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

Abstract

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

Three-minute constant rate step test for detecting exertional dyspnea relief after bronchodilation in COPD

“…The stepping rates were selected based on the results of Perrault et al11,15 who reported on the development and test–retest reproducibility of the 3-MST performed at stepping rates of 18, 22, 26 and 32 steps/min in patients with GOLD stage 2–4 COPD. In Perrault et al’s study, <70% of the patients were able to complete all 3 minutes of exercise at both 26 and 32 steps/min, indicating that these stepping rates are likely too intense for routine clinical use in COPD 11.…”

“…Thus, lower stepping rates were used in the current study and we observed, as a result, consistently higher completion rates: 93%, 90%, 85% and 68% for 14, 16, 20 and 24 steps/min, respectively. The choice of Borg 0–10 scale to assess dyspnea was based on its wide use in COPD research and for consistency purpose with our research program on the use of the 3-minute walking and stepping tests 11,15. One interesting feature of the Borg scale is that we have a sense of how to interpret the magnitude of changes seen with treatment, a 1-point decrease in Borg dyspnea score being considered clinically relevant 24.…”

“…The sample size was thus estimated based on the previous work of our research group showing that 40 patients were sufficient to demonstrate the responsiveness of the 3-minute constant rate shuttle walking test to detect the improvement in exertional dyspnea following bronchodilation 15. Based on this past experience, we estimated that a similar number of patients should be enrolled in the current study.…”

“…By externally controlling the walking speed/stepping rate and limiting the duration of exercise to 3 minutes, these tests provoke a measureable and reproducible level of dyspnea (at a standardized and reproducible exercise stimulus) that may be encountered by patients with COPD during their activities of daily living12–14 and that may be amenable to therapy 11. To this end, a randomized, double-blind, placebo-controlled, crossover study from our group recently confirmed the responsiveness of the 3-minute constant rate shuttle walking test to detect statistically significant and clinically meaningful relief of exertional dyspnea after acute bronchodilation in patients with moderate-to-severe COPD 15. The aim of the current study was to assess the responsiveness of the 3-MST to detect the bronchodilator-induced relief of exertional dyspnea in COPD, testing the hypothesis that this exercise test is responsive to detect statistically significant and clinically meaningful relief of exertional dyspnea after acute bronchodilation in patients with moderate-to-severe COPD.…”

“…Drafting and editing of the manuscript for important intellectual content: BB, CAW-M, JB, HP, DJ and FM. AH, an employee of the sponsor, has been involved in the scientific development of this Investigator-Initiated Research Program 11,15. AH reviewed and commented on the manuscript with no obligation for the academic authors to incorporate any proposed changes.…”