Pulmonary edema fluid. Spectrum of features in 37 patients.

Abstract

Pulmonary edema fluid was collected in 37 patients with fulminant pulmonary edema. Edema fluid (EF) and plasma (P) were assayed for colloid osmotic pressure (COP), total protein, osmolality and Na. Electrophoresis of EF and P was determined in 16 patients. In 22 patients, multiple causes (MC group) of edema were implicated in each patient, including shock, aspiration, bacteremia, near-drowning, coagulopathy, drug overdose and pulmonary embolism. Left ventricular failure (LVF) was also a contributing factor in some of these patients. The LVF group consisted of 15 other patients in whom LVF and/or volume overload was the primary cause of edema. The EF/P COP ratio for the MC group was 0.54-1.32 (mean .+-. SD 0.91 .+-. 0.19) and was significantly higher (P < 0.001) than that in the LVF group (range 0.28-0.69, mean .+-. SD 0.51 .+-. 0.14). In the MC group the duration of EF production was 200 .+-. 433 min, oxygenation was poor (mean arterial/alveolar O2 tension index 0.16 .+-. 0.08) and survival rate was 27%. In the LVF group the duration was 40 .+-. 47 min, oxygenation was moderately reduced (mean .+-. SD 0.38 .+-. 0.19) and the survival rate was 66%. In most cases when the EF/P protein ratio was high, proportionately less albumin than globulin was found in EF. Apparently when a high content of protein is found in EF, the pulmonary microvascular membrane is damaged and edema is more severe (permeability pulmonary edema). The wide range of ratios and clinical findings in the MC group suggest that there is a spectrum of pulmonary membrane damage that may be complicated by LVF and/or volume overload. When edema results primarily from high pressure, the membrane remains an effective barrier to protein.