HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Free Full Text (PDF) Free All Versions of this Article: 105/3/832    most recent 01307.2007v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Scichilone, N. Articles by Bellia, V. Search for Related Content PubMed PubMed Citation Articles by Scichilone, N. Articles by Bellia, V.

The airway response to deep inspirations decreases with COPD severity and is associated with airway distensibility assessed by computed tomography

¹Dipartimento di Medicina, Pneumologia, Fisiologia e Nutrizione Umana, Sezione di Pneumologia e Medicina, and ²Dipartimento di Biotecnologie e Medicina Legale, Sezione di Scienze Radiologiche, University of Palermo, Palermo, Italy; ³Department of Environmental Health Sciences, Johns Hopkins University, Baltimore, Maryland; and ⁴National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland

Submitted 11 December 2007 ; accepted in final form 7 July 2008

In patients with mild chronic obstructive pulmonary disease (COPD), the effect of deep inspirations (DIs) to reverse methacholine-induced bronchoconstriction is largely attenuated. In this study, we tested the hypothesis that the effectiveness of DI is reduced with increasing disease severity and that this is associated with a reduction in the ability of DI to distend the airways. Fifteen subjects [Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage I–II: n = 7; GOLD stage III–IV: n = 8] underwent methacholine bronchoprovocation in the absence of DI, followed by DI. The effectiveness of DI was assessed by their ability to improve inspiratory vital capacity and forced expiratory volume in 1 s (FEV₁). To evaluate airway distensibility, two sets of high-resolution computed tomography scans [at residual volume (RV) and at total lung capacity] were obtained before the challenge. In addition, mean parenchymal density was calculated on the high-resolution computed tomography scans. We found a strong correlation between the response to DI and baseline FEV₁ %predicted (r² = 0.70, P < 0.0001) or baseline FEV₁/forced vital capacity (r² = 0.57, P = 0.001). RV %predicted and functional residual capacity %predicted correlated inversely (r² = 0.33, P = 0.02 and r² = 0.32, P = 0.03, respectively), and parenchymal density at RV correlated directly (r² = 0.30, P = 0.03), with the response to DI. Finally, the effect of DI correlated to the change in large airway area from RV to total lung capacity (r² = 0.44, P = 0.01). We conclude that loss of the effects of DI is strongly associated with COPD severity and speculate that the reduction in the effectiveness of DI is due to the failure to expand the lungs because of the hyperinflated state and/or the parenchymal damage that prevents distension of the airways with lung inflation.

high-resolution computed tomography; methacholine; airway-parenchyma interdependence; bronchoprovocation; hyperinflation