Amniotic Fluid Embolism (AFE)

Definition

Amniotic Fluid Embolism (AFE) is a rare but life-threatening condition characterized by the entry of fetal cells, lanugo, and other debris from the amniotic fluid into the maternal circulation. This condition can lead to severe respiratory, cardiovascular, and hematological complications.

Pathophysiology

The pathogenesis of AFE involves several key steps:

• Fetal cells and debris embolize to the pulmonary arterioles, causing increased pulmonary arterial pressure, right heart failure, and pulmonary edema.
• Procoagulants from amniotic fluid enter maternal circulation, triggering diffuse intravascular coagulation (DIC).
• Leukotrienes from amniotic fluid initiate an immune response, leading to pulmonary vasospasm and alveolar capillary damage.

Risk Factors

• Maternal age over 30 years.
• Multiparity.
• Complicated labor, including conditions like placenta previa/abruption, eclampsia, or the need for forceps delivery or cesarean section.
• Invasive procedures such as amniocentesis or certain types of abortion.
• Blunt abdominal trauma.

Clinical Features

AFE typically occurs during labor or within 48 hours postpartum, manifesting as:

• Acute respiratory distress syndrome (ARDS), marked by dyspnea, tachypnea, hypoxia, and cyanosis.
• Cardiovascular collapse, including hypotension, arrhythmias, and cardiac arrest.
• Neurological symptoms such as altered mental status and seizures.
• Signs of DIC, including anemia and thrombocytopenia.
• Multiorgan dysfunction and fetal distress.

Diagnosis

AFE is primarily diagnosed based on clinical presentation, particularly the sudden onset of hypoxia, hypotension, and coagulopathy during or shortly after labor. Laboratory studies supportive of the diagnosis include arterial blood gas analysis revealing hypoxemia, coagulation studies indicating DIC, and pulmonary artery blood samples showing fetal debris. However, treatment should not be delayed for diagnostic confirmations.

Management

Immediate management of AFE includes:

• ABCDE survey with respiratory and hemodynamic support.
• Emergency delivery if necessary.
• CPR with consideration for perimortem cesarean delivery.
• Treatment of DIC and management of refractory uterine bleeding.

Prognosis

AFE carries a high maternal mortality rate and can result in significant neurological deficits in surviving infants. Early recognition and aggressive management are crucial to improving outcomes.

Conclusion

Amniotic Fluid Embolism is a complex, emergent condition requiring prompt diagnosis and multidisciplinary management to mitigate its life-threatening complications. Awareness of its risk factors, clinical presentation, and management strategies is essential for healthcare providers involved in peripartum care.