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

Abstract

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.