The Principles, Technique, and Complications

CARDIOPULMONARY BYPASS
The P rinciples,
Technique, and
Com plications
Dr. Saswata Deb, MD, BSc Hon
Resident, Cardiac Surgery
Mazankowski Alberta Heart Institute
University of Alberta
Objectives
1
History of CPB
2
Physiological Principles of CPB
3
Components and Technique of CPB
4
Complications
History of CPB
•
•
Dr.Gibbons, inventor of the Heart & Lung machine
– Also known as, cardio-pulmonary bypass
machine (CPB)
1930 – mentor Dr.Churchill, did a pulmonary
embolectomy on a female patient
– Embolus removed, patient died
– “It was then that I found myself thinking how we could have
Dr. John H. Gibbons Jr.
helped her if we only had had some way of taking out the blue
venous blood, getting oxygen into it while carbon dioxide
escaped, and then putting the blood back into the arterial
system.
•
•
”
1935 – maintained a cat’s circulation on CPB while
closing the pulmonary artery
1936 – teamed with IBM president Thomas Watson
and a group of engineers
History of CPB
• 1953 – Cecelia Bavolek
– First patient to undergo
open heart surgery
using CPB to repair an
atrial septal defect
Dr. Gibbons & Cecelia Bavolek
...More than 40 years of Innovation,
Research, and Hard Work.....
Melrose
Cross
Rygg
Objectives
1
History of CPB
2
Principle of CPB
3
Components and Technique of CPB
4
Complications
Principle of CPB
• Deoxygenated blood
(Venous Return) 
taken away from the
body to the CPB
machine  pumped
and oxygenated 
returned back to the
body
Principles of CPB
• TEAM
– Surgeon
– Anesthetist
– Perfusionist
• Ultimately the surgeon is directly
responsible for patient outcome, but
for success, needs strong/open
communication between each team
member
The CPB Team
• Roles
– Surgeon
• Determines the planned operation, target
perfusion temperatures, methods of
quadriplegia, annulations
• Communicates procedural steps
– Connecting/disconnecting CPB, perfusion
management, surgical exposure
– Perfusionist
• Setting up and priming the CPB machine,
safety checks, monitoring anticoagulation,
adding prescribed drugs, maintaining records
– Anesthetist
• Anesthesia
• “Troubleshooter” of complex procedures along
with the surgeon
Objectives
1
History of CPB
2
Principle of CPB
3
Components and Technique of CPB
4
Complications
Components of CPB
•
•
•
•
•
•
•
•
•
Venous and arterial cannulas
Venous Reservoir
Centrifugal pump
Oxygenator, heat exchanger , venous
reservoir
Microfilter bubble trap on the arterial side
Suction systems
– Aspirate blood  cardiotomy
reservoir and filter  returns to
venous reservoir
– Field blood  washed in a cell
saver system  returned as pRBCs
Partial and occluding clamps to direct and
regulate flow
Various ports in the system to obtain
blood samples, sensors for monitoring
pressures, temperatures, O2 sats, blood
gases
Cardioplegic system, LV Vent
The Complete CPB Circuit
Venous Drainage and Cannulation
• Venous Drainage
– Drains into circuit through venous cannula
– Enters circuit by gravity or siphonage into
venous reservoir 40-70cm below level of
heart
– Amount of drainage determined by:
• CVP, height differential, resistance in
cannulas, tubing and connectors, absence of
SI PHON
air in the system
Venous Drainage and
Cannulation
•
Venous Cannulation
•
3 basic approaches
– Venous cannulas – usually made of
flexible plastic
– Size determined by patient size,
anticipated flow rate, flow
characteristics and resistance
• Usually 30F in SVC and 34F in IVC or
a single 42F
– Bicaval, single atrial, cavoatrial (2-stage
Cannula)
