Comparison of 7 Oscillatory Positive Expiratory Pressures With Respect to Differences in Rheological Properties and Lung Mechanics

Abstract

Background: Oscillating positive expiratory pressure (OPEP) device promotes airway clearance in many respiratory diseases. However, the effects differ depending on the device, so we bench tested 7 devices to compare the migration distance of mucus simulants (MS) with different lung mechanics and viscoelasticity.

Methods: We measured the movement distance of the MS in PCV A/C mode, Inspiratory pressure 15 cm H₂O, i-time 1 sec, PEEP 0 cm H₂O, frequency 5 breaths/min, under the four types of lung mechanics (normal, obstructive, restrictive, and mixed lung disorder by using Michigan TTL). The movement distance was measured using two types of MS. A 1% lysis of MS is potage-like, corresponding to the secretion of chronic bronchitis, and a 4% lysis MS is jelly-like, close to the viscoelasticity of a mucus plug during an asthma attack. The 7 OPEP devices used were Aerobika, Vibra PEP, Acapella DM, Acapella DH, Acapella Duet, Flutter, and Vibralung. The analysis of the ventilatory dynamics was measured 10 times under each condition using flow analyzer PF300, and the average value was compared. Data analysis used software SPSS version 22 and P values < .05 were considered statistically significant. This research is conducted after obtaining approval from Kochi Professional University of Rehabilitation Ethics Review Board.

Results: 1) Vibralung, which uses sound waves, can be used even when spontaneous breathing is weak. It differed from other OPEP devices in that the moving distance of MS was significantly greater (P < .001). 2) In OPEP devices other than Vibralung, the moving distance of MS was significantly greater in the order of Aerobika, Vibra PEP (P < .001). 3) In changes lung mechanics, the movement distance of MS increased in the order of normal lung, restrictive lung, obstructive lung and mixed lung(P < .001). Movement distance of MS was greater in restrictive lung than in obstructive lung (P < .001). 4) There was no difference between Acapella and Flutter in moving distance. 5) Compared to 1% artificial sputum, 4% viscoelastic sputum moved less (P < .001).

Conclusions: 1) Among the OPEP devices, Vibralung, which mechanically generates sound waves, seemed to be different from other OPEP devices. 2) Among the OPEP devices, Aerobika, which had the highest Oscillation Index (oscillation frequency multiplied by vibration amplitude) and a long MS movement distance, was thought to be the most effective.