[abstract] PROGRESS OF AN AIR SATURATION DIVE SERIES: AIRSAT

Abstract

This laboratory has been conducting simulated saturation dives in air and nitrox to provide data which may help predict and deal with medical problems in submarine rescue and other operational scenarios. The anticipated medical problems include: pulmonary oxygen toxicity, decompression sickness, exercise intolerance and narcosis. The experimental dive series, AIRSAT, began in 1977 and is still in progress, with 32 man dives completed to date. AIRSAT I&II involved saturation at 2.8 ATA in air, excursions to 100 & 150 FSW, and decompression via a 20 hr. schedule. AIRSAT III utilized a saturation depth of 5 ATA in air and nitrox (ppO2 = 0.3 ATA), with air excursions to 7 ATA. AIRSAT III decompression followed the standard U.S.Navy HeO2 saturation schedule. Pulmonary function, exercise tolerance, psychomotor capability, hematologic and biochemical indices, and general medical well being were followed closely. Results and conclusions thus far are: a) continuous exposure to 2.8 ATA air produced a persistent, significant FVC decrement in about 10% of subjects; and a small early transient drop in most subjects; b) 24 hr. exposure to 5 ATA air and subsequent air decompression produced a significant FVC decrement in about 30% of subjects; c) saturation decompression from 2.8 ATA air on the 20 hr. table produced 1 case of type I DCS out of 23 subjects; and decompression from 5 ATA air on the standard HeO2 schedule yielded 1 case of type I DCS out of 9 subjects; d) maximal exercise in air at 5 or 7 ATA air was impaired minimally; e) narcosis was apparent at 5 and 7 ATA, and although there was improvement in psychomotor capability with time at depth, the subjects never reached their baseline performance; f)previously reported changes in electrolytes, iron metabolism, and red cell mass were confirmed; g) no post-dive medical problems were noted.