• 2-stage cannulas (Usual choice)
cathether in right atrial appendage
• Narrowed distal end into IVC while
wider proximal portion has side holes
designed to rest within RA
• More stable and provides better
drainage than single cannula
A: Bicaval
B: 2-stage Cannula
Augmented / Assisted Venous Return
• Negative pressure can be applied using
roller pump, centrifugal pump or regulated
vacuum
– Augmented negative pressure increases
risk of aspirating air  cerebral injury &
hemolysis
• Positive pressure in venous reservoir  air
can enter venous lines and right heart
• Therefore, must carefully analyze and reevaluate lines and monitors
Complications of Venous drainage
•
•
•
•
•
•
Arrhythmias
Atrial or caval tears
Bleeding
Air embolization
Unexpected decanulation
Caval tapes may displace CV or PA
monitor catheters
• Improperly placed pure-string sutures may
obstruct cava when tied
Arterial Cannulation
Arterial
Cannulation
Aortic
Axillary
Femoral
Ascending Aortic
Cannulation
• Tip of arterial cannula narrowest part of the perfusion
system
• Distal ascending aorta is preferred due to ease of
placement and fewest complications
• Usually 2 sutures (full or partial thickness) through aortic
wall placed
• 4-5mm full thickness stab wound made
• Cannula inserted under a finger with MAP of 6080mmHg
– Cannula inserted 1-2cm with some back bleeding,
rotated to ensure that it is in lumen, and positioned to
direct flow to the mid-transverse aorta
• Proper placement confirmed by noting non-pulsatile
pressure in aortic line monitor
• Once in place, cannula MUST be secured in place
Complications of AA Cannulation
•
•
•
•
Difficult insertion, bleeding, tear in aortic wall, intramural or
malposition of cannula tip, air emboli, plaque emboli, aortic
dissection
Atherosclerosis of the ascending aorta
– Dislodgement of plaque/debris from wall manipulation/Xclamping/or sand-blasting effect of the cannula jet = Major
cause of Peri-operative Stroke
Majority of surgeons use simple palpation but epiaortic scanning is
ideal
Epiaortic scanning indicated for:
– Hx of TIA, CVA, severe PVD, palpable aortic calcification,
calcified aortic knob on CXR
Complications of AA
Canulation
• Aortic dissection
– 0.01-0.09% of aortic cannulations
– Common in aortic root disease
– First SSx – discoloration beneath adventia near
cannula site, increase in art line pressure, sharp
reduction in return to venous reservoir
• Emergency Management:
– Transfer cannula to a peripheral artery or
uninvolved distal aorta
– Control BP pharmacologically
– Decrease perfusate temperature to < 20 ºC
– Circulatory arrest and repair aorta
Femoral Cannulation
• First alternative to aortic cannulation
• Indicated for initiating CPB quickly, cardiac
arrest, acute intraop dissection, limited
access
– Complications:
• Retrograde arterial dissection (0.21.3%)
– MOST SERIOUS with 50% mortality
• Tears, late stenosis, thrombosis,
bleeding, lymph fistula, infection in
groin, cerebral or coronary
atheroembolism
Axillary Cannulation
• Increasing use
• Aortic surgery, circulatory arrest cases
• Advantage:
– Freedom from atherosclerosis, antegrade
flow into arch vessels, protection of arm
and hand by collateral flow
• Disadvantage:
– Risk of brachial plexus injury, axillary artery
thrombosis
Components of CPB
•
•
•
•
•
•
•
•
•
•
Venous and arterial cannulas
Venous Reservoir
Centrifugal pump
Oxygenator, heat exchanger , venous
reservoir
Microfilter bubble trap on the arterial side
Suction systems
– Aspirate blood  cardiotomy reservoir
and filter  returns to venous reservoir
