Accession Number : ADA308247

Title :   Statistically Based Decompression Tables IX: Probabilistic Models of the Role of Oxygen in Human Decompression Sickness.

Descriptive Note : Technical rept. Jan 91-Dec 93,

Corporate Author : NAVAL MEDICAL RESEARCH INST BETHESDA MD

Personal Author(s) : Parker, E. C. ; Survanshi, S. S. ; Thalmann, E. D. ; Weathersby, P. K.

PDF Url : ADA308247

Report Date : MAR 1996

Pagination or Media Count : 37

Abstract : While probabilistic models of human decompression sickness (DCS) have been successful in describing both the level and timing of DCS risk in a wide variety of N2-O2 data, they have failed to account for the observed DCS risk in the currently available collection of dives with significant periods of 100% oxygen breathing. The best model to date, calibrated with over 2300 air and N2-O2 dives, under-predicts the DCS risk of these O2 dives by 60%, whether O2 is breathed during in-water decompression or during surface decompression procedures. This overestimation of the benefit of 0 is due to an exaggerated acceleration of N2 wash-out during 02 breathing. Seven-hundred and twenty-nine 02 decompression and surface decompression dives were added to the calibration data set. Fitting the existing base model to the new combined data set resulted in some improvement in OCS prediction n 02 data, but DCS predictions remained about 30% below the observed level. Three classes of 02-specific modifications to the base model were proposed: (1) modification of inert gas kinetics as a function of 02 pressure, (2) direct contribution of DCS risk as a function of either O pressure or fraction.

Descriptors :   *OXYGEN, *DIVING, *DECOMPRESSION SICKNESS, *BREATHING APPARATUS, DATA BASES, RISK, PREDICTIONS, MODELS, HUMANS, PROBABILITY, GASES, SHORT RANGE(TIME), SURFACES, MILITARY MEDICINE, KINETICS, INERT MATERIALS, MEDICAL RESEARCH, INTERVALS.

Subject Categories : Stress Physiology
      Marine Engineering

Distribution Statement : APPROVED FOR PUBLIC RELEASE