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Chronic bronchitis leads to accelerated hyperinflation in COPD patients during exercise
Author(s) -
Zhang Wen,
Lu Haitao,
Peng Liyue,
Ren Xiaoxia,
Lu Yong,
An Li,
Zhang Hong,
Tan Xiaoyue,
Sun Xingguo,
Huang Kewu
Publication year - 2015
Publication title -
respirology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 85
eISSN - 1440-1843
pISSN - 1323-7799
DOI - 10.1111/resp.12504
Subject(s) - medicine , copd , hyperinflation , chronic bronchitis , dynamic hyperinflation , physical therapy , pulmonary disease , bronchitis , exertional dyspnea , intensive care medicine , cardiology , lung , lung volumes , monetary policy , monetary economics , economics
Background and objective It is not known whether patients with chronic obstructive pulmonary disease ( COPD ) have a different exercise capacity with ( CB + ) or without accompanying chronic bronchitis ( CB − ). Methods We conducted spirometry, a 6‐min walk distance test and cardiopulmonary exercise test in 50 age‐matched healthy control subjects, 45 COPD patients without CB ( CB − ) and 37 COPD patients with CB ( CB + ). A multiple regression model was established to identify factors independently associated with peak oxygen consumption (V ˙O 2). Results Patients with and without CB had similar forced expiratory volume in 1 s ( FEV 1 ). CB + patients had a lowerV ˙O 2. CB + and CB − participants had similar increases in tidal volume at peak exercise; however, CB + patients had an increased respiratory rate ( RR ). These patients reached the peak value for ratio of end‐expiratory lung volume to total lung capacity ( TLC ) at a lower work load. A stepwise multiple linear regression analysis identified chronic bronchitis, FEV 1 , diffusing capacity for carbon monoxide, the ratio of residual volume to TLC and serum tumour necrosis factor‐α as independent predictors of peakV ˙O 2. Conclusions CB significantly lowers exercise capacity in COPD patients because of dynamic hyperinflation during exercise. The accelerated dynamic hyperinflation may contribute to increased airway and systemic inflammation in COPD patients.