Carbon monoxide effect on alveolar epithelial permeability.

A carbon monoxide (CO)-intoxicated patient developed increased permeability-type pulmonary edema demonstrated by a normal capillary wedge pressure and production of protein-rich edema fluid. To investigate the effect of CO on alveolar-epithelial permeability, a radio-active labelled isotope, 51Cr-EDTA (MW 377), was instilled into the airways of rabbits. Subsequent egress of the marker from the lungs into arterial blood was determined in serial arterial blood samples. The 51Cr-EDTA counts increased significantly within 15 minutes in the CO-exposed animals, compared with the control animals, while dynamic lung compliance fell, airways resistance rose, and arterial blood pressure decreased. Ultrastructural study of the lungs of CO-exposed animals revealed epithelial and endothelial cell swelling, in terstitial edema, and alveolar type II cells depleted of lamellar bodies. These findings support the possibility that carbon monoxide intoxication is associated with increased alveolar-epithelial permeability.