Does dynamic hyperinflation contribute to dyspnoea during exercise in patients with COPD?

TitleDoes dynamic hyperinflation contribute to dyspnoea during exercise in patients with COPD?
Publication TypeJournal Article
Year of Publication2012
AuthorsGuenette, JA, Webb, KA, O'Donnell, DE
JournalEur Respir J
Date Published2012 Aug
KeywordsAdult, Aged, Body Mass Index, Case-Control Studies, Dyspnea, Exercise, Exercise Test, Exercise Tolerance, Female, Forced Expiratory Volume, Humans, Inspiratory Capacity, Male, Middle Aged, Pulmonary Disease, Chronic Obstructive, Respiration, Retrospective Studies, Time Factors

Dynamic hyperinflation (DH) during exercise occurs in most but not all patients with advanced chronic obstructive pulmonary disease (COPD). It is not known whether the presence or absence of DH has implications for dyspnoea and exercise tolerance. Therefore, we compared detailed ventilatory and sensory responses to exercise in hyperinflators and nonhyperinflators with moderate-to-severe COPD. Nonhyperinflators (n=65) were retrospectively identified from a sample of 427 patients and case-matched to a group of hyperinflators (n=65) based on sex, age, body mass index and % predicted forced expiratory volume in 1 s. Resting pulmonary function and constant work rate cycle exercise responses were compared. Hyperinflators decreased inspiratory capacity (IC) from rest to peak exercise by 0.46±0.24 L whereas the nonhyperinflators increased IC by 0.10±0.15 L (p<0.0001). There were no significant group differences in endurance time (9.11±5.98 versus 8.87±5.24 min) or dyspnoea intensity for any given time or ventilation. An inflection in tidal volume versus ventilation occurred in the majority of nonhyperinflators (n=61) and hyperinflators (n=62) at a similar time and ventilation. Mechanical constraints on tidal volume expansion and the attendant rise in dyspnoea intensity were similar in both groups. Dyspnoea intensity during exercise was associated with progressive mechanical constraints on tidal volume expansion regardless of the presence of DH.

Alternate JournalEur. Respir. J.
PubMed ID22183485