Accession Number:

ADA257613

Title:

Statistically Based Decompression Tables 8: Linear-Exponential Kinetics.

Descriptive Note:

Technical rept. Aug 90-Oct 91,

Corporate Author:

NAVAL MEDICAL RESEARCH INST BETHESDA MD

Report Date:

1992-09-01

Pagination or Media Count:

62.0

Abstract:

Probabilistic models applied to diving decompression data have been successful in describing decompression sickness DCS occurrence and even time of DCS occurrence. This study explores a class of models using linear as well as exponential gas exchange kinetics to provide slower tissue washout than previous models. The models consist of 3 or 4 kinetic compartments, each of which can employ purely exponential EE or mixed linear-exponential LE kinetics. The risk of DCS is obtained from the single or double integration of the sum of compartment over-pressures. The resulting four models, EE1, EE2, LE1, and LE2 cover a broad range of gas kinetic possibilities. The data used in fitting these models are compiled from U.S. Navy, Canadian, and British chamber dive trials. There are 799 different dive profiles, representing 2383 man-dives, with a DCS incidence of 5.8 131 DCS cases, 75 marginal cases. Time of DCS occurrence information is included for all decompression sickness, maximum likelihood, probabilistic modelling, gas exchange kinetics. DCS and many marginal cases. Maximum Likelihood fitting of the four models to these data indicate LE1 to be the best fit. The LE1 Model is able to predict DCS occurrence in the fitted data, as categorized by type of dive profile, risk level, and time of DCS occurrence. LE1 is able to predict DCS occurrence well in most data not used for fitting, with the exception of profiles using high percentage O2 breathing mixtures and some repetitive profiles.

Subject Categories:

  • Medicine and Medical Research
  • Stress Physiology
  • Numerical Mathematics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE