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

• Published in: Journal of applied physiology (1985) Vol. 105; no. 3; pp. 832 - 838
• Main Authors: Scichilone, Nicola, La Sala, Alba, Bellia, Maria, Fallano, Katherine, Togias, Alkis, Brown, Robert H, Midiri, Massimo, Bellia, Vincenzo
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Am Physiological Soc 01.09.2008; American Physiological Society
• Subjects: Administration, Inhalation; Aged; Aged, 80 and over; Airway management; Biological and medical sciences; Bronchial Hyperreactivity - pathology; Bronchial Hyperreactivity - physiopathology; Bronchial Provocation Tests; Bronchoconstrictor Agents - administration & dosage; Chronic obstructive pulmonary disease; Computed tomography; Correlation analysis; Elasticity; Forced Expiratory Volume; Fundamental and applied biological sciences. Psychology; Gold; Humans; Inhalation; Lungs; Methacholine Chloride - administration & dosage; Middle Aged; Pulmonary Disease, Chronic Obstructive - diagnostic imaging; Pulmonary Disease, Chronic Obstructive - physiopathology; Respiratory System - diagnostic imaging; Respiratory System - physiopathology; Severity of Illness Index; Spirometry; Studies; Tomography; Tomography, Spiral Computed; Vital Capacity; Lung disease; Inspiration; High resolution; Hyperinflation; Respiratory disease; high-resolution computed tomography; Parenchyma; bronchoprovocation; Respiratory system; Respiratory tract; Vertebrata; Mammalia; Decrease; airway-parenchyma interdependence; Tomography; Bronchus disease; Chronic obstructive pulmonary disease; Respiration; methacholine
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.01307.2007

1 Dipartimento di Medicina, Pneumologia, Fisiologia e Nutrizione Umana, Sezione di Pneumologia e Medicina, and 2 Dipartimento di Biotecnologie e Medicina Legale, Sezione di Scienze Radiologiche, University of Palermo, Palermo, Italy; 3 Department of Environmental Health Sciences, Johns Hopkins University, Baltimore, Maryland; and 4 National 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 (FEV 1 ). 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 FEV 1 %predicted ( r 2 = 0.70, P < 0.0001) or baseline FEV 1 /forced vital capacity ( r 2 = 0.57, P = 0.001). RV %predicted and functional residual capacity %predicted correlated inversely ( r 2 = 0.33, P = 0.02 and r 2 = 0.32, P = 0.03, respectively), and parenchymal density at RV correlated directly ( r 2 = 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 ( r 2 = 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 Address for reprint requests and other correspondence: N. Scichilone, Dipartimento di Medicina, Pneumologia, Fisiologia e Nutrizione Umana, Univ. of Palermo, via Trabucco 180, 90146 Palermo, Italy (e-mail: n.scichilone{at}libero.it )