– Field blood  washed in a cell saver
system  returned as pRBCs
Partial and occluding clamps to direct and
regulate flow
Various ports in the system to obtain blood
samples, sensors for monitoring pressures,
temperatures, O2 sats, blood gases
Cardioplegic system
LV Vent
Venous Reservoir
Venous Reservoir
• Placed immediately before arterial pump
• Reservoir is high capacitance (low
pressure) receiving chamber for Venous
Return
• Facilitates gravity drainage
• Can add drugs, fluids, or blood
– Can hold 1-3L of blood when patient on full
CPB
Venous Reservoir
Hard-Open
Rigid Plastic
Canisters
•(+) – facilitate
measurements
•-easier to prime
•-larger capacity
•Easier mgt of
venous air
•(-) – higher risk
of micro-emboli
d/t silicon
SoftClosed
Venous Return
Reservoirs
Collapsible
Plastic
Bags
•Eliminate
Blood-gas
interface
•Collapses 
reduce risk of
air emboli
Pumps
Pumps
• Most machines use 2 types of pumps
– Roller pump and Centrifugal pump
Pumps
• Centrifugal pump
– Used in the primary circuit
– Consist of nested plastic cones, rotated rapidly,
propel blood by centrifugal force
– Pumps with up to 900 mmHg forward pressure
and 400mmHg of backward pressure
• Forward pressure determined by speed of
rotation and afterload of the arterial line
– Can pump small amounts of air but become
deprimed if > than 50mL of air enters blood
chamber
– Produce pulseless blood flow
Pumps
• Roller Pumps
– Used for central pump, sucker systems
and for delivering cardioplegic solutions
– Length of polyvinyl silicone/latex tubing
compressed by 2 rollers 180 degrees apart
– Forward flow generated by roller
compression
– Flow rate dependent on tubing diameter,
rate of rotation, length of compression
raceway
– Produces a sine wave pulse blood flow at
5mmHg
• No evidence to produce pulsatile
perfusion during short/long-term CPB
Pump Comparison
Description
Advantages
Roller pump
Centrifugal pump
Nearly occlusive
Nonocclusive
Afterload independent
Afterload sensitive
Ease of use
Portable, position insensitive
Low cost
Safe positive and negative pressure
No potential for backflow
Adapts to venous return
Shallow sine-wave pulse
Superior for right or left heart bypass
Preferred for long-term bypass
Protects against massive air embolism
Disadvantages
Excessive positive and negative pressure
Large priming volume
Spallation
Requires flowmeter
Tubing rupture
Potential passive backward flow
Potential for massive air embolism
Higher cost
Necessary occlusion adjustments
Requires close supervision
Pump Complications
•
•
•
•
Loss of electricity
Loss of ability to control pump speed
Loss of flow meter or RPM indicator
Rupture of tubing in the roller pump
raceway
• Means to manually provide pumping in
case of electrical failure should always be
available
Heat Exchangers
Heat Exchangers
• Control body temperature
• Hypothermia often preferred
– Gasses more soluble in cold than warm blood
• Rapid rewarming may cause bubble emboli
• Heater is also placed upstream of oxygenator to prevent bubble
emboli
• Temperature difference between body and perfusate kept <10
• Temp kept < 40ºC to prevent denaturation of proteins
• Cardioplegia requires separate heat exchanger
• Simplest system is to use bags of precooled quadriplegia
solution and is circulated through a dedicated heat
exchanger/ice baths
Oxygenator
Oxygenator
• Membrane Oxygenators
– Imitates natural lung by providing a thin
membrane of either microporous polypropylene
or silicone rubber between the gas and blood
phases
– Plasma filled pores prevent gas from entering
