Rapid alveolar epithelial fluid clearance following lung lavage in pulmonary alveolar proteinosis

Study objective: To measure the in vivo rate of alveolar epithelial fluid c learance of the human lung in patients with pulmonary alveolar phospholipop roteinosis (PAP). Design: Prospective clinical study. Setting: The medical-surgical ICUs of a university teaching hospital. Patients: Four patients with idiopathic PAP requiring therapeutic lung lava ge. Interventions: Large-volume lung lavage with isotonic saline solution using fiberoptic bronchoscopy followed by serial sampling of alveolar fluid usin g a wedged bronchial catheter. Measurements and results: The rate of alveolar epithelial fluid clearance w as calculated by measuring the concentration of protein in sequential sampl es. Alveolar epithelial fluid clearance over the first hour after lung lava ge was 53 +/- 14% (mean +/- SD). Sequential samples in two patients indicat ed a sustained high rate of clearance over several hours. Plasma and alveol ar fluid epinephrine levels were in the normal range in two patients. Conclusions and significance: Alveolar fluid clearance is rapid after lung lavage in patients with PAP and appears to be driven by catecholamine-indep endent mechanisms. The rapid rate of alveolar epithelial fluid transport ex plains why patients with PAP tolerate large-volume lung lavage.