggestive, need
neuroradiological confirmation for definite diagnosis
of Nelson’s syndrome. The predominant cause of
morbidity is from local tumor extension or invasion.
Patients with this disorder become deeply pigmented
because of excess alpha melanocyte stimulating
hormone (a-MSH), a derivative of propiomelanocortin
(POMC), the precursor peptide for ACTH. There may
be loss of pituitary function because of compression or
replacement of normal pituitary tissue or compression
of structures adjacent to the pituitary fossa by the tumor.
Lateral extension of the tumor may result in invasion of
the cavernous sinuses and entrapment or compression of
the cranial nerves (III, IV, V and VI). Superior extension
of the tumor can lead to compression or invasion of
optic apparatus and or the hypothalamus. Headaches
are common, are probably due to stretching of the
dura of the diaphragma sellae by the tumor. Pituitary
adenomas exhibit widely variable endocrine profile.
Madhur Mehta ET. AL
Panhypopituitarism rather than hypercortisolism is
characteristic by virtue of compression of normal
anterior pituitary by the tumour. Cortisol deficiency is
likely particularly in setting of bilateral adrenalectomy.
Perioperative steroid coverage is indicated in patients
with low cortisol levels to prevent acute adrenal
insufficiency. Though clear guidelines for perioperative
glucocorticoid replacement in pituitary surgery exist5,
we found no such specific recommendations for
Nelson’s syndrome. We feel that patients with Nelson’s
syndrome may particularly need perioperative steroid
replacement in view of their compromised adrenal
functions, especially when cortisol levels are less than
3.6 µg/dL. Patients with Nelson’s syndrome may be
asymptomatic for long periods with only presentation
being hyperpigmentation of skin. Hyperpigmentation
in addition to thick, oily and hyperhydrotic skin
may pose problems in securing intravenous line and
tracheal tube. Though our patient had increased growth
hormones and coarse facies, we did not encounter any
acromegalic features of the airway. Recovery of normal
skin colour may be an early indicator of successful
surgery; however the results need to be confirmed by
regular clinical and neuroradiological follow ups.
References
1. Nelson DH, Meakin JW, Dealy JB Jr, Matson DD, Emerson K Jr,
Thorn JW: ACTH-producing tumor of the pituitary gland. N Engl J
Med; 1958, 259:161-4.
2. Moore TJ, Dluhy RG, Williams GH, Cain JP: Nelson’s syndrome:
frequency, prognosis, and effect of prior pituitary irradiation. Ann
Intern Med; 1976, 85:731-4.
3. Cohen KL, Noth RH, Pechinski T: Incidence of pituitary tumors
following adrenalectomy. Arch Intern Med; 1978, 138:575-9.
4. Nagesser SK, Van Seters AP, Kievit J, Hermans J, Krans HM, Van
De Velde CJ: Long term results of total adrenalectomy for cushing’s
disease. World J Surg; 2000, 24:08-13.
5. Inder WJ, Hunt PJ: Glucocorticoid replacement in pituitary
surgery: Guidelines for perioperative assessment and management.
J Endocrinol Metab; 2002, 87:2745-50.
SUDDEN CARDIAC ARREST DURING
CESAREAN SECTION
- A Possible Case of Amniotic Fluid Embolism - Case Report -
Nikooseresht Mahshid*, Sadegian Ahmad**,
Manochehrian Nahid* and Farhanchi Afshin*
Abstract
Amniotic Fluid Embolism (AFE) is a rare obstetric catastrophe that occurs in approximately
1/50,000 pregnancies and has a mortality rate in excess of 80%. AFE is a condition that is poorly
understood and often difficult to diagnose. We report a case of a healthy 27 yr-old gravid two,
35 wk gestation parturient with a previous Cesarean section two years previously, and presently
admitted for emergent Cesarean section due to premature uterine contractions.
Induction of general anesthesias was performed with no problem and a male preterm infant
with Apgar 8 at 1min was delivered. Amniotic fluid was bloody and 40% placental abruption
existed. Following delivery of the placenta, patient suddenly became plethoric and O2 saturation
began to decrease and no pulse could be palpated! Immediate CPR was successful but she was
hemodynamically unstable and signs of right heart strain was obvious. Right jugular venous
catheterization was performed, vasopressors were administered. After a two hours period of
relatively stable vital signs, patient’s reflexes returned to normal, however, profound coagulopathy
on lab data was reported and she was treated with 10 unit Packed Red Blood Cells (PRBCs), 10
unit FFP and 8 unit platelets, Sodium bicarbonate, oxytocin and Methergine. The patient remained
hemodynamically unstable while laparotomy-hysterectomy was performed to stop the bleeding.
Unfortunately attempts were unsuccessful and patient died four hours later in ICU. Post-mortem
findings showed signs of Disseminated Intravascular Coagulation (DIC), no fetal squamous cells
in pulmonary vasculature were found and special staining of Cytokeratin marker shows no positive
cells in lumen of vessels.
The post-mortem diagnosis of AFE is challenging to forensic investigators and pathologists
and can be confirmed by histological confirmation of amniotic fluid contents in the pulmonary
vasculature, although they may be difficult to identify. In recent years it has been suggested that AFE
is an anaphylactoid reaction to fetal antigens and an elevated serum tryptase level is increasingly
being used to support the diagnosis.
Sudden onset of cardiovascular collapse and early signs of right heart strain and fulminant
DIC supports the diagnosis of AFE in this case, although no fetal debri could be find in pathologic
staining.
From Department of Anesthesiology and Intensive Care, Hamadan University of Medical Sciences, Hamadan, Iran.
*
MD, Assist. Prof.