blood but allows exchange of Oxygen and CO2
– O2 = poor diffusate in plasma
• Blood is spread as thin film over large area with
high differential gas pressures between
compartments
• Areas of turbulence enhance diffusion of oxygen
within blood
Oxygenator
Oxygenator
• Can produce upto 470mL of O2 and remove 350mL of CO2 / minute
at 1-7L of flow
• Other tools in the oxygenator include:
– Flow regulators, flow meters, gas blender, oxygen analyzer,
gas filter, moisture trap
• Malfunctioning of oxygenators occurs in 0.02-0.26% of cases
– Most common reason=development of abnormal resistant of
blood path in the oxygenator
• Heparin coating can help to reduce this
– Others include leaks, loss of gas supply, rupture of
connections, failure of the blender, and failure of gas
exchange
– Monitoring of blood gasses is very important to ensure
adequate removal of CO2 and oxygenation
Heparin Coated Circuits
• Can be attached to blood surfaces of all
components of the CPB through ionic and
covalent bonds
• Literature for need is controversial
– No credible evidence that heparin-coated
perfusion circuits reduce need for systemic
heparin, or reduce bleeding or thrombotic
problems associated with CPB
Cardiotomy Reservoir /
Field Suction
• Blood aspirated from surgical wound maybe
directed to cardiotomy reservoir
– Gets defoamed, filtered and added to perfusate
• Macro and microfilters are crucial
– Negative pressure for suction generated by roller
pump
– Suction = major sources of hemolysis, emboli,
platelet injury, thrombin generation, fibrinolysis
– Current reservoirs manufactured to reduce this
• Alternate option is cell saver
– Field aspirate blood is diluted with saline and saline
removed to return only pRBC to perfusate
Venting the Heart
• RV distention rarely a problem during cardiac
arrest
• LV distention is a problem
– Insidious
– Multiple sources of blood
• Escaping blood from the atrial or venous cannulas
• Blood from coronary sinus and the thebesian veins
pass into Pulmonary circulation
• Bronchial arterial and venous blood
• Blood from Aortic Valve regurgitation
• Unknown sources (PFO, PDA)
Left Heart Venting
• Commonly, multihole, soft-tip
catheter (8-10F) inserted into
RPSV and LA and into LV
• Vent connected to cardiotomy
reservoir
• Most common complication =
Residual air when heart
restarted and begins to fill
– De-airing maneuvers and
TEE important to ensure
removal
– Aspirate ascending aorta
via small metal or plastic
cannula
Cardioplegia System
Cardioplegia System
• Solution contains 8-20 MeQ/L of K+,
Mg++, and other components
• Given Anterograde and/or Retrograde
• Temp varies (4-37ºC)
– Normothermic  continuous
– Cold  intermittent
• Delivered through separate perfusion
system that includes a reservoir, heat
exchanger, roller pump and bubble trap
Filter and Bubble Traps
• Can generate gaseous, biologic and non-biologic
microemboli
– O2, N, thrombus, broken cells, atherosclerotic
debris, muscle debris, materials of the circuit
• Strategies of prevention
–
–
–
–
Reduce PCO2  cerebral vasoconstriction
Hypothermia
Placing cannulas downstream of cerebral vessels
Microfilters
• Depth and screen filters
– Depth – packed fibers or porous forms and removes
debris by absorption and impaction
– Screen filters – made of woven polyester or nylon
thread, defined pore size and filter by interception
Perfusion Monitors and Safety Devices
Device or procedure
Low venous blood level alarm
With pump cut-off
Usage (%)*
60–100
34–80
High arterial line pressure alarm
With pump cut-off
