Open AccessEffects of dynamic hyperinflation on exercise capacity and quality of life in stable COPD patients
Author(s) -
Zhao Li,
Peng Liyue,
Wu Baomei,
Bu Xiaoning,
Wang Chen
Publication year - 2016
Publication title -
the clinical respiratory journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.789
H-Index - 33
eISSN - 1752-699X
pISSN - 1752-6981
DOI - 10.1111/crj.12260
Subject(s) - dynamic hyperinflation , copd , medicine , lung volumes , hyperinflation , vo2 max , pulmonary function testing , cardiology , respiratory minute volume , ventilation (architecture) , respiratory system , physical therapy , lung , heart rate , monetary policy , mechanical engineering , blood pressure , monetary economics , economics , engineering
Background and Aims Dynamic hyperinflation ( DH ) is an important pathophysiological characteristic of chronic obstructive pulmonary disease ( COPD ). There is increasing evidence that DH has negative effects on exercise performance and quality of life. The objective of this study was to explore effects of DH on exercise capacity and quality of life in stable COPD patients. Methods Fifty‐eight COPD patients and 20 matched healthy individuals underwent pulmonary function test, 6‐min walk test and symptom‐limited cardiopulmonary exercise test ( CPET ). End‐expiratory lung volume/total lung capacity ratio ( EELV max/ TLC ) at peak exercise of CPET was evaluated, and EELV max/ TLC ≥ 75% was defined as ‘severe dynamic hyperinflation ( SDH )’. Results Of the 58 patients studied, 29 (50.0%) presented with SDH ( SDH + group, EELV max/ TLC 79.60 ± 3.60%), having worse maximal exercise capacity reflected by lower peakload, maximal oxygen uptake ( VO 2 max), maximal carbon dioxide output ( VCO 2 max) and maximal minute ventilation ( VE max) than did those without SDH ( SDH − group, EELV max/ TLC 67.44 ± 6.53%). The EELV max/ TLC ratio at peak exercise had no association with variables of pulmonary function and 6‐min walk distance (6 MWD ), but correlated inversely with peakload, VO 2 max, VCO 2 max and VE max (r = −0.300~−0.351, P < 0.05). Although no significant differences were observed, patients with EELV max/ TLC ≥ 75% tended to have higher COPD assessment test score (15.07 ± 6.55 vs 13.28 ± 6.59, P = 0.303). Conclusions DH develops variably during exercise and has a greater impact on maximal exercise capacity than 6 MWD , even in those with the same extent of pulmonary function impairment at rest.