** MD, Department of Pathology, Atieh Hospital, Hamadan, Iran.
Address correspondence to: Dr. M Nikooseresht, Assist. Prof., Department of Anesthesiology and Intensive Care, Hamadan
University of Medical Sciences, Fatemieh Hospital, Hamadan, Iran. Tel: +98 9123205754,
315
M.E.J. ANESTH 20 (2), 2009
316
Introduction
Amniotic Fluid Embolism (AFE) is a rare
catastrophic complication of pregnancy1. with an
incidence of approximately 1/50,000 pregnancies and
a mortality rate in excess of 80%1,2. The syndrome was
first reported in 1941 with the clinical and pathologic
features of eight woman who died because of sudden
shock during labour1.
Following rupture of membranes, powerful
uterine contractions may force amniotic fluid into the
uterine veins, usually with the partial detachment of
placenta. The amniotic fluid that contains epithelial
squamous, lanugos’ hairs, fat, mucus and meconium,
enters into the maternal circulation and causes
dyspnea, cor pulmonale, disseminated intravascular
coagulation, cardiovascular collapse and often death3
or permanent neurologic damage in most survivors4.
AFE is condition that is poorly understood and often
difficult to diagnose5. A definitive diagnosis of AFE
cannot be made until ancillary studies are performed
on the decedents tissue1,5.
Case Report
A healthy 27 yr-old gravid 2, 35 wk gestation
parturient with history of Cesarean section two years
previously, who was admitted for emergent Cesarean
section due to premature uterine contractions. Her
last sonography, two days previously, showed a hypo
echoic region behind placenta as she had fallen down
the stairs on the morning of the surgery.
Rapid sequence induction of general anesthesia
was performed with 350mg thiopental and 100mg
succinylcholine, the trachea was intubated and
auscultation of lung sounds were normal bilaterally..
A male preterm infant with Apgar 8 at 1min was
delivered. Amniotic fluid was bloody and 40%
placental abruption existed. After delivery of the
placenta, the patient suddenly became plethoric, and
O2 saturation began to fall, no pulse could be palpated!
Immediate CPR was successful and patients rhythm
returned to normal. Few minutes later, ventricular
fibrillation occurred, but after giving three 360J shocks
and epinephrine administration, rhythm returned to
normal but was hemodynamically unstable. A 12 lead
ECG showed signs of right heart strain.
Nikooseresht Mahshid ET. AL
Right jugular venous catheterization was
performed and infusion of dopamine 5μg/kg/min and
epinephrine 5 μg/min was started. She had relatively
stable vital signs for two hours and her reflexes (cough,
spontaneous ventilation, pain withdrawal…) returned
to normal. However, profuse vaginal bleeding was
observed and patient’s systolic blood pressure fell to
40 mmHg. Lab data reported metabolic acidosis and
profound coagulopathy on lab data were reported (PT
>2 min & PTT >3 min). She was treated with 10 units
of Packed Red Blood Cells (PRBCs), 10 unit FFPs
and 8 unit platelets, sodium bicarbonate, oxytocin and
methergine. The patient remained hemodynamically
unstable, in the meantime laparotomy-hysterectomy
was performed to stop the bleeding. Unfortunately
attempts were unsuccessful and patient died four hours
later in ICU.
Post-mortem findings showed signs of
Disseminated Intravascular Coagulation (DIC), no fetal
squamous cells in pulmonary vasculature were found
and special staining of Cytokeratin marker showed no
positive cells in lumen of vessels.
Discussion
Amniotic Fluid embolism (AFE) has been
reported during pregnancy, labour, Cesarean section
and the postpartum period. While the syndrome
remains poorly understood, it can be described as a
two-stage process. In the first stage, amniotic fluid and
fetal cells enter the maternal circulation, triggering the
release of several endogenous mediators. Pulmonary
artery vasospasm and pulmonary hypertension
lead to elevated right ventricular pressure, and the
resultant hypoxia causing myocardial and pulmonary
capillary damage5. Approximately half of all patients
who survive enter a second stage characterized by
hemorrhage and DIC, possibly because amniotic fluid
contains Thromboplastin6.
The post-mortem diagnosis of AFE is challenging
to forensic investigators and pathologists and can be
confirmed by histological confirmation of amniotic
fluid contents in the pulmonary vasculature of the
mother, although difficult to identify as some contests
are lodged in small pulmonary capillaries. Multiple
lung sections are submitted when diagnosing AFE
which increases the probability of finding elements of
SUDDEN CARDIAC ARREST DURING CESAREAN SECTION: A POSSIBLE CASE OF AMNIOTIC FLUID
EMBOLISM
amniotic fluid2,7. In recent years it has been suggested
that AFE is an anaphylactoid reaction to fetal antigens
and an elevated serum Tryptase level is increasingly
being used to support the diagnosis2,4,8,9.
In the absence of a definitive diagnostic test,
Benson proposed a clinically based definition of AFE.
According to his criteria, a diagnosis of AFE would
be appropriate for any patient experiencing sudden
onset of cardiovascular collapse during pregnancy or
317
48 hours postpartum. Other illnesses ought to ruled out
that might explain the signs and symptoms10.
The sudden onset of cardiovascular collapse in
this case preceded by plethoric discoloration of the
patients face suggests anaphylactoid reactions, and
early signs of right heart strain5 followed by progressive
fulminant DIC6, supports the diagnosis of AFE, though
no fetal debri could be found in the pathologic staining
of pulmonary vasculature.
References
1. Dudney T, Elliot CG: Pulmonary embolism from amniotic fluid, fat
and air. Prog Cardiovasc Dis; 1994, 36:447-474.
2. Marcus BJ, Collins K: Ancillary studies in Amniotic Fluid
Embolism: A case report and review of the literature. Am J Forensic
Med Pathol; 2005, 26(1):92-95.
3. Davies S. Amniotic fluid embolus: A review of the literature. Can J
Anesth; 2001, 48:88-98.
4. Aguilera LG, Fernandez C: Fatal Amniotic Fluid Embolism
diagnosed histologically. Acta Anesthesiol Scand; 2002, 46:334-7.
