Multi-compartment V/Q lung modeling: Log normal distributions of inspired or expired alveolar gas?

Autor: Scott PH; Intensive Care Department, Mater Health Services, Brisbane, Queensland, Australia.; University of Queensland, Brisbane, Queensland, Australia., Morgan TJ; Mater Research and University of Queensland, Brisbane, Queensland, Australia.
Jazyk: angličtina
Zdroj: Physiological reports [Physiol Rep] 2024 Sep; Vol. 12 (17), pp. e16175.
DOI: 10.14814/phy2.16175
Abstrakt: Using a 50-compartment Python-coded mathematical lung model, we compared mixed venous blood flow (Q) distributions and arterial oxygen tension/inspired oxygen fraction (PaO 2 /FiO 2 ) relationships in lungs modeled with log normal distributions (LND) of inspired (V I ) versus expired (V A ) alveolar gas volumes. In lungs with normal V/Q heterogeneity, Q versus V A /Q and Q versus V I /Q distributions were similar with either approach, and PaO 2 /FiO 2 sequences remained indistinguishable. In V/Q heterogeneous lungs at high FiO 2 , V I LND generated low Q versus V A /Q shoulders and some negative V A units, while V A LND preserved Q versus V A /Q log normality by blood flow diversion from low V I /Q units. We managed V I LND-induced negative V A units either by shunt conversion (V I decreased to 0) or V I redistribution simulating collateral ventilation (V I increased till V A  = 0). Comparing oxygen transfer: V A LND > V I LND (redistribution) > V I LND (shunt). In V/Q heterogeneous lungs V A LND and V I LND (redistribution) regained near optimal oxygen transfer on 100% oxygen, while impairment persisted with V I LND (shunt). Unlike V A LND, V I LND (redistribution) produced Q versus V A /Q distributions in V/Q heterogeneity compatible with multiple inert gas (MIGET) reports. V I LND (redistribution) is a physiologically-based MIGET-compatible alternative to West's original V A LND lung modeling approach.
(© 2024 The Author(s). Physiological Reports published by Wiley Periodicals LLC on behalf of The Physiological Society and the American Physiological Society.)
Databáze: MEDLINE
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