Mechanical analysis of an oscillatory positive expiratory pressure device used in respiratory rehabilitation

This article aims to characterize the mechanical behavior of the Acapella^® Blue, a respiratory rehabilitation device designed to aid sputum clearance. In this scope, the present study initially describes in detail the peak-to-peak oscillation amplitude (App) and peak frequency (fp) behavior, as well as positive pressure level (Ppl), in the flow range more comonly found in practice. The parameters were evaluated in all 5 adjustment levels of the equipment in intervals of 50 mL/s. The device characterization has shown fp up to 23 Hz, App from 0.2 to 2.8 cmH₂O and Ppl ranging from 1.2 to 13.5 cmH₂O. The studied device may produce oscillation in the ranges of ciliary movements and respiratory system resonance frequency of patients with respiratory diseases. Data obtained in this work may help to optimize the use of the Acapella^® Blue device in respiratory rehabilitation. Suggestions for the practical use of the device are also presented.