Evaluation of a novel sputum clearance technique--hydro-acoustic therapy (HAT) in adult patients with cystic fibrosis: a feasibility study.

This study was designed to investigate the efficacy, safety and patients' acceptance of a novel system for sputum clearance--Hydro Acoustic Therapy (HAT) in patients with cystic fibrosis (CF). This is a prospective crossover study where 18 patients received 6 sessions of physiotherapy over 6 separate days. These consisted of 2 sessions of either HAT, flutter valve or and sitting in the bath with sounds without vibration (placebo) for 30 minutes each. The efficacy was investigated by measuring the weight of wet and dry sputum after each session and by change in spirometry values. The preference was assessed by a questionnaire completed by patients at the end of the study about their preference of which type of physiotherapy received. The weight of both dry and wet sputum produced was similar in the 3 arms of the study. Spirometry values but not oxygen saturation were reduced after HAT and flutter therapy sessions. HAT therapy was preferred to flutter and placebo in terms of breathlessness, ease of sputum production and relaxation. Of the patients, 70% stated that they would choose HAT as their preferred physiotherapy method compared to 0% for flutter (χ(2) = 20.3, p < 0.0001). There were no procedure-related complications in any of the 3 arms of the study. HAT was found to be safe, well tolerated and favoured by the majority of CF patients. The effect of HAT, however, on sputum production was not superior to flutter or placebo.