5. Schoening A, Misn RN: Amniotic Fluid Embolism: Historical
perspectives & new possibilities. Am J Mat Child Nurs; 2006,
31(2):78-83.
6. Gei A, Hankins G: Amniotic fluid embolus: an update. Contemp
Obstet Gynecol; 2000, 45:53-66.
7. Collings K, Hutchins G: Eds. Autopsy performance and reporting.
2nd ed. Illinois: College of American Pathologists, 2003, 139.
8. Farrar S, Gherman R: Serum Tryptase analysis in a woman with
amniotic fluid embolism: a case report. J Reprod med; 2001, 46:92628.
9. Randall B, Butts J, Halsey J: Elevated post-mortem Tryptase in
the absence of anaphylaxis. J Forensic Sci; 1995, 40:208-211.
10.Benson MD: Nonfatal amniotic fluid embolism: Three possible
cases and a new clinical definition. Archives Fam Med; 1993, 2:989994.
M.E.J. ANESTH 20 (2), 2009
PERIOPERATIVE CARE OF A CHILD WITH ULLRICH
CONGENITAL MUSCULAR DYSTROPHY
- Case Report -
Neesann Puangsuvan,BS , Robert A Mester,BS ,
Venkataraman Ramachandran,MD
and J oseph D Tobias , MD
1
1
3
2,4
*
Abstract
Ullrich congential muscular dystrophy (UCMD) is a severe form of congenital muscular
dystrophy manifesting axial muscle contractures and distal joint hyperlaxity. Severe hypotonia and
associated respiratory failure may occur early in the disease process. Given the various associated
orthopedic conditions, anesthetic management may be required during surgical interventions to
correct skeletal deformities or these patients may present with surgical conditions unrelated to
their primary illness. We present a 4-year-old with UCMD who required operative intervention for
a ruptured appendix. Anesthetic care implications included the need for a rapid airway control to
limit the risks of aspiration due to the intra-abdominal process, choice of neuromuscular blocking
agent for rapid sequence intubation, associated airway issues related to micrognathia and limited
mouth opening, and the potential for involvement of the cardiovascular and respiratory systems.
The perioperative management of patients with UCMD is discussed including the use of propofol
and remifentanil for rapid sequence intubation to avoid the need for neuromuscular blocking
agents.
Introduction
Ullrich’s congenital muscular dystrophy (UCMD) is a severe form of congenital muscular
dystrophy manifesting axial muscle contractures and distal joint hyperlaxity. It generally presents
as hypotonia at birth. The disorder was first described in 1930 by Otto Ullrich, who encountered
two children with proximal joint contractures and severe distal joint hyper-extensibility. He
subsequently named the disorder congenital atonic-sclerotic muscular dystrophy, but over the
years, it has become known as Ullrich’s congenital muscular dystrophy. UCMD is inherited as an
autosomal recessive trait although cases of spontaneous mutation have been described.
Other distinctive clinical features include a high-arched palate, protuberant calcanei, and
rigid spine syndrome. Despite the extensive muscular involvement, intelligence and development
are generally normal1. Early involvement of the diaphragm leads to early respiratory failure in
many patients as well as resulting in the predisposition to recurrent chest infections.
Affiliation: University of Missouri School of Medicine, Columbia, Missouri1 and the Departments of Anesthesiology2, Surgery3,
and Pediatrics4, University of Missouri, Columbia, Missouri, USA.
Address correspondence to: Joseph D Tobias, MD, Vice-Chairman, Department of Anesthesiology, Chief, Division of Pediatric
Anesthesiology, Russell and Mary Shelden Chair in Pediatric Intensive Care Medicine, Professor of Anesthesiology and
Child Health, University of Missouri, Department of Anesthesiology, 3W-27G HSC, One Hospital Drive, Columbia,
Missouri 65212. Phone: (573) 882-7168, Fax: (573) 882-2226. E-mail: [email protected]
319
M.E.J. ANESTH 20 (2), 2009
320
Given the various associated orthopedic
conditions, anesthetic management may be required
during surgical interventions to correct skeletal
deformities. Additionally, these patients may present
with surgical conditions unrelated to their primary
illness. We present a 4-year-old with UCMD who
required operative intervention for a ruptured appendix.
The perioperative management of such patients is
discussed.
Case Report
Review of this patient’s medical records and
presentation of this case report were approved by
the Institutional Review Board of the University of
Missouri. A 4-year-old, 14 kg girl presented with a
48 hour history of nausea, vomiting, and abdominal
pain. Computed tomography scan was suggestive
of appendicitis with rupture and she was scheduled
for an emergency laparoscopic appendectomy. The
patient’s past medical history was positive for UCMD
diagnosed by muscle biopsy at 19 months of age when
she presented with hypotonia and failure to achieve
developmental milestones. During her hospitalization,
the patient had been receiving morphine and ketorolac
for pain and antibiotic coverage with cefoxitin.
Physical examination revealed a well developed
child in moderate distress with complaints of
abdominal pain. Her vital signs were stable with no
evidence of respiratory distress. Airway examination
revealed micrognathia with a thyromental distance
of less than 2 centimeters and microstomia with a
mouth opening of 1.5 centimeters between the upper
and lower central incisors. The lungs were clear and
cardiac auscultation was unremarkable. Neurological
examination revealed mild hypotonia with strength of
4/5 in all 4 extremities. An intravenous cannula was
present in the right antecubital space and flowed easily
by gravity. Ranitidine (0.5 mg/kg) and metoclopramide
(0.1 mg/kg) were administered intravenously.
