Fatal postoperative pulmonary edema - Pathogenesis and literature review

Study objectives: Pulmonary edema is a known postoperative complication, bu t the clinical manifestations and danger levels for fluid administration ar e not known. We studied (1) 13 postoperative patients (11 adult, 2 pediatri c) who developed fatal pulmonary edema, and (2) one contemporaneous ! ear o f inpatient operations at two university teaching hospitals to determine th e clinical manifestations, causes, epidemiology, and guidelines for fluid a dministration. Design: Retrospective analysis of 13 patients with fatal postoperative pulm onary edema and one contemporaneous year of major inpatient surgery. Patien ts and methods: Thirteen patients had net fluid retention of at least 67 mL /kg in the initial 24 postoperative hours and developed pulmonary edema. Te n were generally healthy while three had serious associated medical conditi ons. Measurements and results: There was no measurement, laboratory value, or cl inical finding predictive of impending pulmonary edema. The most common cli nical manifestation following the onset of pulmonary edema was cardiorespir atory arrest (n = 8). Patients had metabolic acidosis (pH = 7.15 +/- .33), hypoxia (Po-2 = 45 +/- 18 mm Hg), and normal electrolytes. The diagnosis of pulmonary edema was established by chest radiograph and confirmed by autop sy and pulmonary artery pressure (21 +/- 4 mm Hg), The mean net fluid reten tion was 7.0 +/- 4.5 L (90 +/- 36 mL/kg/d) and exceeded 67 mL/kg/d in all p atients. Autopsy revealed pulmonary edema with no other cause of death, Amo ng 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 Un ited 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 predi ctive warning signs and cardiorespiratory arrest is the most frequent clini cal presentation. The monitoring systems currently in use neither detect no r predict impending pulmonary edema, and as yet, there are no known panic v alues for excessive fluid administration or retention.