Tiziana Frusca Università di Parma Direttore UO Ostetricia e

Tiziana Frusca
Università di Parma
Direttore UO Ostetricia e Ginecologia
Azienda Ospedaliera Universitaria di Parma
[email protected]
BASELINE RATE
- Bradycardia not accompanied by absent
baseline variability
- Tachycardia
BASELINE FHR VARIABILITY
- Minimal baseline variability
- Absent baseline variability with no
recurrent decelerations
-Marked baseline variability
ACCELERATIONS
- Absence of included accelerations after
fetal stimulation
PERIODIC OR EPISODIC DECELERATIONS
- Recurrent variable decelerations
accompanied by minimal or moderate
baseline variability
-Prolonged deceleration more than
2minutes but less than 10 minutes
-Recurrent late decelerations with
moderate baseline variability
-Variable decelerations with other
characteristics such as slow return to2
baseline, overshoots or shoulders
3
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Classificazione ACOG e severità della acidemia
5
BJOG 2014;121:1063–1070.
tracking the evolution of fetal
defensive and compensatory responses to hypoxic
ischaemic insults, then it should be possible, at least
theoretically,to discriminate from a pool of ‘pathological’
CTGs those etuses at genuine risk of acidosis and
acidaemia (increased H+ in the bloodstream) or impaired
neonatal adaptation from the subset that are no
guidelines are silent on scenarios associated with fetal
damage, such as fever, chorioamnionitis, fetal systemic
inflammatory response syndrome (FSIRS) and its noxious
synergistic interaction with hypoxia, fetal strokes, lack of
fetal cycling behaviour, maternal disease, and the recognition
of maternal heart rate (MHR) monitoring, to name a
few.
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• Intrapartum FHR interpretation—a step-wise physiologic
approach
•
Step 1—the normal and the abnormal initial CTG
•
Step 2—recognition of the compensated and the decompensating fetus
– Slowly evolving hypoxia
– Subacute hypoxia
– Acute hypoxia (prolonged FHR deceleration and bradycardia)
The continuing focus on the morphological appearances of
FHR decelerations by current guidelines and training modules
denies the clinician an understanding of how the fetus
defends itself, compensates for intrapartum hypoxic ischaemic
insults, and the ability to recognise the patterns that suggest
loss of compensation.
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from “pattern recognition“
to a “physiological interpretation”
• labor as a stress test
• oxytocin and prostaglandin : useful but potentially dangerous
• the most important question: “is the fetus able to cope?
• baroreceptor response and chemoreceptor response
• understanding what is happening and being able to predict
next fetal adaptation
• the response is almost always not “to rush for a cesarean
section”
• intrauterine resuscitation
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REGOLAZIONE DEI BAROCETTORI
STIRAMENTO
AUMENTO DELLA
PRESSIONE
ARTERIOSA
ENDOLUMINALE
 RIDUZIONE DELLA
FREQUENZA CARDIACA
 VASODILATAZIONE
PERIFERICA
REGOLAZIONE DEI CHEMOCETTORI
GLOMI AORTICI E
GLOMI
CAROTIDEI
CHEMOCETTORI
RISPOSTA CRONICA (IPOSSIA CRONICA):
↓ FREQUENZA CARDIACA
↓O2
↑CO2
↓pH
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Monitoring..means to monitor fetal
hearth
AND CONTRACTIONS
WHY TO MONITOR
WHY TO MONITOR
Uterine contractions
and placental flow
• The
oxigen
and
CO2
exchange from fetus to mother is
interrupted during a contractions
(when the uterine pressure is 30
mmHg or more), because an
interruption of the ematic
placental flow occurs
• After a contraction, the fetus
needs 60 – 90 seconds to get
again to a normal oxygenation
• The fetal ability to manage the
labour overall depends on his
ability to rapidly get a normal
oxygenation
after
the
contractions
Uterine contractions
and placental flow
- Oxygen extraction from other
tissues increased
- Reduction of non-essential
activities
Mechanism of fetal defence
- Sympathetic activities increased
- Ematic flow redistribution
- Anaerobic metabolism
Intact
Reduced
- The fetus is able to react to
- Decrease in reserves for a fetus
the acute hypoxia of the labour who was healthy but was exposed
to a lot of hypoxial stimuli. Postterm fetus
Absent
- Antenatal problems with
chronic distress. Mechanisms of
defence already used. IUGR
fetus.
- Optimal reaction to hypoxia
- Total compensation
- Reduced reaction to hypoxia
- Reduced compensation
- Minimal or absent reaction to
hypoxia
- Decompensation
- Fetal distress markers
- Low risk of asphyxial damage
- Variable markers of fetal distress - Typical signs of fetal distress
- Present risk of asphyxial damage missed
High risk of asphyxial damage
• pro e contro CTG in travaglio di parto
• indicazioni nel basso rischio (cosa é il basso rischio?)
• come eseguire la cardiotocografia
• analisi del tracciato
– dalla valutazione “gestaltica” (pattern recognition) alla interpretazione fisiopatologica
• classificazione del tracciato
•
compiti e responsabilità della ostetrica/ compiti e
responsabilità del medico
• decisioni cliniche
• il periodo espulsivo
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Admission test
• tracing acquisition:
– maternal position
– paper scales and speed
– external vs internal monitoring
– simultaneous maternal hearth rate
– monitoring twins
– storage of tracing
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speed velocity
The horizontal scale for CTG registration and viewing is commonly called “paper speed” and available
options are usually 1, 2, or 3 cm/min.
