Pulmonary Effects of Eight Hours Underwater Breathing 1.35 ATM Oxygen: 100% Oxygen or 16% Nitrogen, 84% Oxygen

摘要

To investigate how 16% nitrogen in the breathing gas affects pulmonary oxygen toxicity when Po2 is held at 1.35 atmospheres, 31 U.S. Navy divers dove underwater in the Ocean Simulation Facility of the Navy Experimental Diving Unit (NEDU) at 20 feet of seawater with 16% N2, 84% O2 as the breathing gas, and 23 divers breathing 100% O2 dove in the NEDU test pool. Dives were 8 hours long at water temperatures of 88 plus or minus 5 degrees F and with humidified gas; divers were resting and were allowed air breaks of 5 minutes every hour. Pulmonary function and respiratory symptoms were assessed before and after diving and were compared between conditions. The incidences of changes in pulmonary function at any time measured, symptoms during dives, and symptoms on surfacing did not differ between conditions, but symptoms one or more days after diving were fewer after mixed gas diving than after 100% O2 diving. Pulmonary oxygen toxicity with 16% N2 in the breathing gas is not reduced from that with 100% O2 at the same partial pressure.