Changes in lung volume, diffusing capacity, and blood gases in men breathing oxygen.

Abstract

Four volunteers were placed in a controlled environmental chamber and breathed 98% O2 at 760 mm Hg pressure for 30, 48, 60, and 74 hr., respectively. There was a fall in vital capacity which was rapidly progressive after 60 hr. of exposure and 3 subjects exposed longer than 30 hr. had drops in pulmonary diffusing capacity. The alveolar-arterial O2 difference ranged from 59 to 121 mm Hg with an average of 89 mm Hg. Chest X-rays revealed no abnormal shadows in the lung fields and physical examination showed no apparent abnormalities. Interpreted in the light of observations in animals exposed to the same conditions, these changes are explained on the basis of alveolar edema formation and an alteration in the air-blood barrier. A 5th volunteer who breated air in the same chamber for 6 days showed no changes in lung volumes, diffusing capacity, or blood gases.