Can bronchodilators improve exercise tolerance in COPD patients without dynamic hyperinflation?

Objective: To investigate the modulatory effects that dynamic hyperinflation (UFO, defined as a reduction in inspiratory capacity (lC), has on exercise tolerance after bronchodilator in patients with COPD. Methods: An experimental, randomized study involving 30 COPD patients without severe hypoxemia. At baseline, the patients underwent clinical assessment, spirometry, and incremental cardiopulmonary exercise testing (CPET). On two subsequent visits, the patients were randomized to receive a combination of inhaled fenoterol/ipratropium or placebo. All patients then underwent spirometiy and submaximal CPET at constant speed up to the limit of tolerance (Tlim). The patients who showed Delta lC(peak-rest) 0.05). in addition, both groups showed similar improvements in Tlim after bronchodilator (median [interquartile range]: 22% [3-60% vs. 10% [3-53%]; p > 0.05). Conclusions: Improvement in TLim was associated with an increase in lC at rest after bronchodilator in HD- patients with COPD. However, even without that improvement, COPD patients can present with greater exercise tolerance after bronchodilator provided that they develop DH during exercise.Fac Ciencias Med Paraiba, Joao Pessoa, Paraiba, BrazilUniv Fed Rio Grande do Sul, Fac Med, Porto Alegre, RS, BrazilFac Med ABC, Disciplina Pneumol, Santo Andre, SP, BrazilFac Med ABC, Disciplina Pneumol, Setor Reabilitacao Pulmonar, Santo Andre, SP, BrazilQueens Univ, Div Resp & Crit Care Med, Kingston, ON, CanadaKingston Gen Hosp, Kingston, ON, CanadaUniv Fed Sao Paulo, Sao Paulo, BrazilUniv Fed Sao Paulo, Sao Paulo, BrazilWeb of Scienc