A tidally breathing model of ventilation, perfusion and volume in normal and diseased lungs

J. S. Yem; M. J. Turner; A. B. Baker; I. H. Young; A. B.H. Crawford

doi:10.1093/bja/ael216

A tidally breathing model of ventilation, perfusion and volume in normal and diseased lungs

J. S. Yem, M. J. Turner^*, A. B. Baker, I. H. Young, A. B.H. Crawford

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

18 Citations (Scopus)

Abstract

Background. To simulate the short-term dynamics of soluble gas exchange (e.g. CO ₂ rebreathing), model structure, ventilation-perfusion ( Vdot _A/Q̇) and ventilation-volume (V̇/V_A) parameters must be selected correctly. Some diseases affect mainly V̇_A/V_A distribution while others affect both V̇_A/Q̇ and V̇_A/V_A distributions. Results from the multiple inert gas elimination technique (MIGET) and multiple breath nitrogen washout (MBNW) can be used to select V̇_AQ̇ and V̇_A/V_A parameters, but no method exists for combining V̇_AQ̇ and V̇_A/ V_A parameters in a multicompartment lung model. Methods. We define a tidally breathing lung model containing shunt and up to eight alveolar compartments. Quantitative and qualitative understanding of the diseases is used to reduce the number of model compartments to achieve a unique solution. The reduced model is fitted simultaneously to inert gas retentions calculated from published V̇_A/Q̇ distributions and normalized MBNWs obtained from similar subjects. Normal lungs and representative cases of emphysema and embolism are studied. Results. The normal, emphysematous and embolism models simplify to one, three and two alveolar compartments, respectively. Conclusions. The models reproduce their respective MIGET and MBNW patient results well, and predict disease-specific steady-state and dynamic soluble and insoluble gas responses.

Original language	English
Pages (from-to)	718-731
Number of pages	14
Journal	British Journal of Anaesthesia
Volume	97
Issue number	5
DOIs	https://doi.org/10.1093/bja/ael216
Publication status	Published - Nov 2006
Externally published	Yes

Keywords

Modelling
Ventilation inhomogeneity
Ventilation/perfusion distribution

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@article{831510c5c4d247d4b76e7655de11d15f,

title = "A tidally breathing model of ventilation, perfusion and volume in normal and diseased lungs",

abstract = "Background. To simulate the short-term dynamics of soluble gas exchange (e.g. CO 2 rebreathing), model structure, ventilation-perfusion ( Vdot A/{\.Q}) and ventilation-volume ({\.V}/VA) parameters must be selected correctly. Some diseases affect mainly {\.V}A/VA distribution while others affect both {\.V}A/{\.Q} and {\.V}A/VA distributions. Results from the multiple inert gas elimination technique (MIGET) and multiple breath nitrogen washout (MBNW) can be used to select {\.V}A{\.Q} and {\.V}A/VA parameters, but no method exists for combining {\.V}A{\.Q} and {\.V}A/ VA parameters in a multicompartment lung model. Methods. We define a tidally breathing lung model containing shunt and up to eight alveolar compartments. Quantitative and qualitative understanding of the diseases is used to reduce the number of model compartments to achieve a unique solution. The reduced model is fitted simultaneously to inert gas retentions calculated from published {\.V}A/{\.Q} distributions and normalized MBNWs obtained from similar subjects. Normal lungs and representative cases of emphysema and embolism are studied. Results. The normal, emphysematous and embolism models simplify to one, three and two alveolar compartments, respectively. Conclusions. The models reproduce their respective MIGET and MBNW patient results well, and predict disease-specific steady-state and dynamic soluble and insoluble gas responses.",

keywords = "Modelling, Ventilation inhomogeneity, Ventilation/perfusion distribution",

author = "Yem, {J. S.} and Turner, {M. J.} and Baker, {A. B.} and Young, {I. H.} and Crawford, {A. B.H.}",

year = "2006",

month = nov,

doi = "10.1093/bja/ael216",

language = "English",

volume = "97",

pages = "718--731",

journal = "British Journal of Anaesthesia",

issn = "0007-0912",

publisher = "Oxford University Press",

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TY - JOUR

T1 - A tidally breathing model of ventilation, perfusion and volume in normal and diseased lungs

AU - Yem, J. S.

AU - Turner, M. J.

AU - Baker, A. B.

AU - Young, I. H.

AU - Crawford, A. B.H.

PY - 2006/11

Y1 - 2006/11

N2 - Background. To simulate the short-term dynamics of soluble gas exchange (e.g. CO 2 rebreathing), model structure, ventilation-perfusion ( Vdot A/Q̇) and ventilation-volume (V̇/VA) parameters must be selected correctly. Some diseases affect mainly V̇A/VA distribution while others affect both V̇A/Q̇ and V̇A/VA distributions. Results from the multiple inert gas elimination technique (MIGET) and multiple breath nitrogen washout (MBNW) can be used to select V̇AQ̇ and V̇A/VA parameters, but no method exists for combining V̇AQ̇ and V̇A/ VA parameters in a multicompartment lung model. Methods. We define a tidally breathing lung model containing shunt and up to eight alveolar compartments. Quantitative and qualitative understanding of the diseases is used to reduce the number of model compartments to achieve a unique solution. The reduced model is fitted simultaneously to inert gas retentions calculated from published V̇A/Q̇ distributions and normalized MBNWs obtained from similar subjects. Normal lungs and representative cases of emphysema and embolism are studied. Results. The normal, emphysematous and embolism models simplify to one, three and two alveolar compartments, respectively. Conclusions. The models reproduce their respective MIGET and MBNW patient results well, and predict disease-specific steady-state and dynamic soluble and insoluble gas responses.

AB - Background. To simulate the short-term dynamics of soluble gas exchange (e.g. CO 2 rebreathing), model structure, ventilation-perfusion ( Vdot A/Q̇) and ventilation-volume (V̇/VA) parameters must be selected correctly. Some diseases affect mainly V̇A/VA distribution while others affect both V̇A/Q̇ and V̇A/VA distributions. Results from the multiple inert gas elimination technique (MIGET) and multiple breath nitrogen washout (MBNW) can be used to select V̇AQ̇ and V̇A/VA parameters, but no method exists for combining V̇AQ̇ and V̇A/ VA parameters in a multicompartment lung model. Methods. We define a tidally breathing lung model containing shunt and up to eight alveolar compartments. Quantitative and qualitative understanding of the diseases is used to reduce the number of model compartments to achieve a unique solution. The reduced model is fitted simultaneously to inert gas retentions calculated from published V̇A/Q̇ distributions and normalized MBNWs obtained from similar subjects. Normal lungs and representative cases of emphysema and embolism are studied. Results. The normal, emphysematous and embolism models simplify to one, three and two alveolar compartments, respectively. Conclusions. The models reproduce their respective MIGET and MBNW patient results well, and predict disease-specific steady-state and dynamic soluble and insoluble gas responses.

KW - Modelling

KW - Ventilation inhomogeneity

KW - Ventilation/perfusion distribution

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SN - 0007-0912

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EP - 731

JO - British Journal of Anaesthesia

JF - British Journal of Anaesthesia

IS - 5

ER -

A tidally breathing model of ventilation, perfusion and volume in normal and diseased lungs

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Keywords

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