PREDICTION OF DECOMPRESSION ILLNESS USING BUBBLE MODELS

Authors
  1. Tikuisis, P.
  2. Gault, K.A.
  3. Nishi, R.Y.
Corporate Authors
Defence and Civil Inst of Environmental Medicine, Downsview ONT (CAN)
Abstract
The method of maximum likelihood was applied to models of bubble formation and evolution against data involving decompression illness (DCI). Equilibrium and non-equilibrium models were tested under the constraint of a finite tissue volume. The equilibrium model (leg), where the internal gas of a bubble is in partial pressure and mechanical equilibrium with the gas dissolved in tissue, assumed formation of a bubble upon any gas supersaturation. The non-equilibrium model (neg), were the exchange of gas between the bubble and the tissue is governed by a rate constant but maitains mechanical equilibrium, assumed formation of a bubble at the metastable equilibrium state which requires a specific degree of gas supersaturation. In addition, another version of bubble evolution based on the diffusitiviy of gas in tissue (vanliew) was tested under similar finite volume constraints. Model parameters included liquid surface tension, the gas exchange rate constant, gas solubility, and the tissue time constant. The risk of DCI was based on the bubble radius (R) raised to powers ranging form 0 to 6. The data included 2023 man-dives in 630 different dive profiles of air and nitrox gas mixtures with depth ranging from 1.75 to 7.09 bars and bottom time ranging from 2.8 to 300.2 min. TRUNCATED
Keywords
Survival analysis;Critical radius
Report Number
DCIEM-93-43 — Reprint
Date of publication
31 Dec 1994
Number of Pages
15
Reprinted from
Undersea & Hyperbaric Medicine, vol 21, no 2, 1994, p 129-143
DSTKIM No
94-05006
CANDIS No
144756
Format(s):
Hardcopy;Originator's fiche received by DSIS

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