Amniotic Fluid Embolism Max Brinsmead MB BS PhD May 2015

Amniotic Fluid Embolism A rare event – 3.3 per 100,000 deliveries in an Australian study based on ICD10 Was once associated with an 85% maternal mortality - 50% within the first hour 35% maternal mortality with modern intensive care and 32% perinatal mortality if it occurs before delivery

AFE – Risk Factors Multiparity Abruption Intrauterine Fetal Death Tumultuous labour Oxytocin or Prostaglandin hyperstimulation Caesarean section Manual removal of the placenta

AFE - Pathophysiology Probably an anaphylactoid-type reaction to the intravascular ingress of amniotic fluid This causes widespread vasoconstriction including pulmonary and cardiac vessels There is ↓myocardial contractility and acute left heart failure If the mother survives the initial cardiorespiratory failure then DIC and haemorrhage is inevitable Survivors may suffer stroke due to cerebral infarction The presence of fetal amniotic squames in the maternal lung at autopsy is said to be “diagnostic”

AFE – Clinical Presentations Acute fetal distress followed quickly by maternal collapse with hypotension, dyspnoea and cyanosis Sudden loss of consciousness or seizure Often proceeds or occurs immediately after delivery Maternal collapse during Caesarean section Followed by profuse post partum haemorrhage

AFE – Diagnosis The diagnosis is a clinical one Exclude alternatives (if possible) Placental abruption Uterine rupture Eclampsia Thromboembolism Cardiogenic causes of acute CCF Drug toxicity e.g. Local anaesthetics Anaphylaxis Transfusion reaction Massive aspiration of gastric contents Useful Tests Blood gases ECG Blood Coagulation tests Lung CT to look for signs of thromboembolism Serum zinc coproporphyrin >35 nmol/L

AFE - Management Remember A, B, C Endotracheal intubation and IPPV with 100% O2 ASAP Aggressive fluid replacement preferably with CVP monitoring Aggressive use of oxytocic agents plus whatever to control PPH Pressor agents eg Dopamine usually required Multidisciplinary Intensive Care (including a haematologist) FFP and Platelets for DIC ?Heparin ?Factor VIIa