Acute circulatory and respiratory collapse in obstetrical patients: a case report and review of the literature.

Venous air embolism is the entrapment of air into the venous system producing signs and symptoms due to obstruction of pulmonary arterial blood flow. We present a healthy, 27-year-old, full-term parturient admitted for postdate induction of labor. Cesarean delivery was required following fetal distress. During delivery, the mother became bradycardic and required advanced cardiac life support for resuscitation. Serial hemoglobin values, electrocardiograms, echocardiograms, and a magnetic resonance image of the head were all normal. No fetal squamous cells were found in the patient's blood. She required 6 days of ventilation, was successfully extubated, and was discharged 14 days after the cesarean delivery. The differential diagnosis in this patient's care centered on a pulmonary embolic event. Thromboembolism was unlikely, based upon the patient's rapid clinical improvement without definitive therapy for thrombotic disease or detection of peripheral thrombosis. Amniotic fluid embolus was unlikely, although not excluded, by the absence of fetal cells in the maternal circulation and the lack of an accompanying intravascular coagulopathy. Air embolism may occur in up to 50% of women undergoing cesarean delivery. A lethal embolism may follow a bolus of 3 to 5 mL/kg of air. Chief among the many symptoms of air embolism are tachypnea, chest pain, and gasping. The diagnosis may be facilitated by precordial Doppler monitoring, transesophageal echocardiography, or by the identification of air when aspirating from a right heart catheter. Management includes optimum patient positioning, aspiration of air, discontinuation of nitrous oxide, administration of 100% oxygen, and flooding the surgical site with saline to avoid further air entry. Preventive strategies are also discussed.