title: Evaluation of Functional Characteristics of 4 Oscillatory Positive Pressure Devices in a Simulated Cystic Fibrosis Model.
abstract: BACKGROUND
  Oscillatory positive expiratory pressure (OPEP) is an airway clearance therapy that delivers positive pressure and air-flow oscillations during exhalation. This study described functional characteristic differences of 4 OPEP devices during an active exhalation in a simulated model. We hypothesized peak pressure (Ppeak), positive expiratory pressure (PEP), oscillatory frequency (f), and pressure amplitude will differ, depending upon the device used, device resistance setting, and time (repeated consecutive active exhalations through the device).
  
  
  METHODS
  The ASL 5000 was scripted to simulate pulmonary mechanics of a pediatric cystic fibrosis patient with moderate to severe lung disease. Airway resistance was standardized at 17.1 cm H2O/L/s, pulmonary compliance at 42.1 mL/cm H2O, active exhalation at 22 breaths/min, and tidal volume at 409 mL. Resistance settings for the Acapella, RC-Cornet, Flutter, and Aerobika were adjusted to low, medium, and high. Values for f, Ppeak, PEP, and pressure amplitude were recorded for 1 min and graphically displayed.
  
  
  RESULTS
  Significant effects for time, device, and resistance (P< .01) were noted for Ppeak, PEP, and pressure amplitude at each resistance level, demonstrating that the devices functioned differently as more than one repetition of a series of consecutive active exhalations are performed. Significant interaction effects for device, resistance level, and time indicate inconsistent output for Ppeak (P< .01), PEP (P< .01), and pressure amplitude (P< .01). Oscillatory f values fell within the respective manufacturers' operational parameters. The Aerobika provided the most consistent pressure amplitude across resistance settings and produced the highest mean pressure amplitude at medium and high resistance settings.
  
  
  CONCLUSIONS
  Statistically significant and clinically relevant variations in Ppeak, PEP, and pressure amplitude occurred between devices and within a device, as the resistance setting changed. The combination of device, time, and resistance settings affects OPEP device output for pressure, amplitude, and oscillatory frequency. Functional variations may impact therapeutic effectiveness, warranting additional study to determine clinical impact.
authors.affiliation: Division of Respiratory Care, Rush University College of Health Sciences, Chicago, Illinois and the Department of Respiratory Care, Dayton Children's Hospital, Dayton, Ohio.
authors.forename: Hillary
authors.initials: H
authors.lastname: Van Fleet
authors.affiliation: Department of Respiratory Care.
authors.forename: Diane K
authors.initials: DK
authors.lastname: Dunn
authors.affiliation: Rebecca D Considine Research Institute.
authors.forename: Neil L
authors.initials: NL
authors.lastname: McNinch
authors.affiliation: Nursing Administration, Akron Children's Hospital, Akron, Ohio. tvolsko@chmca.org.
authors.forename: Teresa A
authors.initials: TA
authors.lastname: Volsko
mesh_terms: D000403:Airway Resistance; D035641:Chest Wall Oscillation / Q000295:instrumentation*; D002648:Child; D003198:Computer Simulation; D003550:Cystic Fibrosis / Q000503:physiopathology / Q000628:therapy*; D045853:Exhalation; D006801:Humans; D010366:Peak Expiratory Flow Rate; D011175:Positive-Pressure Respiration / Q000295:instrumentation*; D013990:Tidal Volume
keywords: OPEP; airway clearance; simulated model