Amniotic Fluid Embolism

Abstract

Amniotic fluid embolism is an obstetric emergency in which amniotic fluid, fetal cells, hair, or other debris enters mother’s bloodstream through placental bed and thereby initiates allergic reaction resulting in cardiopulmonary collapse, respiratory compromise, and coagulopathy leading to massive hemorrhage. AFE is classically characterized by a triad of hypoxia, hypotension, and consumptive coagulopathy. It specifically occurs during labor and delivery or immediate postpartum usually either within 5 min or 48 h postpartum or during blunt abdominal trauma or procedures like cervical suture removal and transabdominal amniocentesis during pregnancy. Various risk factors include: 1. Maternal age >35 years 2. Placenta previa or abruption 3. Cesarean or assisted delivery procedures (forceps, vacuum) 4. Eclampsia 5. Fetal distress 6. Meconium-stained amniotic fluid The pathogenesis of AFE is complicated and not clear; its development envisages mechanical obstruction of the pulmonary vessels by amniotic fluid components to humoral and immunological factors. Entrance of amniotic fluid to maternal circulation: Endocervical veins Placental insertion site Site of uterine trauma Patient presents clinically in the following phases: First phase: In the first phase, the patient experiences acute shortness of breath due to pulmonary hypertension. This rapidly progresses to cardiac failure because of pressure overload leading to a reduction of perfusion to the heart, lungs, and finally brain. Not long after this stage, the patient will lose consciousness due to circulatory collapse leading to death of mother unless managed on war footing. Second phase: About 40% of the initial survivors will pass onto the hemorrhagic phase after left heart failure. The blood loses its ability to clot and there is excessive bleeding. Collapse of the cardiovascular system leads to fetal distress and death unless the child is delivered swiftly. The treatment is essentially supportive. Early and aggressive resuscitation is essential for maternal and neonatal survival.