Premedication included midazolam (0.07 mg/
kg) and glycopyrrolate (5 µg/kg) intravenously and
the patient was transported to the operating room
where routine monitors were placed. The patient was
preoxygenated for 3 minutes with 100% oxygen and
this was followed by the administration of propofol (3
mg/kg) and remifentanil (3 µg/kg) for rapid sequence
N. Puangsuvan ET. AL
intubation with cricoid pressure. The first attempt at
laryngoscopy with a MacIntosh 2 blade was difficult
due to the microstomia and limited mouth opening.
This attempt at laryngoscopy was aborted and while
cricoid pressure was maintained, a second attempt
at laryngoscopy with a Wis-Hipple 1.5 laryngoscope
revealed a short epiglottis with a grade II view of the
airway. The patient’s trachea was intubated with a 5.0
mm uncuffed ETT. Maintenance of anesthesia consisted
of desflurane (expired concentration 4-8%) in 50% air/
oxygen supplemented with fentanyl (total of 3 µg/kg).
No neuromuscular blocking agents were administered.
The laparoscopic procedure was completed without
difficulty in approximately 75 minutes.
After completion of the procedure, a caudal
epidural block was performed with 1.2 mL/kg of
0.25% bupivacaine with 1 µg/kg of clonidine. She
was transported to the post-anesthesia care unit.
No supplemental pain medication was required for
the initial 10 postoperative hours. Subsequently,
pain was easily controlled with ketorolac (0.5 mg/
kg) administered every 6 hours around the clock,
supplemented with as needed doses of nalbuphine
(0.05 mg/kg). The remainder of her postoperative
course was uneventful.
Discussion
The congenital muscular dystrophies are
comprised of a heterogeneous group of diseases
affecting muscular architecture including Ullrich
congenital muscular dystrophy (UCMD), merosindeficient congenital muscular dystrophy, and rigid
spine syndrome. The congenital muscular dystrophies
present similarly during infancy and the neonatal period
with decreased intrauterine movement, hypotonia,
and delays in the achievement of motor milestones.
However, there are specific signs and symptoms which
may suggest the diagnosis of UCMD including spinal
rigidity, hyperlaxity of the joints of the hands and feet,
and early diaphragmatic involvement with chronic
respiratory infections or respiratory failure.
Biochemically, collagen type VI is a large,
ubiqitious, extracellular matrix protein which forms
a highly branched, microfilbrillar network of the
skeletal muscle providing structural support including
cell-to-cell adhesions and stability. Interactions have
PERIOPERATIVE CARE OF A CHILD WITH ULLRICH CONGENITAL MUSCULAR DYSTROPHY
been described between collagen type VI and the
major constituent of the muscle basement membrane,
collagen type IV indicating that it functions as an
anchor for the basement membrane to underlying
connective tissue2,3. Likewise, a variety of other matrix
components have been shown to interact with collagen
type VI particularly proteoglycans and other types of
collagen to form structurally critical cellular networks
for skeletal muscle3,4. The interactions between
proteoglycans such as chondroitin sulfate, biglycan,
and decorin and collagen VI provides important
mechanisms for transmembrane signaling in a variety
of tissues including: skeletal muscle, blood vessels,
and cartilagenous tissues throughout the body4-6. These
molecular interactions aid in cellular maintenance of
homeostasis as well as processes of wound healing
through interactions with fibronectin microfibrillar
networks4-6.
Structurally, collagen type VI is composed of
3 separate α-chains which are encoded by 3 separate
genes located on chromosomes 2 and 21. Mutations
in these genes result in 2 specific types of muscular
dystrophies including Bethlem myopathy and UCMD2.
Although Bethlem myopathy is generally a more
benign disease with a more variable onset and a slower
progression, UCMD presents in the neonatal period
with severe wasting of the axial musculature and
distal joint hyperlaxity. Of significant importance to
the perioperative care of these patients is the frequent
early involvement of the diaphragmatic musculature
which may progress to early and severe respiratory
failure. However, there remains significant interpatient
variability depending on the severity of the mutations
in the collagen VI gene resulting in a wide range of
clinical presentations and manifestations. These can
range from as mild as scoliosis or abnormal scar
formation and wound healing to neonatal hypotonia
with failure to achieve independent ambulation and an
early requirement for ventilatory support.
In our patient, anesthetic considerations included
not only her primary disease process, but also the need
to secure the airway using rapid sequence intubation
due to the presence of an intra-abdominal process
with delayed gastric emptying and the associated risk
for aspiration. In an effort to avoid the potential for
aspiration during anesthetic induction, we pretreated
321
our patient with an H2-antagonist and the motility
agent metoclopramide, followed by rapid sequence
intubation with cricoid pressure. Of primary concern
in such patients is the choice of medications to
allow for the rapid accomplishment of endotracheal
intubation. Given the risks of rhabdomyolysis,
hyperkalemia and cardiac arrest with succinylcholine,
this agent is absolutely contraindicated in patients with
muscular dystrophies7,8. Conversely, non-depolarizing
neuromuscular blocking agents (NMBA’s) are
considered safe in patients with various muscular
dystrophies. However, even with intermediate-acting
agents such as atracurium or vecuronium, doses which
are normally used for endotracheal intubation can
result in a prolonged duration of action as increased
sensitivity to these agents has been established in
patients with muscular dystrophies9,10.
Prior to their withdrawal, rapacuronium and
mivacurium, two short-acting NMBA’s, could have
been considered in this scenario although rapacuronium
may have been preferred given its rapid onset.
Frankowski et al. reported their experience with the
use of rapacuronium in 2 patients (9-years of age and
10-years of age) with Duchenne muscular dystrophy11.
There was a prolonged clinical duration (return of T1
to 25% of its baseline, (16.4 and 18.4 minutes vs. 13.8
± 7.2 minutes in the general population), a doubling of
the recovery index, and doubling of the spontaneous
recovery time (return of T4/T1 to ≥ 70%). Mivacurium
has also been suggested as a possible agent in patients
with muscular dystrophy12. In a cohort of 7 patients
with Duchenne muscular dystrophy, a dose of 0.2
mg/kg resulted in complete suppression of all four
twitches of the train-of-four in 1.5 to 2.6 minutes.
