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Deep inspirations protect against airway closure in nonasthmatic subjects.
J Appl Physiol (1985). 2009 Aug; 107(2):564-9.JA

Abstract

The mechanism by which deep inspirations protect against increased airway responsiveness in nonasthmatic subjects is not known. The aim was to investigate the role of airway closure and airway narrowing in deep inspiration bronchoprotection. Twelve nonasthmatic and nine asthmatic subjects avoided deep inspirations (DI) for 20 min, then took five DI expired to functional residual capaciy (DI-FRC) or, on a separate day, no DI (no DI) before inhaling a single dose of methacholine. On another day, eight nonasthmatic subjects took five DI expired to residual volume (DI-RV). Peripheral airway function was measured by respiratory system reactance (Xrs), using the forced oscillation technique, and by forced vital capacity (FVC) as an index of airway closure. Respiratory system resistance (Rrs) and forced expiratory volume in 1 s (FEV1)/FVC were measured as indexes of airway narrowing. In nonasthmatic subjects, DI-FRC reduced the response measured by FEV1 (P=0.019), Xrs (P=0.02), and FVC (P=0.0005) but not by Rrs (P=0.15) or FEV1/FVC (P=0.52) compared with no DI. DI-RV had a less protective effect than DI-FRC on response measured by FEV1 (P=0.04) and FVC (P=0.016). There was no difference between all protocols when the response was measured by Xrs (P=0.20), Rrs (P=0.88), or FEV1/FVC (P=0.88). DI had no effect on methacholine response in asthmatic subjects. DI protect against airway responsiveness through an effect on peripheral airways involving reduced airway closure. The protective effect of DI on FEV1 and FVC was abolished by expiration to residual volume. We speculate that the reduced airway closure is due to reduced baseline ventilation heterogeneity and/or reduced airway surface tension.

Authors+Show Affiliations

Woolcock Institute of Medical Research, Cooperative REsearch Centre for Asthma, University of Sydney, P.O. Box M77 Missenden Rd, Sydney, NSW 2050, Australia. dcha7069@woolcock.org.auNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

19443748

Citation

Chapman, David G., et al. "Deep Inspirations Protect Against Airway Closure in Nonasthmatic Subjects." Journal of Applied Physiology (Bethesda, Md. : 1985), vol. 107, no. 2, 2009, pp. 564-9.
Chapman DG, Berend N, King GG, et al. Deep inspirations protect against airway closure in nonasthmatic subjects. J Appl Physiol. 2009;107(2):564-9.
Chapman, D. G., Berend, N., King, G. G., McParland, B. E., & Salome, C. M. (2009). Deep inspirations protect against airway closure in nonasthmatic subjects. Journal of Applied Physiology (Bethesda, Md. : 1985), 107(2), 564-9. https://doi.org/10.1152/japplphysiol.00202.2009
Chapman DG, et al. Deep Inspirations Protect Against Airway Closure in Nonasthmatic Subjects. J Appl Physiol. 2009;107(2):564-9. PubMed PMID: 19443748.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Deep inspirations protect against airway closure in nonasthmatic subjects. AU - Chapman,David G, AU - Berend,Norbert, AU - King,Gregory G, AU - McParland,Brent E, AU - Salome,Cheryl M, Y1 - 2009/05/14/ PY - 2009/5/16/entrez PY - 2009/5/16/pubmed PY - 2009/9/18/medline SP - 564 EP - 9 JF - Journal of applied physiology (Bethesda, Md. : 1985) JO - J. Appl. Physiol. VL - 107 IS - 2 N2 - The mechanism by which deep inspirations protect against increased airway responsiveness in nonasthmatic subjects is not known. The aim was to investigate the role of airway closure and airway narrowing in deep inspiration bronchoprotection. Twelve nonasthmatic and nine asthmatic subjects avoided deep inspirations (DI) for 20 min, then took five DI expired to functional residual capaciy (DI-FRC) or, on a separate day, no DI (no DI) before inhaling a single dose of methacholine. On another day, eight nonasthmatic subjects took five DI expired to residual volume (DI-RV). Peripheral airway function was measured by respiratory system reactance (Xrs), using the forced oscillation technique, and by forced vital capacity (FVC) as an index of airway closure. Respiratory system resistance (Rrs) and forced expiratory volume in 1 s (FEV1)/FVC were measured as indexes of airway narrowing. In nonasthmatic subjects, DI-FRC reduced the response measured by FEV1 (P=0.019), Xrs (P=0.02), and FVC (P=0.0005) but not by Rrs (P=0.15) or FEV1/FVC (P=0.52) compared with no DI. DI-RV had a less protective effect than DI-FRC on response measured by FEV1 (P=0.04) and FVC (P=0.016). There was no difference between all protocols when the response was measured by Xrs (P=0.20), Rrs (P=0.88), or FEV1/FVC (P=0.88). DI had no effect on methacholine response in asthmatic subjects. DI protect against airway responsiveness through an effect on peripheral airways involving reduced airway closure. The protective effect of DI on FEV1 and FVC was abolished by expiration to residual volume. We speculate that the reduced airway closure is due to reduced baseline ventilation heterogeneity and/or reduced airway surface tension. SN - 8750-7587 UR - https://www.unboundmedicine.com/medline/citation/19443748/Deep_inspirations_protect_against_airway_closure_in_nonasthmatic_subjects_ L2 - http://www.physiology.org/doi/full/10.1152/japplphysiol.00202.2009?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -