Detecting improvements in dyspnea in COPD using a three-minute constant rate shuttle walking protocol

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.

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.

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.

This 3-minute shuttle walking protocol adequately detected dyspnea and breathing pattern improvements following acute bronchodilation in COPD.