Effectiveness of Active Cycle of Breathing Techniques in Patients With Chronic Obstructive Pulmonary Disease: A Randomized Controlled Trial

This study aims to examine the effects of Active Cycle of Breathing Technique (ACBT) on pulmonary function, sleep quality, depressive symptoms, and dyspnea in patients with Chronic Obstructive Pulmonary Disease. A block-randomized crossover trial will be conducted at the pulmonology outpatient clinic of a regional teaching hospital in eastern Taiwan. Participants aged 40-90 years with physician-diagnosed COPD (post-bronchodilator FEV₁/FVC \< 70%) will be randomly allocated into two groups. The total observation period is 16 weeks with 5 data collection time points: T0 (baseline), T1 (Week 4), T2 (Week 8), T3 (Week 12), and T4 (Week 16). Each intervention period lasts 8 weeks. Primary outcomes are dyspnea (mMRC) and COPD symptom burden (CAT). Secondary outcomes include pulmonary function (FEV₁, FVC), sleep quality (PSQI), and depressive symptoms (DASS-21).