Time to recovery of the first twitch varied from 12 to
18 minutes.
Given that these short-acting neuromuscular
blocking agents are no longer available, we chose
to use an alternative technique of rapid sequence
intubation without a neuromuscular blocking agent.
Several investigators have reported the successful
use of a combination of remifentanil and propofol to
allow for endotracheal intubation without the need
for neuromuscular blocking agents13-16. Batra et al.
reported that propofol (3 mg/kg) and remifentanil (3 µ/
kg) could be used to allow for endotracheal intubation
M.E.J. ANESTH 20 (2), 2009
322
within 90 seconds without the use of a NMBA in
children ranging in age from 5 to 10 years13. Similar
efficacy has been reported in a cohort of adult patients
when using propofol (2 mg/kg) and remifentanil (3
µg/kg)14. In adult patients, Alexander et al. evaluated
the suitability of tracheal intubation 60 seconds
following the administration of propofol (2 mg/kg) and
remifentanil in doses ranging from 2 to 5 μg/kg. Good
or excellent conditions were present in 95% of patients
who received 4 µg/kg of remifentanil versus only 60%
of those who received 3 µg/kg.
In our patient, the combination of propofol (3
mg/kg) and remifentanil (3 µg/kg) produced excellent
conditions within 60-90 seconds although a second
attempt at laryngoscopy was necessary due to our
patient’s airway abnormality and the need to use a
direct laryngoscope blade.
Although anecdotal, previous reports exist
regarding the potential for difficulties with airway
management in patients with various muscular
dystrophies including both Duchenne and EmeryDreifuss variants17,18. As with our case, these
difficulties resulted from the combination of limited
mouth opening and restricted flexion/extension of the
neck. These issues are likely related to fibrotic changes
in the associated muscle groups including the masseter
muscles which may limit mouth opening. Furthermore,
in these cases reports and our patient, associated
micrognathia and a short thyromental distance further
complicated airway management. It remains unknown
whether these issues are sporadic occurrences or
somehow related to the muscle dystrophy.
In addition to the concerns outlined above
regarding rapid sequence intubation and airway
management, the underlying muscular dystrophy may
also predispose these patients to both respiratory and
cardiac problems. Of particular importance would
be the risk of postoperative respiratory failure. The
effects of residual anesthetic agents combined with
poor muscular function may predispose these patients
to upper airway obstruction. Poor cough reflex, preexisting muscle weakness, and diaphragm impairment
may further increase the risk for postoperative
atelectasis and respiratory failure. Although our
N. Puangsuvan ET. AL
patient underwent a laparoscopic, we chose to
place a caudal epidural block at the completion
of the procedure to ensure adequate postoperative
analgesia19. Supplemental postoperative analgesia was
then easily achieved with a combination of ketorolac
and nalbuphine thereby avoiding the need for strong
opioids and their potential for associated adverse
effects. We would suggest that use of a regional
anesthetic technique with a combination of local
anesthetic and clonidine may be beneficial in patients
with UCMD by eliminating the deleterious physiologic
effects of pain as well as avoiding the need for agents
which may potentially impair respiratory function.
Possible cardiac involvement posed an additional
anesthetic concern in our patient. Although commonly
associated with Duchenne and Becker muscular
dystrophy, there does not seem to be a strong association
between cardiac involvement and UCMD. Brockington
et al. reviewed a case series of fifteen patients with
UCMD patients. Both cardiac functional and electrical
conduction were examined with echocardiogram and
serial electrocardiograms. The entire study group
had an unremarkable echocardiogram and all but one
patient had normal electrocardiograms. Despite these
findings, the possibility of cardiac involvement is
raised by one child of the cohort who died suddenly
from an arrhythmia1.
In conclusion, we present a 4-year-old with
UCMD who required operative intervention for a
ruptured appendix. Anesthetic care implications
included the need for a rapid airway control to limit
the risks of aspiration due to the intra-abdominal
process, choice of neuromuscular blocking agent for
rapid sequence intubation, associated airway issues
related to micrognathia and limited mouth opening,
and the potential for involvement of the cardiovascular
and respiratory systems. The use of propofol and
remifentanil for rapid sequence intubation eliminated
the need for neuromuscular blocking agents. However,
some potential issues with airway management were
noted including micrognathia and limited mouth
opening. Additional involvement of respiratory
or cardiovascular performance may impact the
perioperative care of these patients
PERIOPERATIVE CARE OF A CHILD WITH ULLRICH CONGENITAL MUSCULAR DYSTROPHY
323
References
1. Brockington M, Brown SC, Feng L, et al: Collagen VI involvement
in Ullrich syndrome: a clinical genetic, and immunohistochemical
study. Neurology; 2002, 58:1354-9.
2. Lampe AK, Bushby KMD: Collagen VI related muscle disorders. J
Med Gen; 2005, 42;673-685.
3. Kuo HJ, Maslen CL, Keene DR, Glanville RW: Type VI Collagen
anchors endothelial basement membranes by interacting with type
IV collagen. J Bio Chem; 1997, 272:26522-26529.
4. Ruhl M, Sahin E, Johannsen M, et al: Soluble collagen VI drives
serum-starved fibroblasts through S-phase and prevents apoptosis
via down-regulation of Bax. J Biol Chem; 1999, 274:34361-8.
5. Ruhl M, Johannsen M, Atkinson J, et al: Soluble collagen VI
induces tyrosine phosphorylation of paxillin and focal adhesion
kinase and activates the MAP kinase erk2 in fibroblasts. Exp Cell
Res; 1999, 250:548-557.
6. Howell SJ, Doane KJ: Type VI collagen increases cell survival
and prevents anti-beta 1 integrin-mediated apoptosis. Exp Cell Res;
1998, 241:230-241.
