Effect of dual bronchodilation on the exercise capacity of individuals with non-cystic fibrosis bronchiectasis: A randomized controlled double-blind crossover study protocol (Preprint)

Bronchodilators (BDs) have been used therapeutically to improve exercise capacity in patients with other chronic respiratory diseases. However, the effect of BDs on the exercise capacity of individuals with non-cystic fibrosis bronchiectasis (NCFB) is poorly understood. To evaluate the effects of BDs on exercise capacity and thoracoabdominal kinematics in patients with NCFB. This crossover randomized controlled trial will involve 45 outpatients with NCFB aged 18 to 59 years. They will be evaluated in three visits. On Day 1, the maximal exercise capacity (cardiopulmonary exercise test) (Wpeak) will be assessed. On Day 2, individuals will be randomized to receive either BDs (ipratropium bromide 160 µg and fenoterol hydrobromide 400 µg) or a placebo and then undergo simultaneous endurance exercise capacity (constant work-rate exercise test) and thoracoabdominal kinematics (TK) (optoelectronic plethysmography) assessments. After a one-week washout (Day 3), the individuals will repeat the same assessments as on Day 2, in reverse order. The time to the limit of tolerance (Tlim) will be obtained in both groups (the BD and placebo groups) as the primary outcome. TK will be assessed at three time points: at rest, during unloaded exercise, and at 75%Wpeak. The total chest wall and compartmental volumes, as well as thoracoabdominal asynchrony, will be assessed. The assessors and patients will be blinded to the interventions (BDs or placebo). Data will be compared using t tests or Wilcoxon tests and repeated-measures ANOVA or Friedman tests. Categorical data will be analysed using the chi-square test or Fisher’s test. The associations among variables will be analysed using Pearson or Spearman correlation. The significance level will be set at 5% (P<.05). This is a study protocol and the research is ongoing. If successful, this study will demonstrate that the use of bronchodilators can improve exercise capacity and reduce thoracoabdominal asynchrony in adults with NCFB. Clinical Trials.gov PRS (Protocol Registration and Results System): NCT05183841.