OBJECTIVE: Flutter VRP1 is a device that utilises high-frequency oscillation and positive expiratory pressure to prevent mucus stasis, aid removal, and treat pulmonary atelectasis. Whether these effects are due to changes in the rheological properties of the bronchial mucus remains controversial. This pilot study examined the techniques available to determine whether the use of Flutter VRP1 in a single session by patients with bronchiectasis altered properties related to transport of tracheobronchial mucus and investigated the effect of high-frequency oscillations and positive expiratory pressure (PEP) on these alterations. DESIGN: Pilot observational, single cohort study. SETTING: Outpatient department. PARTICIPANTS: Eight outpatients with bronchiectasis with daily expectoration of over one tablespoon of sputum. INTERVENTION: Participants underwent two procedures at random on different days: PEP and Flutter VRP1 exercises compared to a control (no exercise) period. MAIN OUTCOME MEASURE: Three sputum samples were collected after expectoration by voluntary coughing: at baseline, 20 and 40 min after using Flutter VRP1 or PEP, or without sny procedure (control). The samples were analysed on the basis of relative transport velocity, contact angle measurement and displacement in a simulated cough machine. RESULTS: The results were similar for the three groups and across the three measurements for each group, however, the measurement of transport velocity appeared relatively sensitive to change in group (Flutter VRP1 median 0.6, 95% confidence interval 0.53 to 0.73; PEP median 0.78, 95% confidence interval 0.53 to 0.92; control median 0.63, 95% confidence interval 0.51 to 0.79). Contact angle of the mucus and displacement of the mucus in a simulated cough machine demonstrated weal trends, although these were not consistent for the three groups. Calculations based on these results illustrated the number of subjects required in a full scale clinical trial. CONCLUSIONS: The use of Flutter VRP1 and PEP by patients with bronchiectasis for up to 40 min in a single session did not appear to change ciliary or cough transportability of bronchial mucus, or contact angle measurements. However, the use of these measurements techniques proved feasible in this population.

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