Hyperbaric and Hyperoxic Effects on Pulmonary Function During Air Saturation Dives

Abstract

Three saturation dive profiles (11 separate dives) utilizing a total of 35 human subjects were completed. They were AIRSAT-1 (2.82 ATA air saturation, five 8-hour excursions to 4.03 ATA) , AIRSAT-2 (2.82 ATA air saturation, six 2-hour excursions to 5.55 ATA), and AIRSAT-3 (0.3 ATA 0(2) at 5 ATA, three 5-hour air excursions to 7 ATA). AIRSAT-3 involved a 24 hour exposure to 5 ATA air prior to decompression. Pulmonary function was measured in all subjects throughout the exposures. Signs and symptoms of pulmonary oxygen toxicity and significant decreases in forced vital capacity and single breath diffusing capacity were observed. Marked individual variability was apparent in all exposures. Air at 2.82 ATA (60 fswg, 0.59 ATA 0(2)) is very close to the oxygen toxicity threshold, and air at 5.00 ATA (132 fswg, 1.05 ATA 0(2)) is well beyond it.