In:
Journal of Applied Physiology, American Physiological Society, Vol. 86, No. 1 ( 1999-01-01), p. 273-284
Abstract:
We reported changes in alveolar-arterial Po 2 gradient, ventilation-perfusion heterogeneity, and arterial-alveolar Pco 2 gradient during partial liquid ventilation (PLV) in healthy piglets (E. A. Mates, P. Tarczy-Hornoch, J. Hildebrandt, J. C. Jackson, and M. P. Hlastala. In: Oxygen Transport to Tissue XVII, edited by C. Ince. New York: Plenum, 1996, vol. 388, p. 585–597). Here we develop two mathematical models to predict transient and steady-state (SS) gas exchange conditions during PLV and to estimate the contribution of diffusion limitation to SS arterial-alveolar differences. In the simplest model, perfluorocarbon is represented as a uniform flat stirred layer and, in a more complex model, as an unstirred spherical layer in a ventilated terminal alveolar sac. Time-dependent solutions of both models show that SS is established for various inert and respiratory gases within 5–150 s. In fluid-filled unventilated terminal units, all times to SS increased sometimes by hours, e.g., SF 6 exceeded 4 h. SS solutions for the ventilated spherical model predicted minor end-capillary disequilibrium of inert gases and significant disequilibrium of respiratory gases, which could explain a large portion of the arterial-alveolar Pco 2 gradient measured during PLV (14). We conclude that, during PLV, diffusion gradients for gases are generally small, except for CO 2 .
Type of Medium:
Online Resource
ISSN:
8750-7587
,
1522-1601
DOI:
10.1152/jappl.1999.86.1.273
Language:
English
Publisher:
American Physiological Society
Publication Date:
1999
detail.hit.zdb_id:
1404365-8
SSG:
12
SSG:
31
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