Journal article
Relating indices of inert gas washout to localised bronchoconstriction
Respiratory physiology & neurobiology, Vol.183(3), pp.224-233
09/30/2012
DOI: 10.1016/j.resp.2012.06.031
PMCID: PMC3505678
PMID: 22771781
Abstract
► We model nitrogen washout in anatomically-representative airway and tissue model. ► Ventilation is driven by a nominal pleural pressure change. ► Ventilation defects seen on imaging are simulated by narrowing airway geometry. ► Multiple breath washout is simulated for the integrated system. ► Estimates of asthma severity may differ between using imaging or multiple breath washout.
Asthma is typically characterised by increased ventilation heterogeneity. This can be directly inferred from the visualisation of ventilation defects in imaging studies, or indirectly inferred from indices derived from the multiple-breath nitrogen washout (MBNW). The basis for the understanding of the MBNW indices and their implication for changes in structure and function at the largest and smallest scales in the lung has been facilitated by mathematical models for inert gas transport. A new model is presented that couples airway resistance and regional tissue compliance, for simulation of the effect of ‘patchy’ bronchoconstriction – as inferred from imaging studies – on the Scond index of ventilation heterogeneity. Patches of reduced washin gas concentration can emerge by constricting only the terminal bronchioles within localised regions, however this pattern of constriction is insufficient to affect Scond; Scond from this model is only sensitive to constriction that occurs within entire contiguous regions. Furthermore the model illustrates the possibility that the MBNW may not detect gas trapped in ventilation defects.
Details
- Title: Subtitle
- Relating indices of inert gas washout to localised bronchoconstriction
- Creators
- Jennine H Mitchell - Auckland Bioengineering Institute, University of Auckland, Auckland, New ZealandEric A Hoffman - Departments of Radiology, Bioengineering, and Medicine, University of Iowa, Iowa City, IA, USAMerryn H Tawhai - Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
- Resource Type
- Journal article
- Publication Details
- Respiratory physiology & neurobiology, Vol.183(3), pp.224-233
- DOI
- 10.1016/j.resp.2012.06.031
- PMID
- 22771781
- PMCID
- PMC3505678
- NLM abbreviation
- Respir Physiol Neurobiol
- ISSN
- 1569-9048
- eISSN
- 1878-1519
- Publisher
- Elsevier B.V
- Language
- English
- Date published
- 09/30/2012
- Academic Unit
- Roy J. Carver Department of Biomedical Engineering; Radiology; Internal Medicine
- Record Identifier
- 9984051554302771
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