Fatal postoperative pulmonary edema: pathogenesis and literature review.

STUDY OBJECTIVES

Pulmonary edema is a known postoperative complication, but the clinical manifestations and danger levels for fluid administration are not known. We studied (1) 13 postoperative patients (11 adult, 2 pediatric) who developed fatal pulmonary edema, and (2) one contemporaneous year of inpatient operations at two university teaching hospitals to determine the clinical manifestations, causes, epidemiology, and guidelines for fluid administration.

DESIGN

Retrospective analysis of 13 patients with fatal postoperative pulmonary edema and one contemporaneous year of major inpatient surgery.

PATIENTS AND METHODS

Thirteen patients had net fluid retention of at least 67 mL/kg in the initial 24 postoperative hours and developed pulmonary edema. Ten were generally healthy while three had serious associated medical conditions.

MEASUREMENTS AND RESULTS

There was no measurement, laboratory value, or clinical finding predictive of impending pulmonary edema. The most common clinical manifestation following the onset of pulmonary edema was cardiorespiratory arrest (n = 8). Patients had metabolic acidosis (pH = 7.15 +/- .33), hypoxia (PO2 = 45 +/- 18 mm Hg), and normal electrolytes. The diagnosis of pulmonary edema was established by chest radiograph and confirmed by autopsy and pulmonary artery pressure (21 +/- 4 mm Hg). The mean net fluid retention was 7.0 +/- 4.5 L (90 +/- 36 mL/kg/d) and exceeded 67 mL/kg/d in all patients. Autopsy revealed pulmonary edema with no other cause of death. Among 8,195 major operations, 7.6% developed pulmonary edema with a mortality of 11.9%. Extrapolation to the 8.2 million annual major surgeries in the United States yields a projection of 8,000 to 74,000 deaths.

CONCLUSIONS

Pulmonary edema can occur within the initial 36 postoperative hours when net fluid retention exceeds 67 mL/kg/d. There are no known predictive warning signs and cardiorespiratory arrest is the most frequent clinical presentation. The monitoring systems currently in use neither detect nor predict impending pulmonary edema, and as yet, there are no known panic values for excessive fluid administration or retention.