Amniotic Fluid Embolus

• AFE is rare but one of the leading causes of sudden maternal collapse in labour or immediately postpartum.
• Clinical diagnosis – there is no rapid test. Exclude more common causes (haemorrhage, PE, anaphylaxis, eclampsia, sepsis).
• Management is supportive: high-quality resuscitation, ventilation, vasopressors, and aggressive correction of DIC.
• Requires immediate multidisciplinary response (ED, obstetrics, anaesthetics, ICU, blood bank).

1. Call for help early – activate obstetric emergency / code blue. Ensure airway, breathing, circulation.
2. If no pulse → start CPR with manual uterine displacement. Attach monitors (ECG, SpO₂, NIBP).
3. Provide high-flow oxygen; secure airway early (rapid sequence intubation) if not in arrest.
4. Large-bore IV/IO access; start fluid resuscitation and vasopressors for hypotension as per shock protocols.
5. Simultaneously consider differential: haemorrhage, eclampsia, PE, anaphylaxis, sepsis, cardiomyopathy.
6. If cardiac arrest and pregnancy ≥ 20–24 weeks → perimortem caesarean section within 4–5 minutes of arrest.
7. Send urgent bloods: FBC, coag profile, fibrinogen, ABG, lactate, cross-match, LFT/U&E.
8. Recognise AFE pattern: sudden hypoxia + hypotension/collapse + bleeding/DIC in temporal relationship to labour/delivery/uterine procedure.
9. Commence massive transfusion protocol if ongoing bleeding and coagulopathy.

Classic description: two-phase presentation – first cardiopulmonary collapse, then haemorrhagic phase with DIC.

• Phase 1 – Cardiopulmonary:
  • Sudden onset dyspnoea, chest tightness, sense of impending doom.
  • Rapid hypoxia: cyanosis, low SpO₂ despite oxygen.
  • Tachycardia, hypotension, arrhythmias, pulmonary oedema.
  • Seizures or altered consciousness; up to 20% present primarily with a seizure.
  • Cardiac arrest can be the first sign.
• Phase 2 – Haemorrhagic / DIC:
  • Massive uterine bleeding and/or bleeding from IV sites, wounds, mucosa.
  • Laboratory evidence of consumptive coagulopathy (prolonged PT/aPTT, low fibrinogen, thrombocytopenia).
  • Uterine atony and postpartum haemorrhage.

AFE is a diagnosis of exclusion – rule out:

• Massive obstetric haemorrhage (e.g. uterine atony, placenta accreta, uterine rupture).
• Pulmonary embolism (thromboembolic).
• High spinal / epidural block, local anaesthetic toxicity.
• Drug-induced anaphylaxis (e.g. antibiotics, oxytocin, anaesthetic agents).
• Septic shock (chorioamnionitis, puerperal sepsis).
• Eclampsia / severe pre-eclampsia (hypertension, proteinuria, seizures).
• Peripartum cardiomyopathy, myocardial infarction, air embolism.

Do not delay resuscitation for investigations. Send targeted tests once ABC is underway.

• ABG: severe hypoxia, respiratory/metabolic acidosis, raised lactate.
• FBC: anaemia from bleeding, thrombocytopenia.
• Coagulation profile & fibrinogen: prolonged PT/INR, aPTT, low fibrinogen consistent with DIC.
• Cross-match and prepare blood products (RBCs, FFP, cryoprecipitate, platelets).
• U&E, LFTs: assess organ dysfunction.
• ECG & CXR: evaluate for pulmonary oedema, other cardiac causes.
• Point-of-care echo (if available) may show acute right ventricular strain or global dysfunction.

Definitive diagnosis is often made post-mortem (fetal squames/debris in pulmonary circulation). In practice, we treat presumptively based on the clinical syndrome.

Airway & Breathing

• High-flow oxygen via non-rebreather mask initially.
• Early intubation and mechanical ventilation for severe hypoxia, respiratory distress or decreased level of consciousness.
• Consider PEEP for pulmonary oedema; titrate to SpO₂ and haemodynamics.

Circulation

• Rapid IV fluid resuscitation, balanced crystalloids initially.
• Vasopressors (e.g. noradrenaline) for persistent hypotension after fluids.
• Inotropes may be required for myocardial dysfunction (guided by echo/ICU team).
• Continuous monitoring: invasive arterial line and central access if feasible and not delaying resus.

Haemorrhage & Coagulopathy

• Activate massive transfusion protocol early if bleeding and coagulopathy are evident.
• Administer:
  • Packed red cells to maintain adequate Hb and oxygen carrying capacity.
  • Fresh frozen plasma for clotting factors.
  • Cryoprecipitate or fibrinogen concentrate to correct low fibrinogen.
  • Platelets if thrombocytopenic or heavy bleeding.
• Coordinate closely with laboratory/blood bank; repeat coagulation studies and fibrinogen levels.

Obstetric Management

• Continuous involvement of obstetric and anaesthetic teams.
• Uterine atony and postpartum haemorrhage require:
  • Uterine massage, uterotonics (e.g. oxytocin, misoprostol; avoid ergometrine if severe hypertension).
  • Mechanical methods (balloon tamponade), surgical haemostasis if required.
• Perimortem C-section if cardiac arrest and pregnancy ≥ 20–24 weeks – improves both maternal and neonatal outcomes.

Post-resuscitation Care

• All survivors require ICU admission for ongoing respiratory, cardiovascular and coagulation support.
• Monitor urine output (indwelling catheter) and organ function carefully.

• Any suspected or confirmed AFE → ICU level care if the patient survives initial resuscitation.
• Ensure thorough documentation of:
  • Timeline of events (onset of symptoms, delivery time, arrest and resuscitation details).
  • Vitals, interventions, drugs and blood products given.
  • Discussions with obstetric, anaesthetic, ICU and blood bank teams.