84–94
35–75
Macrobubble detector
With pump cut-off
42–88
62–63
Arterial line filter
44–99
Pre-bypass recirculation/filtration
75–81
Oxygen supply filter
81–95
In-line venous oxygen saturation
75–76
Batteries in heart-lung machine
29–85
Back-up arterial pump head
80
Back-up heater-cooler
97
Back-up oxygen supply
88–91
Emergency lighting
62–91
Pre-bypass activated clotting time
74–99
The CPB Team
• Roles
– Surgeon
• Determines the planned operation, target perfusion
temperatures, methods of quadriplegia, annulations
• Communicates procedural steps
– Connecting/disconnecting CPB, perfusion
management, surgical exposure
– Per fusionist
• Setting up and priming the CPB machine, safety
checks, monitoring anticoagulation, adding
prescribed drugs, maintaining records
– Anesthetist
• Anesthesia
• “Troubleshooter” of complex procedures along with
the surgeon
The Set-UP
•
•
•
•
Per fusionist responsible for setting up
Takes 10-15 minutes
Can be kept on stand-by for upto 7days
Takes 15min to prime with fluid, once
primed, must be used within 8 hours
Priming
• Adult circuits require 1.5-2L of balanced electrolyte solution
– RL, Normosol-A, or Plasma-Lyte
• Volume ~40% of patient’s blood volume
– ↓ HCT by 1/3 of pre-op value
• Sometimes banked blood added to raise HCT
• No consensus on optimal HCT
• Usually 20-25%
– Dilution may also ↓ O2 carrying capacity and ↓ MvO2 to
<60%
• If this occurs, need to transfuse or increase pump flow
• Sometimes, 12.5-50g of mannitol added to stimulate diuresis
minimize post-op renal dysfunction
• No evidence to support colloids in the priming volume
• Addition of Glucose/Lactate avoided because shown to
increase neurologic deficits
Anticoagulation
• 300 – 400 Units/Kg IV heparin given before arterial and
venous cannulation
• Porcine vs bovine
– Bovine more antigenic
– ↑ antiplatelet IgG antibodies
• Measure ACT 3 minutes after dose
– ACT >400 to begin
– If ACT not increasing
• May increase heparin dose to 500U/kg
• May need FFP (antithrombin)
• ACT measured every 30min
• Usually 1/3rd of initial heparin dose given every hour to
maintain target ACT
Reversal
• Protamine (1mg/100U of heparin) given
• Heparin-protamine complex  activates
complement  hypotension
– May need to add Calcium (2mg/1mg
protamine)
• After 1/3rd of protamine dose administered,
blood must not be returned to the
cardiotomy reservoir from the surgical field
• Neutralization of heparin must be
confirmed by an ACT
Going on Bypass
• Started on surgeon’s request with concurrence of the
anaesthesiologist and perfusionist
• As VR enters machine, perfusionists progressively
increases arterial flow while watching BP and all reservoir
volumes
• 6 observations are critical:
–
–
–
–
–
–
Is venous drainage adequate for desired flow?
Is pressure in arterial line acceptable?
Is arterial blood adequately oxygenated?
Is systemic arterial pressure acceptable?
Is systemic venous pressure acceptable?
Is the heart adequately decompressed?
• Once on full bypass for at least 2 min, lung ventilation
discontinued, perfusion cooling may begin, aorta may be
clamped for cardiac arrest
Key determinants of Safe Perfusion
• Blood flow rate
– Basic CO determined by O2 consumption
(250ml/min)
– Generally accepted flow rate with HCT 25%,
deeply anaesthetized, muscle-relaxed
patient = 2.4L/min/m.sq
– For every ↓ 10ºC = ↓ 0.5 of O2 consumption
– Also ↓flow = ↓O2 consumption
Oxygen Consumption Nomogram
Kirklin and Barrett-Boyes suggest that flows be reduced only to levels that
permit at least 85% of maximal O2 consumption.