7. Miller ED Jr, Sanders DB, Rowlingson JC, et al: Anesthesiainduced rhabdomyolysis in a patient with Duchenne muscular
dystrophy. Anesthesiology; 1978, 48:146-148.
8. Sethna NF, Rockoff MA, Worthern HM, et al: Anesthesia-related
complications in children with Duchenne muscular dystrophy.
9. Buzello W, Huttarsch H: Muscle relaxation in patients with
Duchenne’s muscular dystrophy. Br J Anaesth; 1988, 60:228-231.
10.Huang FY, Sun WZ, Wang KC, Pai SY: Increased sensitivity to
atracurium in a child with Duchenne’s muscular dystrophy. Anaesth
Sinica; 1990, 28:223-228.
11.Frankowski GA, Johnson JO, Tobias JD: Rapacuronium
administration to two children with Duchenne muscular dystrophy.
Anesth Analg; 2000, 91:27-28.
12.Tobias JD, Atwood R: Mivacurium in children with Duchenne
muscular dystrophy. Paediatr Anaesth; 1994, 4:57-60.
13.Batra YK, AL Qattan AR, Ali SS, et al: Assessment of tracheal
intubating conditions using remifentanil and propofol without
muscle relaxant. Pediatr Anesth; 2004, 14:452-456.
14.Stevens JB, Wheatley L: Tracheal intubation in ambulatory surgery
patients using remifentanil and propofol without muscle relaxants.
Anesth Analg; 1998, 86:45-49.
15.Alexander R, Olufolabi AJ, Booth J, et al: Dosing study of
remifentanil and propofol for tracheal intubation without the use
muscle relaxants. Anaesthesia; 1999, 54:1037-1040.
16.Politis GD, Tobias JD: Rapid sequence intubation without a
neuromuscular blocking agent in a 14-year-old female patient with
myasthenia gravis. Pediatr Anesth; 2007, 17:285-288.
17.Jones D, Cone A: Management of a difficult airway in a patient with
Duchenne’s muscular dystrophy. Br J Hosp Med; 1997, 58:410412.
18.Aldwinckle RJ, Carr AS: The anesthetic management of a patient
with Emery-Dreifuss muscular dystrophy for orthopedic surgery.
Can J Anesth; 2002, 49:467-470.
19.Tobias JD, Holcomb GW III, Brock JW III, et al: Analgesia
after inguinal herniorrhaphy with laparoscopic inspection of the
peritoneum in children. Am J Anesthesiol; 1995, 22:193-197.
M.E.J. ANESTH 20 (2), 2009
letters to the editor
PRACTICE GUIDELINES AND PREVENTION OF
OBSTETRIC ANESTHESIA-RELATED MATERNAL
MORTALITY
Krzysztof M. Kuczkowski*
In the United States obstetric anesthesia has been a major subspecialty of anesthesiology
for a long time and is now an integral part of practice of most anesthesiologists1. An obstetric
anesthesiologist has become an essential member of the obstetric care team, who closely works
with the obstetrician, family practitioner, midwife, neonatologist and Labor and Delivery nurse
to ensure the highest quality care for the pregnant woman and her baby. The anesthesiologist’s
(obstetric anesthesiologist’s) unique skills in acute resuscitation combined with experience in
critical care, make members of our specialty (subspecialty) particularly valuable in the peripartum
care of the high risk patients, extending our role well beyond the routine provision of intrapartum
anesthesia or analgesia1.
It is with interest that I read the recent, and timely article by Siddik-Sayyid and Zbeidy
discussing the practice guidelines for obstetric anesthesia. I wish to express my great appreciation
to the authors for their thoughtful and valuable comments, recommendations, and conclusions. I
also wish to add the following (brief) comments on this important subject.
1.
Anesthesia-related complications are the sixth leading cause of pregnancy-related maternal
mortality in the United States3. Difficult or failed intubation following induction of general
anesthesia for Cesarean delivery remains the major contributory factor to anesthesia-related
maternal complications. Although the use of general anesthesia has been declining in obstetric
patients, it may still be required in selected cases. Since difficult intubation in obstetric
anesthesia practice is frequently unexpected, careful and timely preanesthetic evaluation of
all pregnant women should identify the majority of patients with difficult airway and avoid
unexpected difficult airway management3,4.
From Departments of Anesthesiology and Obstetrics and Gynecology, Texas Tech University Health Sciences Center at El Paso,
El Paso, Texas, United States of America.
*
Krzysztof M Kuczkowski, MD, Associate Professor of Anesthesiology and Obstetrics and Gynecology, Vice-Chair for
Academic Affairs, Department of Anesthesiology, Chief, Obstetric Anesthesia Services, Director, Fellowship in Obstetric
Anesthesia.
Corresponding author: Krzysztof M. Kuczkowski, MD, Department of Anesthesiology, Texas Tech University Health
Sciences Center at El Paso, Paul L Foster School of Medicine, 4800 Alberta Avenue, El Paso, Texas, United States of
America. Phone: (858) 638-8168, Fax: (858) 638-8168. E-mail [email protected]
325
M.E.J. ANESTH 20 (2), 2009
326
2.
Krzysztof M. Kuczkowski
The American College of Obstetricians and
Gynecologists (ACOG) recognizes hazards of
general anesthesia (particularly if administered
in emergency situation), and recommends early
consultation with an obstetric anesthesiologist
in all high-risk parturients. Such early
communication should encourage timely decisionmaking and improve the cooperation between
the obstetricians and obstetric anesthesiologists.
ACOG also advocates early administration of
epidural analgesia in all high-risk parturients,
particularly the morbidly obese and those with a
potentially difficult airway5.
Keywords: Obstetric anesthesia, complications,
difficult airway, pregnancy, labor analgesia,
complications,
maternal
mortality,
maternal
morbidity.
