A Statistical Analysis of Recent Naval Experimental Diving Unit (NEDU) Single-Depth Human Exposures to 100% Oxygen at Pressure.

Abstract

Using the data from 688 human single-depth hyperbaric oxygen (02) exposures conducted at the Naval Experimental Diving Unit and reported on from 1979-1986, we developed a mathematical model that can predict the risk of developing symptoms of central nervous system 02 toxicity as a function of time and depth of exposure. Maximum likelihood analysis with models relating depth and time of exposure to risk accumulation was used to estimate probability of symptom development and confidence intervals. U.S. Navy single depth-time 02 diving limits were evaluated for safety as a function of actual P02 achieved in the breathing apparatus. These results suggest that current limits are not of equal risk. Long shallow exposures might present unacceptably high risk if an F102 = 1.0 were achieved in the breathing rig. Adherence to current recommended purging procedures results in acceptably low (< 1%) risk predictions for all depths.