title: Pressure-Relief Features of Fixed and Autotitrating Continuous Positive Airway Pressure May Impair Their Efficacy: Evaluation with a Respiratory Bench Model.
abstract: OBJECTIVE
  Pressure-relief features are aimed at improving the patient's comfort during continuous positive airway pressure (CPAP) treatment for obstructive sleep apnea. The objective of this study was to determine the effect of these therapy features on fixed CPAP and autotitrating CPAP (APAP) treatment efficacy.
  
  
  METHODS
  Seven pressure-relief features applied by three CPAP devices were included in our study (Remstar Auto: C-Flex 3, C-Flex+ 3, A-Flex 3, P-Flex; AirSense 10: EPR 3; Prisma 20A: SoftPAP 2 and 3). In fixed CPAP, the devices were subjected to a 10-min bench-simulated obstructive apnea sequence (initial apnea-hypopnea index, AHI = 60/h) with and without pressure-relief features. In APAP, the sequence was lengthened to 4.2 h (initial AHI = 58.6/h). The residual AHI and mean/median pressure were compared with and without pressure-relief features.
  
  
  RESULTS
  Compared to conventional CPAP, where pressure was adjusted to be just sufficient to control the simulated obstructive events, C-Flex+ 3, P-Flex, and EPR 3 failed to normalize the breathing flow and did not reduce the AHI. The mean pressures with the three features, respectively, were 1.8, 2.6, and 2.6 cmH2O lower than the conventional CPAP. Compared to conventional APAP, similar levels of control were observed with pressure-relief features, apart from P-Flex where the delivered mean pressure was lower and residual AHI greater. The device-reported mean/median pressures in APAP with A-Flex 3, P-Flex, EPR 3, and SoftPAP 3 were higher than that measured on the bench.
  
  
  CONCLUSIONS
  Pressure-relief features may attenuate CPAP efficacy if not adjusted for at the time of their introduction. In clinical practice, efficacy can be ensured by increasing the therapeutic pressure delivered by fixed CPAP or by enabling the pressure-relief features prior to initial pressure titration. Device-reported pressures in APAP devices with pressure relief activated may overstate delivered pressures.
authors.affiliation: Air Liquide Healthcare, Gentilly, France.|Sleep Disorders Center, AP-HP Antoine-Béclère Hospital, Clamart, France.|Faculty of Pharmacy, Paris-Sud University, Châtenay-Malabry, France.
authors.forename: Kaixian
authors.initials: K
authors.lastname: Zhu
authors.affiliation: Air Liquide Healthcare, Gentilly, France.
authors.forename: Sami
authors.initials: S
authors.lastname: Aouf
authors.affiliation: Sleep Disorders Center, AP-HP Antoine-Béclère Hospital, Clamart, France.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Roisman
authors.affiliation: Sleep Disorders Center, AP-HP Antoine-Béclère Hospital, Clamart, France.|Faculty of Pharmacy, Paris-Sud University, Châtenay-Malabry, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Escourrou
mesh_terms: D045422:Continuous Positive Airway Pressure / Q000295:instrumentation* / Q000379:methods*; D004867:Equipment Design; D008954:Models, Biological; D011312:Pressure; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology* / Q000628:therapy*; D016896:Treatment Outcome
keywords: CPAP treatment; bench test; pressure-relief features