Alveolar epithelial fluid transport and the resolution of severe hydrostatic pulmonary edema: a study of ventilated, critically ill patients. Verghese, G. M., Ware, L. B., Matthay, B. A. and Matthay, M. A. Departments of Medicine and Anesthesia, and the Cardiovascular Research Institute, University of California, San Francisco, California 94143-0130
APStracts 6:0261A, 1999.
In order to characterize the rate and regulation of alveolar fluid clearance in the uninjured human lung, pulmonary edema fluid and plasma were sampled within the first 4 h after tracheal intubation in 65 mechanically ventilated patients with severe hydrostatic pulmonary edema. Alveolar fluid clearance was calculated from the change in pulmonary edema fluid protein concentration over time. Overall, 75% of patients had intact alveolar fluid clearance (>/= 3%/h). Maximal alveolar fluid clearance (>/= 14%/h) was present in 38% of patients with a mean rate of 25 +/- 12%/h. Hemodynamic factors (including pulmonary artery wedge pressure and left ventricular ejection fraction) and plasma epinephrine levels did not correlate with impaired or intact alveolar fluid clearance. Impaired alveolar fluid clearance was associated with a lower arterial pH and a higher Simplified Acute Physiology Score (SAPS II). These factors may be markers of systemic hypoperfusion, which has been reported to impair alveolar fluid clearance by oxidant mediated mechanisms. Finally, intact alveolar fluid clearance was associated with a greater improvement in oxygenation at 24 h along with a trend toward shorter duration of mechanical ventilation and an 18% lower hospital mortality. In summary, alveolar fluid clearance in humans may be rapid in the absence of alveolar epithelial injury. Catecholamine -independent factors are important in the regulation of alveolar fluid clearance in patients with severe hydrostatic pulmonary edema. 

Received 5 February 1999; accepted in final form 9 June 1999.
APS Manuscript Number A083-9.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1999 The American Physiological Society.
Published in APStracts on 22 June 1999