References
1. Kuczkowski KM: New and challenging problems (and solutions) in
obstetric anesthesia: introduction. J Clin Anesth; 2003, 15:165.
2. Siddik-Sayyid S, Zbeidy R: Practice guidelines for obstetric
anesthesia-a summary. Middle East J Anesthesiol; 2008, 19:12911303.
3. Kuczkowski KM, Reisner LS, Benumof JL: Airway problems and
new solutions for the obstetric patient. J Clin Anesth; 2003, 15:552563.
4. Kuczkowski KM, Reisner LS, Benumof LJ: The Difficult Airway:
Risk, Prophylaxis and Management. In Chestnut DH (ed.). Obstetric
Anesthesia: Principles and Practice; 3rd Edition, Elsevier Mosby,
Philadelphia, PA, USA 2004, 35-561.
5. Committee on Obstetrics: Maternal and fetal medicine: Anesthesia
for emergency deliveries. Washington, DC, American College of
Obstetricians and Gynecologists Committee Opinion # 104. 1992.
TONGUE SWELLING IN A CHILD AFTER
CLEFT PALATE SURGERY
Kerem Erkalp, Zehra Yangın, Gokcen Basaranoglu,
Haluk Ozdemir, Yavuz Haspolat
and L eyla S aidoglu
**
Dear Editor;
Tongue swelling (TS) after surgery is a rare but potentially lethal postoperative complication1.
TS causes include trauma, allergy, infection, bleeding, massive fluid overload and rarely ischemia
and infarction of the tongue. In anesthesia practices, it is usually presented after long term oral
intubations2.
In this report we present TS case which started immediately after operation and lasted 20
hours in child who had undergone a cleft palate repair.
A 3 years-old, 13 kg girl; Non premedicated, after sevoflurane induction, succinylcholine
was administered. The trachea was intubated atraumatically, size 4 mm cuffed tracheal tube
(Mallincrot). Anesthetic maintenance was with sevoflurane in nitrous oxide/oxygen (50/50%).
After 155 minutes of uneventful cleft palate repair operation and trachea was extubated and
taken into postanesthesia care unit (PACU). The patient was observed to have developed TS 20
minutes postoperatively (Fig. 1). It was thought to have been caused by the tongue depressor and the
patient observed closely. Her hemodynamic status was normal, bilateral lung ventilation was good,
arterial saturation was satisfactory and there was no inspiratory stridor. No ventilation difficulty
developed. Methylprednisolon 20 mg was given intravenously. After 1 hour of observation in the
PACU no further enlargement and deterioriation was seen in the child and she was sent to reanimation
care unit for close follow-up. Intubation preparations was made up. The patient was observed with
Fig. 1
Tongue swelling after cleft
palate repair
From Department of Anesthesia and Reanimation. Vakıf Gureba Educational and Research Hospital, İstanbul, Turkey.
Corresponding Author: Kerem Erkalp, Şenlikköy Mah. Ekşinar Cad., İncir Sok, No:3, Sarı Konaklar Sitesi, Daire:6, Florya,
İstanbul, Turkey. E-mail: [email protected]
327
M.E.J. ANESTH 20 (2), 2009
328
her head up and oxygen was given via face mask. With
the help of her mother cold compression was applied
with cold sticks. After her uneventful follow-up, the
child's tongue regressed to its normal size and she was
sent to plastic surgery ward.
The congestion, caused by the deterioriation
of the venous drainage of the tongue lead to the
swelling of tongue. Cyanosis usually accompanies
swelling of the tongue if is an accompanying arterial
obstruction (ischemia, infarct) it. The tongue depressor
of the automatic ecartor which is used in cleft palate
Kerem Erkalp et. al
operations may have caused TS by the deterioration of
the venous circulation and may have lead to respiratory
difficulties and difficult airway3. In our case TS was
not complicated and remained limited, and because
of that the follow up was limited to observation and
symptomatic treatment. However, after that event we
searched the published literature and found that airway
patency and safety should be provided to the patients
who developed TS, and extubation should only be done
after resolving of the edema and the tongue regressed
to its normal size4.
References
1. Yamamoto H, Fujimura N, Namiki A: Swelling of the tongue after
intraoperative monitoring by transesophageal echocardiography.
Masui; 2001, 50 (11):1250-2 (Abstract).
2. Grigsby EJ, Lennon RL, Didier EP, et al: Massive tongue swelling
after uncomplicated general anaesthesia. Can J Anaesth; 1990,
37(7):825-6.
3. Tan WK, Liu EH, Thean HP: A clinical report about an unusual
occurence of post-anesthetic tongue swelling. J Prosthodont; 2001,
10(2):105-7.
4. Twigg S, Brown JM, Williams R: Swelling and cyanosis of the
tongue associated with use of a laryngeal mask airway. Anesth
Intensive Care; 2000, 28(4):449-50.
Requested Change
Dr. Mehdi Trifa, the Corresponding Author, requests a change in
the names of authors in the article:
THE ANALGESIC EFFECTS OF ILIOINGUINALILIOHYPOGASTRIC NERVE BLOCK IN CHILDREN –
Concentration or Volume?
Pulished in the Middle East Journal of Anesthesiology, Volume
20 (1), February 2009, page 83, to read as follows” TRIFA M,
CHAABANE Z, DRIDI S, SEBAI B, MISSAOUI A, FEKIH
HASSEN A AND BEN KHALIFA S
329
M.E.J. ANESTH 20 (2), 2009
GUIDELINES FOR AUTHORS
The Middle East of Anesthesiology publishes original
work in the fields of anesthesiology, intensive care, pain, and
emergency medicine. This includes clinical or laboratory
investigations, review articles, case reports and letters to the
Editor.
Submission of manuscripts:
The Middle East Journal of Anesthesiology accepts
electronic submission of manuscripts as an e-mail attachment
only.
