Pulmonary Effects of Oxygen Breathing

Abstract

The most constant early symptom of pulmonary oxygen toxicity in normal volunteers is substernal distress, which usually develops between the 12th and 16th hours. This suggests that oxygen breathing might produce an acute tracheobronchitis. The following measurements were done in 10 normal volunteers breathing 90% to 95% oxygen to detect this possibility: [1] bronchofiberscopic observations of the trachea, [2] estimation of tracheal mucous velocity, and [3] pulmonary function tests. Endoscopic evidence of tracheitis was present in all subjects at the end of 6 hours of breathing oxygen. Tracheal mucous velocity was depressed as early as 3 hours after oxygen breathing and was the most sensitive indicator of oxygen-induced tracheitis. Administration of terbutaline, a beta adrenergic stimulant, restored tracheal mucous velocity to control levels by increasing the proportion of faster moving mucous pathways.