Discussion
AFE is a rare complication but has high fatality rate, characterized by sudden cardiovascular collapse, dyspnea or respiratory collapse and disseminated intravascular coagulopathy[4]. This may occur in healthy women during pregnancy, labor or following delivery. It can develop even after elective abortion, amniocentesis, cesarean delivery or trauma. This condition is initiated by entry of amniotic fluid to the blood stream of the mother which leads a serious reaction causing cardiopulmonary arrest and massive coagulopathy[3][5].
Because AFE is a diagnosis of exclusion, a precise case definition and criteria is difficult to establish and also other causes of maternal collapse should be ruled out. The causes of maternal collapse could be due to hemorrhagic shock, pulmonary embolism, anaphylaxis, septic shock, aortic dissection [6]. Diagnosis is based upon the signs and symptoms observed during the birth or procedure.
The associated risk factors for AFE are age more than 35 years, multiparity, cesarean section, instrumental delivery, antepartum hemorrhage, eclampsia, labor induction, fetal distress, fetal death, male baby [7][8] [9].
Few authors have proposed two clinical forms of AFE typical and atypical. Typical or classic form has three phases: phase 1 – respiratory and circulatory disorders, phase 2- coagulation disturbances and phase 3 -acute renal failure and acute respiratory distress syndrome(ARDS) leading to cardiopulmonary collapse[10]. In Atypical form, cardiopulmonary collapse doesn’t occur but first symptom is life threatening hemorrhage due to DIC[11].
The most significant diagnosis of AFE is made by findings at autopsy, which are limited to the lungs and clinical diagnostic criteria, and assisted by serum markers[12]. Serum markers like C3, C4 and C1 esterase inhibitors are reduced.
The symptoms are usually sudden in onset. Acute dyspnea, agitation, sudden chills, sweating coughing and anxiety are common premonitory symptoms. Labored breathing and tachypnea may occur. Diagnosis can be made by following criteria[2][13],
  1. Acute hypotension or cardiac arrest
  2. Acute hypoxia
  3. Coagulopathy or severe hemorrhage in the absence of other explanations
  4. All of these occurring during labor, cesarean delivery, dilation and evacuation or within 30 minute postpartum with no other explanation of findings.
In our case, this women had risk factor of fetal death and labor induction. She didn’t have fever, obstetric hemorrhage, eclampsia or any other identifiable cause of postpartum collapse and also, she fitted to the above mentioned criteria of AFE, hence we had made diagnosis of AFE.
The initial phase of AFE consists mainly of right ventricular failure. If available, transthoracic and or transesophageal echocardiography may provide valuable information. Immediately after presentation, the echocardiography will reveal a severely dilated hypokinetic right ventricle (acute Cor pulmonale) with deviation of the interventricular septum in to the left ventricle. In our case transthoracic echocardiography was done on 3rd day which showed mild mitral regurgitation, mild pulmonary artery hypertension without any vegetation and clots. As patient was already stabilized, finding may not be suggestive of AFE or pulmonary embolism. Also, early and aggressive resuscitation with blood product to correct coagulopathy results in improved outcomes[14].
As computed tomography angiography or ventilation perfusion scan is not available in our center, we were not able to perform this test, which could have been performed to rule out pulmonary embolism. As this patient had coagulopathy, acute hypoxia and maternal collapse which is in favor of AFE than pulmonary embolism.
Survival after AFE has improved significantly due to early recognition and management, morbidity remains high with severe sequelae. Neurological impairment is most common complication followed by renal failure, cardiac failure with left ventricular impairment, arrythmia have been reported [8].
Primary management is respiratory support and hemodynamic support with judicious use of fluids, vasopressors, inotropes and pulmonary vasodilators. Early diagnosis and aggressive management of patient with resuscitation improves the survival as well as long term morbidities.