Table 3.
Diagnosis of and investigations in amniotic fluid embolism.
| Diagnostic criteria |
|---|
| Recommended in the USA and the UK [[38], [39], ∗[40]] |
| 1. Acute hypotension or cardiac arrest |
| 2. Acute hypoxia |
| 3. Coagulopathy or severe clinical haemorrhage in the absence of other explanations |
| 4. All of these occurr during labour, caesarean delivery, or dilation and evacuation, or within 30 min postpartum with no explanation for the findings |
| UKOSS and Australian criteria [32] |
| Acute maternal collapse with acute foetal compromise, cardiac arrest/rhythm problems, coagulopathy, hypotension, haemorrhage, premonitory symptoms, seizures, shortness of breath (excluding haemorrhage as presenting features without evidence of coagulopathy or cardiorespiratory compromise); or Finding of foetal squames or hair in the lungs at autopsy |
| Diagnostic criteria in Japan [31] |
| Symptoms during pregnancy or within 12 h of delivery, medical treatment required for cardiac arrest, bleeding ≥1500 mL of unknown origin within 2 h of delivery, DIC, respiratory failure, and symptoms not explained by other diseases |
| Investigations [24,31,32,34] |
| Echocardiogaphy (transthoracic or transoesophageal) - assess right and left ventricular function and cardiac disorders to guide fluid resuscitation |
| Electrocardiography - display tachycardia, right ventricular strain pattern, and ST and T wave abnormalities, arrhythmia, asystole, pulseless electrical activity, and myocardial infarction |
| Chest X-ray - detect pulmonary oedema and exclude other disorders |
| Maternal blood tests - complete blood count and coagulation profile, renal and liver function, blood electrolytes, arterial pH and blood gas, glucose, and cardiac enzymes |
| Zinc-coproporphyrin-1 (Zn-CP1) (<1.6 pmol/L) - from meconium, detection suggests amniotic fluid embolism, need to shield blood sample from light to prevent degeneration |
| Sialyl-Tn (STN) (<46 IU/mL) - from mucin in meconium, detection suggest the diagnosis |
| Complement 3 (80–140 mg/dL) and 4 (11–34 mg/dL) - decreased levels from inflammation or allergy and in amniotic fluid embolism |
| Interleikin-8 (<20 pg/mL) - level increased by DIC, SIRS, or ARDS |
| C1 esterase inhibitor (C1INH) - inhibitor of C1 esterase, Factor XIIa and kallikrein, and is decreased in AFE |
Abbreviations: UKOSS = United Kingdom Obstetric Surveillance System, DIC = disseminated intravascular coagulation, SIRS = systemic inflammatory response syndrome, ARDS = acute respiratory distress syndrome.