What is the diagnosis and treatment for Amniotic Fluid Embolism (AFE)?

From the Guidelines

Amniotic fluid embolism (AFE) should be considered in the differential diagnosis of sudden cardiorespiratory compromise in any pregnant or recently postpartum patient, and management should include immediate high-quality cardiopulmonary resuscitation with standard basic cardiac life support and advanced cardiac life support protocols 1. The diagnosis of AFE is primarily clinical, and no specific diagnostic laboratory test is recommended to confirm or refute the diagnosis 1.

Key Management Strategies

• Immediate resuscitation efforts with oxygenation and ventilation support
• Fluid resuscitation with crystalloids
• Vasopressors such as norepinephrine or epinephrine for hemodynamic stabilization
• Blood product replacement with massive transfusion protocols
• Correction of coagulopathy with fibrinogen concentrate or tranexamic acid
• Early involvement of a multidisciplinary team including obstetrics, anesthesia, critical care, and hematology

Clinical Presentation

AFE typically presents during labor, delivery, or immediately postpartum with sudden onset of hypoxia, hypotension, and coagulopathy 1.

Pathophysiology

AFE occurs when amniotic contents breach the maternal-fetal barrier, activating inflammatory mediators and complement, leading to anaphylactoid reaction, pulmonary vasoconstriction, and disseminated intravascular coagulation 1.

Prognosis

Despite optimal management, mortality remains high at 20-40%, making rapid recognition and aggressive supportive care the cornerstone of treatment 1.

Recommendations

• Consideration of AFE in the differential diagnosis of sudden cardiorespiratory collapse in the laboring or recently delivered woman (GRADE 1C) 1
• Provision of immediate high-quality cardiopulmonary resuscitation with standard basic cardiac life support and advanced cardiac life support protocols in patients who develop cardiac arrest associated with AFE (GRADE 1C) 1
• Involvement of a multidisciplinary team including anesthesia, respiratory therapy, critical care, and maternal-fetal medicine in the ongoing care of women with AFE (Best Practice) 1

From the Research

Diagnosis of Amniotic Fluid Embolism (AFE)

• The diagnosis of AFE is based on the presence of acute respiratory distress, cardiovascular collapse, and coagulopathy, with the hallmark triad of symptoms being acute respiratory distress, cardiovascular collapse, and coagulopathy 2
• Four diagnostic criteria proposed by the Society for Maternal-Fetal Medicine (SMFM) may accelerate diagnosis, including sudden onset of hypotension or hypoxia, respiratory distress, and either consumptive coagulopathy or severe bleeding 3
• Laboratory tests may reveal severe anemia, thrombocytopenia, coagulopathy, severe acidosis, and myocardial injury, while histopathology can confirm the presence of amniotic fluid components in the embolism 4

Treatment of Amniotic Fluid Embolism (AFE)

• The initial immediate response to AFE should be to provide high-quality cardiopulmonary resuscitation, with priorities including thromboelastography interpretation, control of hemorrhage and coagulopathy with blood component therapy, and cardiovascular support through inotropes and vasopressor administration 5, 2
• Treatment for coagulopathy should be initiated promptly, with the use of a 1:1:1 ratio of packed red cells, fresh frozen plasma, and platelets, and cryoprecipitate as needed to maintain a serum fibrinogen of >150-200 mg/dL 5
• Venoarterial extracorporeal membrane oxygenation (VA-ECMO) may be considered in cases that require prolonged cardiopulmonary resuscitation or severe ventricular dysfunction refractory to medical management, as it provides support for end-organ perfusion in place of the weakened and recovering heart while optimizing oxygenation 5, 4, 2
• Early implementation of extracorporeal cardiopulmonary resuscitation (ECPR) during the acute phase of AFE can provide support for end-organ perfusion, making VA-ECMO an ideal adjunctive therapy 2