The complement system may play a role in this mechanism of the AFE syndrome. Consequently, clinical manifestations of AFE including coagulopathy, increased vascular permeability, vasoconstriction of pulmonary, systemic and coronary vessels, and bronchospasm could all be seen to proceed by a humoral mechanism.Ī possible immunologic mechanism has been proposed as a third contributing factor, based on the many similarities that exist between clinical and hemodynamic findings of AFE and anaphylactic shock. Amniotic fluid has both vasoactive and procoagulant characteristics that have been proposed to be mediated by prostaglandins, endothelin, platelet activating factor, leukotrienes, bradykinin and tissue factor. proposed changing the name of the syndrome from “amniotic fluid embolus” to “anaphylactoid syndrome of pregnancy”. Clinical manifestations of AFE may be similar to that of anaphylactic or septic shock. There is evidence that once AFE has occurred certain biochemical mediators associated with it can trigger systemic inflammatory responses. Amniotic fluid, once forced into the maternal systemic circulation, may lead to circulatory obstruction, including that of the pulmonary circulation. Commonly suspected sites of amniotic fluid entry into the maternal circulation are small tears in the endocervix and lower uterine segment – both frequently seen during labor and delivery. Autopsy reports from fatal cases of AFE report epithelial squamous cells, lanugo hair, and fat from vernix or infantile mucin in the maternal pulmonary vasculature. The clinical syndrome itself is precipitated when amniotic fluid is able to breach the physical barrier between the maternal and fetal environments as a result of uterine trauma. These three contributory pathways are: (a) mechanical obstruction of vessels caused by AFE (b) a subsequent inflammatory effect by AFE on the maternal circulatory system and (c) an as of yet poorly understood immunologic mechanism. Pathophysiology of amniotic fluid embolismĪmniotic fluid embolism syndrome is thought to occur through three different pathophysiologic mechanisms. We also highlight the critical care aspects of affected patient care, and focus on the high index of clinical suspicion required to promptly recognize and treat this cause of 10-26% of maternal deaths. In this review we discuss the pathophysiology, clinical presentation, and diagnostic and therapeutic considerations associated with AFE. Although specialists in obstetrics are the most likely to encounter this clinical entity emergency medicine physicians, surgeons, anesthesiologists, and intensivists should also be familiar with the diagnosis and management of AFE. Due to the uncommon occurrence of AFE the need exists for a high level of clinical suspicion among practitioners. The reported incidence of AFE is between 0.001% and 0.013% among patients admitted for delivery. Its first modern description was published in the 1920's with a further report recognizing AFE as a syndrome in the 1940s.

Clinical sequelae of this unpredictable and unpreventable entity are often devastating with significant associated morbidity and mortality. The key factors for successful management and resolution of this disease process continue to be sharp vigilance, a high level of clinical suspicion, and rapid all-out resuscitative efforts on the part of all clinicians involved in the medical care of the parturient.Īmniotic fluid embolism (AFE) is a rare event that affects parturients during delivery or in the immediate postpartum period. Special attention is paid to the modern aggressive supportive care that resulted in an overall reduction in the still alarmingly high mortality rate of this devastating entity. In this review the current state of medical knowledge about AFE is outlined including its incidence, risk factors, diagnosis, pathophysiology, and clinical manifestations. However, this rare occurrence carries a high probability of serious sequelae including cardiac arrest, ARDS, coagulopathy with massive hemorrhage, encephalopathy, seizures, and both maternal and infant mortality. With its low incidence it is unlikely that any given practitioner will be confronted with a case of AFE. Amniotic fluid embolism (AFE) is an unpredictable and as-of-yet unpreventable complication of maternity.

Treatment for amniotic fluid embolism