Respiratory system impedance with impulse oscillometry in healthy and COPD subjects: ECLIPSE baseline results
Courtney Crim, Bartolome Celli, Lisa D Edwards, Emiel Wouters, Harvey O Coxson, Ruth Tal-Singer, Peter M A Calverley, ECLIPSE investigators, Y Ivanov, K Kostov, J Bourbeau, M Fitzgerald, P Herna, K Killian, R Levy, F Maltais, D O'Donnell, J Krepelka, J Vestbo, E Wouters, D Quinn, P Bakke, M Kosnik, A Agusti, Jaume Sauleda, Y Feschenko, V Gavrisyuk, L Yashina, W MacNee, D Singh, J Wedzicha, A Anzueto, S Braman, R Casaburi, B Celli, G Giessel, M Gotfried, N Hanania, D Mahler, B Make, S Rennard, C Rochester, P Scanlon, D Schuller, F Sciurba, A Sharafkhaneh, T Siler, E Silverman, A Wanner, R Wise, R ZuWallac, H Coxson, C Crim, L Edwards, D Lomas, W MacNee, E Silverman, R Tal- Singer, J Vestbo, J Yates, A Agusti, P Bakke, P Calverley, B Celli, C Crim, B Miller, W MacNee, S Rennard, R Tal-Singer, E Wouters, Courtney Crim, Bartolome Celli, Lisa D Edwards, Emiel Wouters, Harvey O Coxson, Ruth Tal-Singer, Peter M A Calverley, ECLIPSE investigators, Y Ivanov, K Kostov, J Bourbeau, M Fitzgerald, P Herna, K Killian, R Levy, F Maltais, D O'Donnell, J Krepelka, J Vestbo, E Wouters, D Quinn, P Bakke, M Kosnik, A Agusti, Jaume Sauleda, Y Feschenko, V Gavrisyuk, L Yashina, W MacNee, D Singh, J Wedzicha, A Anzueto, S Braman, R Casaburi, B Celli, G Giessel, M Gotfried, N Hanania, D Mahler, B Make, S Rennard, C Rochester, P Scanlon, D Schuller, F Sciurba, A Sharafkhaneh, T Siler, E Silverman, A Wanner, R Wise, R ZuWallac, H Coxson, C Crim, L Edwards, D Lomas, W MacNee, E Silverman, R Tal- Singer, J Vestbo, J Yates, A Agusti, P Bakke, P Calverley, B Celli, C Crim, B Miller, W MacNee, S Rennard, R Tal-Singer, E Wouters
Abstract
Rationale: Current assessment of COPD relies extensively on the use of spirometry, an effort-dependent maneuver. Impulse oscillometry (IOS) is a non-volitional way to measure respiratory system mechanics, but its relationship to structural and functional measurements in large groups of patients with COPD is not clear.
Objectives: We evaluated the ability of IOS to detect and stage COPD severity in the prospective ECLIPSE cohort of COPD patients defined spirometrically, and contrasted with smoking and non-smoking healthy subjects. Additionally, we assessed whether IOS relates to extent of CT-defined emphysema.
Methods: We measured lung impedance with IOS in healthy non-smokers (n = 233), healthy former smokers (n = 322) or patients with COPD (n = 2054) and related these parameters with spirometry and areas of low attenuation in lung CT.
Measurements and main results: In healthy control subjects, IOS demonstrated good repeatability over 3 months. In the COPD group, respiratory system impedance was worse compared with controls as was frequency dependence of resistance, which related to GOLD stage. However, 29-86% of the COPD subjects had values that fell within the 90% confidence interval of several parameters of the healthy non-smokers. Although mean values for impedance parameters and CT indices worsened as GOLD severity increased, actual correlations between them were poor (r ≤ 0.16).
Conclusions: IOS can be reliably used in large cohorts of subjects to assess respiratory system impedance. Cross-sectional data suggest that it may have limited usefulness in evaluating the degree of pathologic disease, whereas its role in assessing disease progression in COPD currently remains undefined.
Trial registration: ClinicalTrials.gov NCT00292552.
Copyright © 2011. Published by Elsevier Ltd.
Source: PubMed