Manuscripts must
attachment to:
be
submitted
via
email
Editor-In-Chief,
Department of Anesthesiology,
American University of Beirut Medical Center
Beirut, Lebanon
Human Subjects
Manuscripts describing investigations performed in
humans must state that the study was approved by the appropriate
Institutional Review Board and written informed consent was
obtained from all patients or parents of minors.
Language:
Articles are published in English.
Manuscript Preparation
Manuscript format required:
Double-spaced lines
Wide margins (1.5 inches or 3.8 cm)
Page numbers start on title page
Word count should reflect text only (excluding abstract,
references, figures and tables).
Editorial
1500
Abstract
250 (General articles)
100 (Case Reports)
Clinical or laboratory investigations:
The following structured format is required:
1. Cover Letter
7. Discussion
2. Title page
8. Acknowledgements
3. Abstract
9. References
4. Introduction
10. Tables
5. Methods
11. Figures
6. Results
1. Cover Letter
Manuscripts must be accompanied by a cover letter,
signed by all authors and stating that:
- All authors have contributed intellectually to the
manuscript and the manuscript has been read and
approved by all the authors.
- The manuscript has not been published, simultaneously
submitted or accepted for publication elsewhere.
2. Title Page
Starts at page 1 and includes:
- A concise and informative title (preferably less than 15
words). Authors should include all information in the
title that will make electronic retrieval of the article both
sensitive and specific.
- Authors listing: first name, middle initial and last name
with a superscript denoting the academic degrees as
footprints.
- The name of the department(s) and institutions(s) to
which the work should be attributed.
- The name, address, telephone, fax numbers and e-mail
address of the corresponding author.
- Disclose sources of financial support (grants, equipment,
drug etc…).
- Conflict of interest: disclosure of any financial
relationships between authors and commercial interests
with a vested interest in the outcome of the study.
- A running head, around 40 characters.
- Word count of the text only (excluding abstract,
acknowledgements, figure legends and references).
Review article
4000
Original article
3000
Case Reports
800
3. Abstract
Letter to Editor
500
Abstract should follow the title page. It should be
structured with background, methods, results and conclusion.
M.E.J. ANESTH 20 (2), 2009
It should state, the specific purpose of the research or
hypotheses tested by the study, basic procedures, main findings
and principal conclusions.
Provide separate word count for the abstract.
4. Introduction
Provide the nature of the problem and its significance.
State the specific purpose or research objectives or hypothesis
tested. Provide only directly pertinent references and do not
include data or conclusions from the work being reported.
5. Methods
A. Selection and description of participants:
- Describe selection of participants (including controls)
clearly, including eligibility and exclusion criteria.
B. Technical information:
- Identify the methods, apparatus (give the
manufacturer’s name and address in parentheses),
and procedure in sufficient detail to allow others
to reproduce the results. Give references to
established methods. Provide references and brief
descriptions for methods that have been published.
Identify precisely all drugs and chemicals used,
including generic names(s), dose(s) ands routes(s)
of administration.
C. Statistics-describe statistical methods with enough
detail to enable a knowledgeable reader with access to
the original date to verify the reported results. Define
statistical terms, abbreviations and most symbols.
Specify the computer software used. Provide a power
analysis for the study.
6. Results
Present your results in logical sequence in the text, tables
and illustrations, giving the main or most important findings
first. Do not repeat all the data in the tables or illustrations
in the text: emphasize or summarize only the most important
observations. Extra or supplementary materials and technical
details can be placed in an appendix.
7. Discussion
Emphasize the new and important findings of the study
and the conclusions that may be drawn.
Do not repeat in details data or other information given
in the Introduction or the Results sections. For experimental
studies, it is useful to begin the discussion by summarizing
briefly the main findings, then explore possible mechanisms or
explanations for these findings, compare and contrast the results
with other relevant studies. State the limitations of the study,
and explore the implications of the findings for future research
and for clinical practice. Link the conclusions with the goals of
the study, but avoid unjustified statements and conclusions not
adequately supported by the data.
8. Acknowledgements
They should be brief. Individuals named must be given
the opportunity to read the paper and approve their inclusion in
the acknowledgments.
9. References
- References should be indicated by Arabic numerals in
the text in the form of superscript and listed at the end
of the paper in the order of their appearance. Please be
accurate, giving the names of all authors and initials, the
exact title, the correct abbreviation of the journal, year of
publication, volume number and page numbers.
- The titles of journals should be abbreviated according
to the style used in the list of Journals Indexed for
MEDLINE.
Example: (1) from a journal (2) from a book.
1. SHAWW: AND ROOT B: Brachial plexus anesthesia
Comparatives study of agents and techniques. Am. J.
Surg.; 1951, 81:407.
2. ROBINSON JS: Modern Trends in Anaesthesia, Evans
and Gray Ch. 8, Butterworth Pub. Co., London 1967.
10. Tables
Tables capture information concisely and display it
efficiently: They also provide information at any desired level
of details and precision. Including data in tables rather than text
frequently makes it possible to reduce the length of the text.
- Type or print each table with double spacing on a separate
sheet of paper.
- Number tables consecutively in the order of their first
citation in the text.
- Supply a brief title for each.
- Place explanatory matter in footnotes, not in the
heading.
- Explain all nonstandard abbreviations in footnotes.
- Identify statistical measures of variations, such as
standard deviation and standard error of the mean.
11. Figures
- Figures should be submitted in JPEG or TIFF format
with a minimum of 150 DPI in resolution.
- Colored data if requested by author is chargeable.
- If a figure has been published previously, acknowledge
the original source and submit written permission from
the copyrights holder to produce the figure.
Abbreviations and symbols:
- Use only standard abbreviations.
- Avoid abbreviations in the title of the manuscript.
- The spelled-out abbreviations followed by the
abbreviation in parenthesis should be used in first
mention.
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