Amniotic fluid embolism: literature review and an integrated concept of pathomechanism

Literature concerning procoagulant activity of the amniotic fluid and pathomechanism of amniotic fluid embolism (AFE) was surveyed and a new concept of its pathogenesis, called the integrated concept of AFE, was presented. According to this concept, two components of the amniotic fluid are involved: 1) apoptosis-affected amniotic cells showing a special role in the initiation of disseminated intravascular coagulation (DIC) and 2) leukotrienes (formerly called slowreacting substances), inducing bronchial and pulmonary vascular smooth muscle contraction. Although each of these components initiates a different pathogenic pathway, they both lead to the formation of a mechanical barrier on blood flow through the lungs (amniotic debris + microemboli) and/or functional barrier (pulmonary vasoconstriction). An old dilemma, concerning indications for heparin therapy in AFE was recalled in the light of the new concept.