title: Evaluation of Pressure Generated by Resistors From Different Positive Expiratory Pressure Devices.
abstract: BACKGROUND
  Breathing exercises with positive expiratory pressure (PEP) are used to improve pulmonary function and airway clearance. Different PEP devices are available, but there have been no studies that describe the pressure generated by different resistors. The purpose of this study was to compare pressures generated from the proprietary resistor components of 4 commercial flow-dependent PEP valves with all other parameters kept constant.
  
  
  METHODS
  Resistors from 4 flow-regulated PEP devices (Pep/Rmt system, Wellspect HealthCare; Pipe P breathing exerciser, Koo Medical Equipment; Mini-PEP, Philips Respironics [including resistors by Rüsch]; and 15-mm endo-adapter, VBM Medizintechnik) were tested randomly by a blinded tester at constant flows of 10 and 18 L/min from an external gas system. All resistors were tested 3 times.
  
  
  RESULTS
  Resistors with a similar diameter produced statistically significant different pressures at the same flow. The differences were smaller when the flow was 10 L/min compared with 18 L/min. The differences were also smaller when the diameter of the resistor was increased. The pressures produced by the 4 resistors of the same size were all significantly different when measuring 1.5- and 2.0-mm resistors at a flow of 10 L/min and 2.0-mm resistors at a flow of 18 L/min (P < .001). There were no significant differences between any of the resistors when testing sizes of 4.5 and 5.0 mm at either flow. The Mini-PEP and adapter resistors gave the highest pressures.
  
  
  CONCLUSIONS
  Pressures generated by the different proprietary resistor components of 4 commercial PEP devices were not comparable, even though the diameter of the resistors is reported to be the same. The pressures generated were significantly different, particularly when using small-diameter resistors at a high flow. Therefore, the resistors may not be interchangeable. This is important information for clinicians, particularly when considering PEP for patients who do not tolerate higher pressures.
authors.affiliation: Department of Gastrosurgical Research and Education, Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden. Department of Physical Therapy, Sahlgrenska University Hospital and Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden. monika.fagevik-olsen@vgregion.se.
authors.forename: Monika
authors.initials: M
authors.lastname: Fagevik Olsén
authors.affiliation: Department of Physical Therapy, Sahlgrenska University Hospital and Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden.
authors.forename: Maria
authors.initials: M
authors.lastname: Carlsson
authors.affiliation: Chalmers University of Technology, Gothenburg, Sweden.
authors.forename: Erik
authors.initials: E
authors.lastname: Olsén
authors.affiliation: Department of Medical Sciences, Clinical Physiology, Uppsala University, Uppsala, Sweden, and the Faculty of Medicine and Health, Surgery, Örebro University, Örebro, Sweden.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Westerdahl
mesh_terms: D004867:Equipment Design; D045853:Exhalation; D006801:Humans; D008422:Materials Testing; D011175:Positive-Pressure Respiration / Q000295:instrumentation*; D011312:Pressure
keywords: breathing exercises; positive expiratory pressure; resistance breathing