Postobstructive pulmonary edema is a well-recognized complication of upper airway obstruction. The mechanisms of edema formation are unclear and may be due to increased hydrostatic forces generated by high negative inspiratory pressure or by increased permeability of the alveolar capillary membrane. Measurement of the edema fluid/plasma protein ratio and the rate of net alveolar fluid clearance are two well-validated methods for classifying the underlying mechanism of edema formation. The goal of the current study was to investigate the mechanisms of pulmonary edema formation in patients with postobstructive pulmonary edema by serial sampling of undiluted pulmonary edema fluid.
