Pulmonary edema in a woman following fetal surgery.

Most cases of acute lung injury in pregnancy are attributed to hydrostatic pulmonary edema. In this report, however, we describe a 20-year-old pregnant woman who developed a unique case of increased permeability pulmonary edema following surgery for the repair of a fetal congenital diaphragmatic hernia. Two days after surgery, the patient developed acute respiratory failure and diffuse alveolar edema, requiring intubation and positive pressure ventilation for 5 days. The diagnosis of increased permeability pulmonary edema was confirmed by the ratio of pulmonary edema fluid to plasma protein (ratio=0.99). The patient received IV nitroglycerine for tocolysis. As a nitric oxide donor, the nitroglycerine may have combined with exogenous oxygen to form peroxynitrite, a known impediment to alveolar epithelial cell function. Many cases of pulmonary edema in pregnancy are diagnosed as hydrostatic based on clinical parameters, such as positive maternal fluid balance. In this case, these parameters would have been misleading. Measurement of the protein concentration in the pulmonary edema fluid allowed us to accurately determine that the patient had increased permeability pulmonary edema as the cause of her acute respiratory failure. Sampling of pulmonary fluid can differentiate the type of edema formation and in some cases help to identify mechanisms of acute lung injury.