Key determinants of Safe Perfusion
• Arterial Pressure
– Systemic BP = flow rate x viscosity (HCT) x vascular
tone
– At 24% HCT, MAP between 55-60, adequate to
maintain autoregulation
• In older patients with vascular disease, MAP
generally maintained between 70-80
– Higher MAPs undesirable as it increases blood in the
operative field d/t to collateral blood flow to heart
and lungs
– Hypotension – causes are low pump flow, aortic
dissection, vasodilation
• Phenylephrine, vasopressin
– Hypertension – nitroprusside (arterial dilator),
nitroglycerine (venodilator and pulmonary vessel)
Key determinants of Safe Perfusion
• Hematocrit
– Ideal level still under debate
– Low HCT = reduced viscosity, hemolysis,
and O2 carrying capacity and autologous
blood transfusion
– Viscosity remains stable when % HCT and
Temp are equal
– General acceptable %HCT is 20-25%
Key determinants of Safe Perfusion
• Temperature
– Another unsettled parameter
– Hypothermic temp (25-30ºC)
• Adv=protects brain, permit perfusion at low
flows and HCTs, support hypothermic
quadriplegia
• Disadv=enzyme and organ dysfuntion,
aggravates bleeding, increases SVR, delays
cardiac recovery, higher embolic risk
– Since embolic risk of cerebral injury >
perfusion risk, tepid temperature (33-35ºC)
recommended
Key determinants of Safe Perfusion
• pH/Pco2
• 2 strategies
– pH-stat – maintains pH at 7.40 at all temperatures
• Requires addition of CO2 while cooling
• Cerebral blood flow is higher, and uncoupled to
cerebral oxygen demand
• Recommended for pediatric surgery
– Alpha-stat – pH allowed to increase during cooling
• Blood becomes alkalotic
• Cerebral blood flow is lower, autoregulated, and
coupled to cerebral oxygen demand
Key determinants of Safe Perfusion
• PaO2
– >150mmHg to assure complete arterial
saturation
• Glucose
– Some concerns that hyperglycemia related
to neurologic injury
• Still under research
Patient Monitors
•
•
•
•
Radial/brachial/femoral arterial catheter
CVP via jugular venous catheter
Routine use of Swan-Ganz PA cath controversial
TEE – important tool for cathether and vent
insertion, aortic atherosclerosis, thrombi and air
assessment, contractility, valve function, diagnosis
of dissection
• Urine output
• Temperature – Nasopharyngeal or tympanic
membrane temp used more commonly
– arterial line temp correlates best with jugular venous
bulb temp (best surrogate for brain temp)
Coming off Bypass
• Prior to stopping
– Patient re-warmed to 34-36ºC
– heart defibrillated, lungs re-expanded and
ventillated
– Cardiac rhythm, HCT, blood gases, acidbase status, plasma electrolytes reviewed
– TEE for air detection
– Caval catheters are adjusted to ensure no
obstruction to venous return to heart
Coming Off Bypass
• Weaning off bypass
– Venous line gradually occluded
– As flow rate approaches zero, volume is
added/removed to keep arterial and venous
pressures within physiologic range
– Cardiac filling, contractility, and repairs are
assessed while weaning
– Once sats near 100%, ETCO2 >25mmHg,
and MvO2 >65% = satisfactory circulation
– If all satisfied, can give protamine, remove
annulations.
Objectives
1
History of CPB
2
Principle of CPB
3
Components and Technique of CPB
4
Complications
Complications
Coagulation
Inflammatory
Systemic Dysfunction
Pathophysiological Response
• Triggers
– Passage of blood through non-endothelial
circuitry
– Temperature change, acid-base balance,
hemodilution, non-pulsatile flow, drugs,
circulatory pump and bypass mechanics
Activation of Blood Constituents
• Plasma protein systems (5)
–
–
–
–
–
Contact
Intrinsic System
Extrinsic System
Complement Cascade
Fibrinolytic Cascade
• Cellular systems (5)
–
–
–
–
–
Platelets
Neutrophils
Monocytes
Lymphocytes
Endothelial cells
Plasma Proteins
• Blood + non-endothelialized surface 
adsorption of plasma proteins onto the
surface
• Protein layer created
• LAYER VARIES WITH THE MATERIAL
AND DURATION OF EXPOSURE
• Dynamic between circulating and adsorbed
proteins is established
• Heparin coated circuits change the
reactivity of these proteins but DOES NOT
reduce thrombogenecity
Plasma Protein System
•
Contact System – procoagulant + pro-inflammatory
•
Intrinsic System  procoagulant
•
Extrinsic System  procoagulant
•
Complement System  pro-inflammatory
