Comparison of the active cycle breathing technique with other self-administered breathing techniques for the management of mucociliary production in cystic fibrosis: A systematic review.

BACKGROUND: Cystic fibrosis (CF) is characterized by excessive airway mucus, recurrent infections, impaired ventilation, and progressive decline in lung function. Airway clearance techniques are central to management. Among them is the active cycle of breathing technique (ACBT), which incorporates breathing control, thoracic expansion exercises, and the forced expiratory technique (FET). Comparative evaluation with other self-administered exercises is needed to identify the most effective approach for clinical use. OBJECTIVES: To evaluate the effects of ACBT compared with other self-administered or non-device airway clearance techniques on pulmonary function in individuals with CF. METHODS: A systematic search of PubMed, MEDLINE, and the Cochrane Library was conducted according to PRISMA guidelines. Randomized controlled and crossover trials comparing ACBT with other self-administered or home-based airway clearance techniques were included. Risk of bias was assessed using the Cochrane tool. Study selection was performed by one reviewer and verified by a second reviewer. Due to methodological and clinical heterogeneity, findings were synthesized narratively without meta-analysis. RESULTS: Ten studies met the inclusion criteria. Eight reported pulmonary function outcomes; three found significant short-term improvements in ACBT over postural drainage (p < 0.01), autogenic drainage (p < 0.002), and assisted ACBT (p < 0.07). Seven studies measured sputum weight, with four showing significant reductions (p < 0.05-0.001). One study found higher oxygen saturation after ACBT versus postural drainage (p < 0.05). Six studies using the Leicester Cough Questionnaire reported improved physical and psychological well-being. Limited evidence suggested short-term improvements in oxygen saturation and quality of life. Most included studies were small, heterogeneous, and conducted before the widespread use of cystic fibrosis transmembrane conductance regulator modulator therapies. CONCLUSION: ACBT may provide short-term benefits in pulmonary function, sputum clearance, and quality of life in people with CF. However, evidence remains limited by small sample sizes, methodological heterogeneity, and the predominance of older studies. Further high-quality randomized controlled trials are needed to establish the long-term effectiveness and contemporary relevance of ACBT.