Elsevier

Respiratory Medicine

Volume 106, Issue 12, December 2012, Pages 1695-1705
Respiratory Medicine

Walking exercise response to bronchodilation in mild COPD: A randomized trial

https://doi.org/10.1016/j.rmed.2012.08.021Get rights and content
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Summary

Rationale

Patients with mild chronic obstructive pulmonary disease (COPD) present abnormal ventilatory mechanics during exercise and may require bronchodilator therapy. However, bronchodilation does not enhance cycling exercise tolerance in these patients whereas walking may be more sensitive to the effects of bronchodilation.

Objectives

To characterize the impact of bronchodilation on i) exercise tolerance ii) cardiopulmonary response and iii) dynamic hyperinflation following an endurance shuttle walking test in patients with mild COPD.

Methods

In a randomized double-blind cross-over trial, 37 patients with GOLD stage I COPD (FEV1, 96 ± 2% predicted, mean ± SEM) completed an endurance shuttle walking test up to exhaustion 90 ± 15 min following nebulization of a placebo [NaCl] or of ipratropium bromide/salbutamol sulfate (500 μg/2.5 mg) combination.

Results

FEV1 significantly increased following bronchodilation compared with placebo (0.17 ± 0.02 vs. −0.02 ± 0.01 L, p < 0.0001, mean ± SEM). The difference in walking endurance time between bronchodilation and placebo was not statistically significant (Δ15 ± 12 s, p = 0.21), with the upper and lower boundaries of the 95% confidence interval [−9–40 s, 95% CI] within the proposed minimally important difference for this variable (65 s). The ratio of breathing frequency to tidal volume tended to be decreased with bronchodilation during exercise (p = 0.07), indicating a deeper and slower breathing pattern with bronchodilation. Bronchodilation had a significant effect on dynamic hyperinflation at isotime and at peak exercise.

Conclusion

Bronchodilation did not improve walking endurance in patients with mild COPD despite small physiological benefits of uncertain clinical relevance.

Keywords

Bronchodilators
Chronic obstructive pulmonary disease
GOLD I
Exercise tolerance
Walking

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