MODEL SIMULATIONS OF GAS MIXING AND VENTILATION DISTRIBUTION IN THE HUMAN LUNG

Sylvia Verbanck, M. Paiva

Research output: Contribution to journalArticle

90 Citations (Scopus)

Abstract

Abstract

A new lung model that incorporates intra-acinar diffusion- and convection-dependent inhomogeneities (DCDI) and interregional and intraregional convection-dependent inhomogeneities (CDI) is described. The model is divided into two regions, each containing two subunits. Each of the four subunits in the model consists of a multi-branch-point structure, based on the anatomic data from Haefeli-Bleuer and Weibel (Anat. Record 220: 401-414, 1988). The subunit turnover (TO), i.e., the ratio of subunit tidal to resting volume, and the flow sequences (FS) between the subunits are used as model parameters. The model simulates the normalized alveolar slope (S(n)), Fowler and Bohr dead space (VD(F) and VD(B), and alveolar mixing efficiency (AME) as a function of breath number (n) during a multiple-breath N2 washout (MBNW). For the first breath of the MBNW, these indexes are poorly sensitive to the TO distribution or FS between the subunits. However, as the washout proceeds, the n dependence of both S(n) and VD(B) becomes markedly distinct for simulations with different TO and FS. VD(F) increases only slightly with n during the MBNW for a large range of TO and FS combinations, and AME is independent of FS. Comparison of published experimental observations with model simulations gave a consistent picture of ventilation maldistribution in the human lung. MBNW simulations in conditions of weightlessness, which will be performed shortly in Spacelab, suggest that it will be possible to evaluate quantitatively the intraregional elastic inhomogeneities in the human lung.
Original languageEnglish
Pages (from-to)2269-2279
Number of pages11
JournalJournal of Applied Physiology
Volume69
Issue number6
Publication statusPublished - Dec 1990

Keywords

  • MULTI-BRANCH-POINT MODELS
  • MULTIPLE-BREATH WASHOUT MANEUVERS
  • NORMALIZED SLOPE
  • FOWLER AND BOHR DEAD SPACE
  • ALVEOLAR MIXING EFFICIENCY

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