Detecting Improvements in Dyspnea in COPD Using a Three-Minute Constant Rate Shuttle Walking Protocol

Abstract

Rationale: We examined the responsiveness of a 3-minute constant rate shuttle walking protocol to detect improvements in exertional dyspnea following acute bronchodilation in COPD. Our hypothesis was that the 3-minute constant rate shuttle walking protocol would be able to adequately put forth improvements in exertional dyspnea following acute bronchodilation in this population. Methods: Using a placebo controlled, double-blind cross-over design, 39 patients with moderate to severe COPD performed a 3-min constant rate shuttle walking test during which they were asked to walk on a flat corridor at a speed that was externally imposed by an audio signal. During the test, dyspnea was graded using the 10-point modified Borg scale. The test was performed twice, following the administration of saline placebo or of 500 μg nebulized ipratropium bromide. Results: Improvements of respiratory pattern (respiratory rate and tidal volume) and statistically and clinically significant reductions in Borg dyspnea scores (? dyspnea score = 1.0 ± 0.2, p < 0.01) were seen during the 3-min shuttle walking protocol with ipratropium bromide compared to placebo. Conclusion: This 3-minute shuttle walking protocol adequately detected dyspnea and breathing pattern improvements following acute bronchodilation in COPD.