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

Chronic Obstructive Pulmonary Disease (COPD) is a progressive and irreversible airway obstruction disease. Patients frequently experience dyspnea, sputum retention, repeated exacerbations, reduced exercise tolerance, poor sleep quality, and depressive symptoms. Traditional pulmonary rehabilitation is largely hospital-based and limited by patient age, comorbidities, transportation barriers, and healthcare resource constraints. Active Cycle of Breathing Technique (ACBT) is a non-invasive, low-cost structured breathing method comprising three phases: breathing control, thoracic expansion exercises, and forced expiration technique. Oscillatory Positive Expiratory Pressure (O-PEP) uses a tube valve device to generate oscillatory airflow and positive pressure during expiration, facilitating airway secretion mobilization and clearance. This study adopts a block-randomized crossover design. Group A receives ACBT combined with O-PEP during Weeks 1-8, then standard care during Weeks 9-16. Group B receives standard care during Weeks 1-8, then ACBT combined with O-PEP during Weeks 9-16. Intervention consists of 3 ACBT cycles followed by 10-15 O-PEP expirations, twice daily (at least 8 hours apart), for 8 weeks. All participants receive one-on-one standardized training prior to intervention, with weekly remote follow-up. The O-PEP device will be collected from Group A after Week 8 to prevent carryover. Standard care includes disease education, smoking cessation, self-management skills, and conventional breathing exercises. Data analysis will use Generalized Estimating Equations (GEE) following Intention-to-Treat (ITT) principles.

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)