Technical Aspects of Devices and Equipment for Positive Expiratory Pressure With and Without Oscillation.

Background: Breathing exercises with positive expiratory pressure (PEP) and oscillating PEP are common treatments for patients with respiratory impairments. There are several trials evaluating the clinical effects of a variety of commercially available and self-made devices. There is a lack of evaluation concerning technical aspects and construction of the devices. The aims of this review were to describe and compare technical aspects of devices and equipment used for PEP and oscillating PEP as a basis for clinical decisions regarding prescriptions.

Methods: In this systematic review, we included trials evaluating different technical aspects of devices and equipment for PEP and oscillating PEP until June 2019. The literature search was performed in PubMed, CINAHL, Cochrane Library, Embase and PEDro.

Results: The literature search resulted in 812 studies, which, after being read by 2 independent reviewers, were reduced to 21 trials that matched the inclusion criteria. The achieved PEP is dependent on the given resistance or achieved expiratory flow through the devices and their separate parts. Oscillation frequency in oscillating PEP devices affects the pressure and oscillation amplitude and flow. For some devices, the device's position also has an impact on the outcome. There are similarities and differences among all of the devices, and the equipment components are not interchangeable without changing the achieved PEP levels.

Conclusions: Many devices are available to provide PEP and oscillating PEP treatment. These devices differ substantially in design as well as in performance. When using PEP devices, it is important to understand how all parts of the devices affect outcomes. An increased understanding of how PEP is produced for the spontaneously breathing patient is important to achieve desired treatment effects.