[abstract] A MATHEMATICAL MODEL OF DIFFUSION-LIMITED BUBBLE GROWTH IN UNSTIRRED TISSUE OF FINITE VOLUME.

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[abstract] A MATHEMATICAL MODEL OF DIFFUSION-LIMITED BUBBLE GROWTH IN UNSTIRRED TISSUE OF FINITE VOLUME.

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Title: [abstract] A MATHEMATICAL MODEL OF DIFFUSION-LIMITED BUBBLE GROWTH IN UNSTIRRED TISSUE OF FINITE VOLUME.
Author: Srinivasan, RS; Gerth, WA; Powell, MR
Abstract: BACKGROUND: In a two-region description of gas bubble dynamics, the volume of the unstirred tissue surrounding the gas bubble is infinite (J. Appl. Physiol. 86: 732-741,1999). Models based on such a description cannot accommodate multiple bubbles with possible interactions among them. This paper presents a model in which the unstirred diffusion region around the bubble has a finite volume. METHODS: We modified the two-region model with infinite tissue volume by introducing deviations in tissue gas tension to obtain a zero concentration gradient, and hence zero gas flux, at any finite distance from the bubble. Diffusion-limited gas exchange between bubble and tissue is driven by a difference between bubble gas pressure and an average tissue gas tension that explicitly depends on gas uptake by the bubble. Bubble evolutions from an initial critical size in a hypothetical altitude decompression profile were simulated using the model with physiologically reasonable parameter values. RESULTS: A typical model-generated radius-time profile is shown in the figure (page 24 of the supplement). Compared to previous models, the present model generally yields smaller maximum bubble radii, but longer bubble lifetimes. For example, with a tissue halftime of 150 min, and diffusivity of 18 um^2/min, the bubble persists longer than 7 hours. CONCLUSION: The new model has one less adjustable parameter because the diffusion region is defined by a zero concentration gradient at its outer boundary. Thus, it is computationally simpler for use in risk functions to predict the probability of decompression sickness (DCS) in human subjects.
Description: Undersea and Hyperbaric Medical Society, Inc. (http://www.uhms.org)
URI: http://archive.rubicon-foundation.org/6442
Date: 2000

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  • UHMS Meeting Abstracts
    This is a collection of the published abstracts from the Undersea and Hyperbaric Medical Society (UHMS) annual meetings.

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