Rapid diagnosis of amniotic fluid embolism.

Acute respiratory failure developed in a 19-year-old primigravida 7 hours after undergoing cesarean section. The diagnosis of amniotic fluid embolism was established by viewing fragments of vernix caseosa in a pulmonary artery blood sample. Forty-eight hours after the cytologic diagnosis had been made, amniotic fluid material was no longer present in pulmonary arterial blood. The patient underwent supportive care in an intensive care setting and recovered completely.