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monitoring twins
•
Continuous external FHR monitoring of twin gestations during
labor should preferably be performed with dual channel monitors that
allow simultaneous monitoring of both FHRs, as duplicate monitoring
of the same twin may occur and this can be picked up by observing
almost identical tracings.
. During the second stage of labor, external FHR monitoring of twins is particularly
affected by signal loss, and for this reason some experts believe that the presenting
twin should preferably be monitored internally for better signal
quality. Other experts believe that external monitoring of both
twins is acceptable, provided that distinct and good quality FHR signals
can be obtained.
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external versus internal
external monitoring
External FHRmonitoring is more
prone to signal loss, to
inadvertent monitoring of the
maternal heart rate (Fig. 1) and
to signal artifacts such as
double-counting (Fig. 2) and
half-counting ,
particularly during the second
stage of labor.
storage of tracing
patient name, place of recording, “paper
speed,” and date and time when acquisition
started and ended. digital CTG archives
Noi aggiungiamo nel timbro CTG:
nome dell’ostetrica PA e FC della donna,
nome del medico che valuta il tracciato
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analysis of tracing
• baseline
– normal baseline 110-160
– tachycardia > 160 10 minutes
• epidural analgesia, maternal pyrexia, betaagonist, parasympathetica
blockers, initial phase
of non acute fetal hypoxemia
– bradycardia < 110 >10 min
• maternal hypothermia, betablockers,fetal arythmia, postdate
pregnancies
• Variability
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analysis of tracing
• accelerations increase of more 15 bpm more than 15 sec
– after 32-34 w establishment of fetal behavioural states : absence of
accelerations during deep sleep for 50 minutes (cycling!!!)
– accelerations coincident with contractions especially in the second stage of
labor suggest possible erroneous recording of the maternal hearth rate
analysis of tracing
• The expulsive effort of women during the second stage of
labour is associated with a maternal tachycardia and hence
‘accelerations’ of the fetal heart rate observed with
contractions or maternal pushing during second stage must be
viewed with caution
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analysis of tracing
• decelerations
– early
– variable : baroreceptor mediated responce to increased arterial pressure seldom
correlated to acidosis
–
but if Ushaped component, reduced variability, duration >3 min
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analysis of tracing
• late decelerations
– chemoreceptor mediated response to fetal
hypoxemia when contraction are adequately
monitored dec start more than 20 sec after the
onset of contraction
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Acute hypoxia
• prolonged decelerations lasting more than 3 min
chemoreceptor mediated component indicating
acute hypoxia and acidosis and require emergent
intervention -association with hypoxia /acidosis
• pH drops 0.01 every 1 min
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CTG classification
• ctg classification every 30 minutes
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actions in situations of suspected
fetal hypoxia/acidosis
• excessive uterine activity
– stop oxytocine
– tocolysis
– stop pushing
• aortocaval compression
– change maternal position
– fluid administration
during the second stage of labor acidosis may develo more rapidly
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Second stage- periodo espulsivo
Il fatto di percepire l’espletamento del parto come temporalmente vicino, determina nel II stadio una maggior tendenza
all’accelerazione sistematica dei tempi di fronte a tracciati CTG non rassicuranti o “indeterminati”. Questo si traduce in una
sottovalutazione degli effetti deleteri della tachisistole, che non solo non viene “corretta” se presente, ma talvolta
deliberatamente provocata mediante un utilizzo spesso indiscriminato dell’infusione di ossitocina, con un controllo meno
rigoroso dei dosaggi rispetto al periodo dilatante. L’incitamento ad esercitare sforzi espulsivi vigorosi, su comando, a glottide
chiusa e di durata prefissata, con l’intento di accelerare l’espletamento del parto si inserisce negativamente in questo contesto.
(LG SLOG) Antonella Cromi
•
nessuna delle principali classificazioni della cardiotocografia proposte da società scientifiche internazionali distingue
il periodo dilatante dall’espulsivo
•
la classificazione proposta da Melchior & Bernard nel 1972, rivista da Piquard nel 1988 dimostrato un valore
prognostico
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Misure correttive in presenza di
CTG anomala in periodo espulsivo
Cosa viene fatto:
Si mette la donna in
posizione litotomica
Si aumentano le contrazioni
Si incoraggia la donna a
spingere ad ogni
contrazione,
Si comincia a fare
l’”appoggino”…
Spesso si crea panico
Cosa bisognerebbe fare:
Rallentare le contrazioni
(ridurre la ossitocina!)
Far spingere la donna a
spinte alternate
Far spingere in posizione
laterale
Stimolare lo scalpo fetale
O2?? Liquidi??
“Calma e sangue freddo”
Take home messages
• La “demonizzazione” della
cardiotocografia ha origini nel suo
scorretto utilizzo, scorretta
interpretazione e scorretta risposta
• L’outcome su cui valutare la
sensibilità della cardiotococografia in
travaglio non può essere la mortalità
o la paralisi cerebrale
• L’ analisi dei tracciati secondo la
pattern recognition determina errori
nella valutazione prognostica
• La classificazione del tracciato deve
esser ripetuta periodicamente
analizzando tutte le sue componenti e
confrontando con il primo tracciato
• Il tracciato va contestualizzato nella
situazione clinica della madre e del
feto
• Un tracciato classe 2 ACOG o sopetto
FIGO non significa necessariamente un
taglio cesareo o un parto operativo
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St.George’s management
Testo
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