Active Cycle of Breathing Technique Versus High-Frequency Chest Wall Oscillation in Pulmonary Function in Adult Chronic Obstructive Pulmonary Disease Patients: A Randomized Clinical Trial

Abstract

Background: Chronic obstructive pulmonary disease (COPD) is a progressive, irreversible airflow limitation disorder representing a leading global cause of morbidity and mortality, for which physiotherapy-based airway clearance constitutes a critical management component. Objective: To compare the effects of the active cycle of breathing technique (ACBT) and high-frequency chest wall oscillation (HFCWO) on pulmonary function, exercise capacity, dyspnea severity, and composite BODE index scores in adult patients with stage 3–4 COPD. Methods: A parallel-group randomized clinical trial was conducted at the Pulmonary Department of DHQ Hospital Narowal over six months. Forty-two participants meeting GOLD stage 3–4 criteria were consecutively recruited and randomly allocated to ACBT with routine chest physiotherapy (Group A; n = 21) or HFCWO via pneumatic vest system (Group B; n = 21). Both groups received three sessions per week over four weeks (12 total sessions). Outcome measures included FEV₁ % predicted, six-minute walk distance (6MWD), mMRC dyspnea score, BMI, and composite BODE index, assessed at baseline and week four. Within-group comparisons used paired-samples t-tests and between-group comparisons used independent-samples t-tests (SPSS v25; α = 0.05). Results: HFCWO produced a significantly greater improvement in FEV₁ % predicted compared with ACBT (67.79 ± 12.73% vs 53.89 ± 9.30%; mean difference: 13.90 percentage points; Cohen's d = 1.25; p < 0.001) and in 6MWD (409.47 ± 108.25 m vs 346.47 ± 45.01 m; d = 0.76; p = 0.025). Both groups achieved significant within-group BODE index improvements (ACBT: Δ = +2.32, p = 0.048; HFCWO: Δ = +2.41, p = 0.050). No significant between-group difference was observed for mMRC dyspnea score (p = 0.247) or BMI (p = 0.124). Conclusion: Both ACBT and HFCWO significantly improve functional outcomes in stage 3–4 COPD; however, HFCWO demonstrates superior efficacy in spirometric and exercise capacity domains, supporting its preferential use in advanced obstructive disease where effort-dependent techniques are limited by disease severity.