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DR G SIYAKA

Obstetric anaesthesia

2013-06-03

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OUTLINE

Physiological changes of pregnancyAnaesthesia for caesarean deliveryAnalgesia for labourComplications and contraindications to

neuraxial anaesthesiaMedical conditions in pregnancyObstetric emergencies

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Physiological changes of pregnancy

CardiovascularChanges in CO, SV,HRChanges in BP,SVRAorta-caval compression

RespiratoryLung mechanicsGas exchangeOxygen consumption

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Physiological changes of pregnancy

Airway

HaematologicalBlood volumeAnaemia, thrombocytopaeniaClotting factors

GastrointestinalDelayed stomach emptyingLOS tone

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Evaluating the pregnant patient

History

Examination

Special investigations

Informed consent and premed

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Anaesthesia for caesarean delivery

Anaesthetic techniquePre-operative evaluationTheatre preparation

Regional anaesthesia(spinal)

Fluid co-loadBaseline monitoringAseptic technique

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Anaesthesia for caesarean delivery

NeedleDrugsTesting your blockManaging hypotensionUterotonic therapy

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Anaesthesia for caesarean delivery

General anaesthesia

Only if contra-indication to spinal anaesthesia

Pre-op evaluation ,check aspiration prophylaxis been given

MonitoringPre-oxygenation, RSI with cricoid pressureConfirm intubation and allow surgeon to start

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Maintenance of anaesthesia with volatile MAC 0.75,oxygen 50% and nitrous oxide/air

OxytocinAnalgesia – opioids, NSAID, paracetamol,+/_

block(TAP)Reverse NMBsExtubate awake

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Analgesia for labour

Physiology of labour

1st stage

2nd stage

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Analgesia for labour

Pre-operative evaluationCheck emergency equipment

Epidural analgesiaPreparationNeedleDrugs including test doseInfusion regimens

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Analgesia for labour

Combined spinal epidural(CSE)

Rationale for doing CSENeedlesDrugsInfusion regimens

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Complications of neuraxial anaesthesia

HypotensionHigh spinal blockadePDPH ( classic description)Infection ( meningitis, arachnoiditis, epidural

abscess)Spinal haematomaFailed spinal

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Contraindications to neuraxial blockade

AbsolutePt refusal, uncooperativeSevere hypovolaemiaInfection at injection siteCoagulopathy ( platelets, INR, urea)Fixed output states (AS, constrictive

pericarditis ,HOCM)Raised intracranial pressurePatient refusal

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Contraindications to neuraxial blockade

Relative

Systemic sepsisActive neurological diseasePrevious back surgeryComplex surgery

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Medical conditions in pregnancy

HypertensionClassification-chronic hypertension -pre-eclampsia -eclampsia -gestational hypertensionProblems related to pre eclampsia

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Medical conditions in pregnancy

Pre eclampsiaTreatment goals

Seizure prophylaxisBlood pressure control : methyldopa, CCB,

labetalolFluid managementULTIMATELY DELIVERY OF PLACENTA

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Obstetric emergencies

Major obstetric haemorrhagei.e. blood loss> 500ml post vaginal delivery,

1000ml post c/section delivery

Causes APH (placenta praevia, placental

abruption, uterine rupture) PPH( atony, retained tissue, trauma,

coagulopathy)

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Management

AssessHistory medical and obstetricExam ,may even need an EUAMonitor ECG ,NIBP ,oxygen saturationConsider invasive monitoring IABP , CVP

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Resuscitate

Oxygen 10- 15 L/minIf pre-delivery keep in L lateralTwo large bore cannulaeTake blood for FBC , clotting profile, X matchFluids : crystalloid , colloid ,bloodTransfuse if Hb < 8 g/dl, platelets < 75 and

still bleeding, PTT > 1.5 , fibrinogen < 1.0 g/L

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Stop the bleeding

Bimanual compressionOxytocin CarboprostMisoprostol

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Stop the bleeding

Uterine balloon tamponadeB Lynch compression suturesDevascularisation Hysterectomy as last resort

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Adjuncts

Cell salvageInterventional radiologyMethotrexateTranexamic acidRecombinant factor VIIa

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Obstetric emergencies

Amniotic fluid embolism

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