title: The effects of Provent on moderate to severe obstructive sleep apnoea during continuous positive airway pressure therapy withdrawal: a randomised controlled trial.
abstract: OBJECTIVE
  The aim of this study was to test the effectiveness of Provent, an expiratory nasal resistance valve, to prevent the recurrence of OSA following CPAP withdrawal.
  
  
  METHODS
  Randomised, partially blinded, parallel, placebo-controlled trial.
  
  
  METHODS
  Outpatient sleep clinics in the UK (Oxford) and Switzerland (Zurich).
  
  
  METHODS
  67 patients with OSA receiving CPAP were randomised to one of three groups for 2 weeks: continuing CPAP, Provent or placebo Provent.
  
  
  METHODS
  Primary outcomes included for Provent versus placebo Provent, OSA severity (oxygen desaturation index (ODI), apnoea-hypopnoea index (AHI)) and Epworth Sleepiness Scale (ESS) score. Secondary outcomes for Provent versus placebo Provent included ODI from ambulatory pulse oximetry and blood pressure (BP). For CPAP versus Provent, or CPAP versus placebo Provent, secondary outcomes included ODI/AHI, ESS and BP.
  
  
  RESULTS
  63 patients were included in the per protocol analysis. OSA recurred in the Provent (ODI 35.8, SD 17.4) and placebo Provent (ODI 28.2, SD 18.3) groups, and there was no significant difference in ODI, AHI and ESS between Provent and placebo Provent at 2 weeks (mean difference ODI -1.0, 95% CI -10.0 to +12.0, p=0.85; AHI +3.2, 95% CI -7.7 to +14.1, p=0.52; and ESS -1.4, 95% CI -4.1 to +1.4, p=0.33). ODI from ambulatory pulse-oximetry and BP at 2 weeks were not different in the Provent versus placebo Provent groups. ODI, AHI and BP, but not ESS, were significantly higher in the Provent and placebo Provent groups compared with CPAP.
  
  
  CONCLUSIONS
  Provent cannot be recommended as an alternative short-term therapy for patients with moderate to severe OSA already on CPAP.
  NCT01332175.
authors.affiliation: Sleep Disorders Centre and Pulmonary Division, University Hospital of Zurich, Zurich, Switzerland.
authors.forename: Valentina A
authors.initials: VA
authors.lastname: Rossi
authors.forename: Barbara
authors.initials: B
authors.lastname: Winter
authors.forename: Najib M
authors.initials: NM
authors.lastname: Rahman
authors.forename: Ly-Mee
authors.initials: LM
authors.lastname: Yu
authors.forename: Janet
authors.initials: J
authors.lastname: Fallon
authors.forename: Christian F
authors.initials: CF
authors.lastname: Clarenbach
authors.forename: Konrad E
authors.initials: KE
authors.lastname: Bloch
authors.forename: John R
authors.initials: JR
authors.lastname: Stradling
authors.forename: Malcolm
authors.initials: M
authors.lastname: Kohler
mesh_terms: D000368:Aged; D001794:Blood Pressure; D045422:Continuous Positive Airway Pressure; D006970:Disorders of Excessive Somnolence / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009666:Nose; D010092:Oximetry; D010100:Oxygen / Q000097:blood; D017286:Polysomnography; D019736:Prostheses and Implants; D012008:Recurrence; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000628:therapy*; D011795:Surveys and Questionnaires; D028761:Withholding Treatment
chemical_list: D010100:Oxygen
keywords: Sleep apnoea