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).

Inclusion Criteria: * 1\. Diagnosed with COPD by a pulmonologist, with spirometry confirming post-bronchodilator FEV₁/FVC \< 70% within the past 12 months 2. Aged between 40 and 90 years, receiving regular follow-up at the pulmonology outpatient clinic 3. Able to communicate and follow instructions in Mandarin or Taiwanese 4. Willing to participate and comply with home-based pulmonary rehabilitation intervention Exclusion Criteria: * 1\. Active pulmonary tuberculosis, pneumothorax, or malignant respiratory disease 2. Severe cognitive impairment, intellectual disability, or communication disorder preventing instruction comprehension or intervention compliance 3. Currently in acute exacerbation of COPD, or primary diagnosis of bronchial asthma 4. GOLD Stage I COPD (mild, post-bronchodilator FEV₁ ≥ 80% predicted)