Obstetric emergencies

Question 1

AFE: pathophysiology

Answer 1

1. Amniotic fluid (fetal cells/other antigenic material) into maternal systemic circulation via breach in maternal-fetal interface
2. Abnormal activation of humoral and immunological processes and release of vasoactive and procoagulant substances

Vasoactive substances
3. ↑ pulmonary pressure, ↑ RV pressure, RV begins to fail -> LV failure and systemic hypotension, from RV or direct effect of hypoxic injury, release of inflammatory mediators
4. Acute pulmonary HTN -> severe V/Q mismatch, cardiogenic pulmonary oedema, hypoxaemic respiratory failure

Procoagulant substances
5. Activation of factor VII and Plts + release of inflammatory mediators -> activates coagulation cascade -> DIC -> ischaemic distal organ dysfunction and multi-organ failure -> haemorrhage further contributes to haemodynamic instability