Evaluation of a novel technique in airway clearance therapy – Specific Cough Technique (SCT) in cystic fibrosis: A pilot study of a series of N-of-1 randomised controlled trials

OBJECTIVES The aim of this pilot study was to evaluate the efficacy, safety and participants' perception of a novel technique in airway clearance therapy - specific cough technique in cystic fibrosis. METHODS We conducted randomised controlled individual trials (N-of-1 randomised controlled trials) in six adults. Each trial included 8 weeks of treatment with two interventions each week, one with specific cough technique and one with forced expiration technique. The efficacy was investigated by a blinded assessor measuring wet weight of sputum (g) after each session. Perceived usefulness and preference was self-reported at the end of study. Additional measurements included oxygen saturation and heart rate before and after each session and lung function (week 2). RESULTS Three of six participants produced significantly higher mean sputum weight when using specific cough technique, differences being 21%, 38% and 23%, respectively. In three of the six participants, mean sputum weight was lower after forced expiration technique than after specific cough technique in each of the eight treatment pairs. Participant-reported outcomes were completed in all participants. Specific cough technique was reported to be easier to use in daily treatments and more normalising in everyday life. CONCLUSION Specific cough technique was well tolerated and accepted by the participants with cystic fibrosis. Specific cough technique was non-inferior to forced expiration technique in terms of sputum production, thus specific cough technique appears to represent a promising alternative for clearing sputum in airway clearance therapy.