The effectiveness of the active cycle of breathing technique in patients with chronic respiratory diseases: A systematic review

Active cycle breathing technique (ACBT), which includes cycle of breathing control, thoracic expansion exercises and forced expiratory technique (FET), appears to have beneficial effects in patients with a variety of respiratory diseases. This systematic review provides an update on the new related studies, expanding the evidence base through the last 12 years and specifically evaluating the effectiveness of ACBT on pulmonary function-related outcome variables in patients with chronic respiratory diseases.MEDLINE/Pubmed, PEDro, and Cochrane Library for Randomized Controlled Trials were searched between September 2008 and December 2021, in continuance of a previous systematic review, to identify randomized clinical trials and/or crossover studies comparing ACBT to other respiratory treatment techniques in patients with chronic obstructive pulmonary diseases, cystic fibrosis, or bronchiectasis.Eleven studies were included and the quality of most of them was moderate to good. The outcomes most frequently assessed were forced expiratory volume in 1 s (FEV1), sputum wet weight, forced vital capacity (FVC), and peak expiratory flow rate. Secondary outcomes were quality of life and dyspnea. Various comparators were identified and most of them assessed the ACBT as an effective method in comparison with other respiratory treatment modalities. Most studies revealed that ACBT/FET had at least an equally beneficial short-term effect on sputum wet weight, FEV1 and FVC compared to other treatment methods.The results of this updating review reinforced the data of a previous systematic review regarding the beneficial impact of ACBT for the short-term improvement in respiratory tract secretions clearance and pulmonary function. ACBT is effective in increasing the expectorated sputum volume, in reducing viscoelasticity of the secretion and in relieving symptoms such as dyspnea.