•
Thrombin production – pro-coagulant + anti-coagulant
– Activated by non-endothelial surfaces
– F12, 11, prekalikrein and kinogen
– Activates the intrinsic pathway, complement pathway, and neutrophils
– Activated by the contact system
– Activates F10 (300,000x more than Extrinsic system)
– Wound surface tissue damage  Tissue Factor  Extrinsic system
activation
– F12  C1 of the classic complement pathway
– CPB  alternative complement pathway (C3 based)
– Classic + Alternative pathways increase capillary permeability, alter
vasomotor tone, impair cardiac function, mast cell and platelet
activation
– Stimulates endothelial cells to produce TPA  progressive fibrinolysis
Cellular System
•
Platelet activation
•
Neutrophils
•
Monocytes
•
Lymphocytes (B-cells, natural killer cells, T-cells)
•
Endothelial cells
– Activated by G2b/3a receptor complex
• Stimulants include heparin, thrombin, complement, plasmin, PAF,
adrenaline
• Result in decrease platelets  major cause of post-op bleeding
– Activated by complement, kallikrein, F12, interlukins
• Increase neutrophils in lungs increase capillary permeability 
interstitial edema
– Activated by contact with circuit, complement, and endotoxins
• Help to produce TF and multiple cytokines
– Reduced by CPB
– Increase risk of infection post-op
– Increase in TPA production in response to thrombin  activates
fibrinolytic pathway
Optimal Balance
Systemic Dysfunction
• Major causes = micro-emboli + hypoperfusion
• Hemostatic
– Complications related to Platelet activation, heparin,
protamine
– Bleeding time after full CPB reversal does not return to
normal for 4-12 after bypass
• Fluid balance
– Massive shift into interstitum
• Increase in inflammatory process  increase in capillary
permeability, increase in systemic venous pressure,
volume loading
• Endocrine
– Stressors, hypothermia, CPB, non-pulasite flow 
increased cortisol, adrenaline and noradrenaline, glucose
for at least 24hrs after surgery
– Decrease in circulating T3
Systemic Dysfunction
• Cardiac
– Difficult to decipher post-op cardiac dysfunction and
injury due to CPB
– Subject to emboli, cytotoxins
– Myocardial “stunning”, reperfusion injury
•
Lung
– Pulmonary edema (complement activation and
neutrophil sequestration)
– CPB reduces effect of natural surfactant  reduces
pulmonary function
– CPB increases shunts, reduces compliance and
functional residual volume
– ARDS
Systemic Dysfunction
• Kidney
– Hemodilution, microemboli,
catecholamines, diuretics, hypothermia,
aprotinin  all impair renal function
• GI
– Peptic ulcers (from surgical stress)
– Pancreatitis and mild jaundice
– Gastroenteritis (from increase inflammatory
response)
Systemic Dysfunction
• Brain
– Most sensitive organ exposed to injury by CPB
– Difficult assessment – but hard outcomes are stroke,
delirium, coma
– Risk increases with age (>60)
• Proximal aortic atherosclerosis and PHx of
neurologic disease ↑ ↑ ↑ ↑ risk
– Mechanism – microemboli (air, debris, fat) or
hypoperfusion
– Protection strategies
• Mild hypothermia, HCT>25%, cerebral perfusion, offpump
Neuro-dysfunction follow CVSx
Percentages of patients with deficits on two or more tests. (n = 374).
Objectives
1
History of CPB
2
Principle of CPB
3
Components and Technique of CPB
4
Complications
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Introduction
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Strategy
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Challenges Forward
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History
Arterial
Cannulation
Aortic
Axillary
Femoral
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Duis autem vel eum iriure
dolor in hendrerit in vulputate
velit esse molestie
consequat, vel illum dolore
eu feugiat nulla facilisis .
Concept
Duis autem vel eum iriure
dolor in hendrerit in vulputate
velit esse molestie
consequat, vel illum dolore
eu feugiat nulla facilisis .
Concept
Duis autem vel eum iriure
dolor in hendrerit in vulputate
velit esse molestie
consequat, vel illum dolore
eu feugiat nulla facilisis .
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Concept
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Add title text
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