Journal article
Effects of airway tree asymmetry on the emergence and spatial persistence of ventilation defects
Journal of applied physiology (1985), Vol.117(4), pp.353-362
08/15/2014
DOI: 10.1152/japplphysiol.00881.2013
PMID: 24947031
Abstract
Asymmetry and documented, but their effects on bronchoconstriction and ventilation distribution in asthma are unclear. In a series of seminal studies, Venegas et al. have shown that bronchoconstriction may lead to self-organized patterns of patchy ventilation in a computational model that could explain areas of poor ventilation [ventilation defects (VDefs)] observed in positron emission tomography images during induced bronchoconstriction. To investigate effects of anatomic asymmetry on the emergence of VDefs we used the symmetric tree computational model that Venegas and Winkler developed using different trees, including an anatomic human airway tree provided by M. Tawhai (University of Auckland), a symmetric tree, and three trees with intermediate asymmetry (Venegas JG, Winkler T, Musch G, Vidal Melo MF, Layfield D, Tgavalekos N, Fischman AJ, Callahan RJ, Bellani G, Harris RS. Nature 434: 777-782, 2005 and Winkler T, Venegas JG. J Appl Physiol 103: 655-663, 2007). Ventilation patterns, lung resistance (R-L), lung elastance (E-L), and the entropy of the ventilation distribution were compared at different levels of airway smooth muscle activation. We found VDefs emerging in both symmetric and asymmetric trees, but VDef locations were largely persistent in asymmetric trees, and bronchoconstriction reached steady state sooner than in a symmetric tree. Interestingly, bronchoconstriction in the asymmetric tree resulted in lower R-L (similar to%50) and greater E-L (similar to%25). We found that VDefs were universally caused by airway instability, but asymmetry in airway branching led to local triggers for the self-organized patchiness in ventilation and resulted in persistent locations of VDefs. These findings help to explain the emergence and the persistence in location of VDefs found in imaging studies.
Details
- Title: Subtitle
- Effects of airway tree asymmetry on the emergence and spatial persistence of ventilation defects
- Creators
- D. Leary - Dalhousie UniversityT. Winkler - Harvard UniversityA. Braune - Massachusetts General HospitalG. N. Maksym - Dalhousie University
- Resource Type
- Journal article
- Publication Details
- Journal of applied physiology (1985), Vol.117(4), pp.353-362
- DOI
- 10.1152/japplphysiol.00881.2013
- PMID
- 24947031
- NLM abbreviation
- J Appl Physiol (1985)
- ISSN
- 8750-7587
- eISSN
- 1522-1601
- Publisher
- Amer Physiological Soc
- Number of pages
- 10
- Grant note
- R01HL087281 / National Heart, Lung, and Blood Institute; United States Department of Health & Human Services; National Institutes of Health (NIH) - USA; NIH National Heart Lung & Blood Institute (NHLBI) Atlantic Canada Opportunities Agency Canadian Thoracic Society studentship Natural Sciences and Engineering Research Council of Canada Strategic Operating Grant; Natural Sciences and Engineering Research Council of Canada (NSERC)
- Language
- English
- Date published
- 08/15/2014
- Academic Unit
- Anesthesia
- Record Identifier
- 9985141862602771
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