title: Randomized controlled trial of variable-pressure versus fixed-pressure continuous positive airway pressure (CPAP) treatment for patients with obstructive sleep apnea/hypopnea syndrome (OSAHS).
abstract: OBJECTIVE
  To determine whether fixed-pressure or variable-pressure CPAP was preferred by patients and gave better outcomes in patients with the obstructive sleep apnea/hypopnea syndrome (OSAHS).
  
  
  METHODS
  Randomized blinded cross-over trial with 6 weeks of fixed and 6 weeks of variable-pressure CPAP.
  
  
  METHODS
  Sleep center.
  
  
  METHODS
  200 consecutive consenting CPAP naïve patients with daytime sleepiness and > 15 apneas + hypopneas/h after an attended auto-CPAP titration night.
  
  
  METHODS
  CPAP therapy using the same device (Autoset Spirit) set for 6 weeks in fixed pressure mode and for 6 weeks in variable pressure mode, the order of therapies being randomized.
  
  
  RESULTS
  All measurements were recorded at the end of each limb by a researcher blind to treatment. These included symptoms, Epworth Score, CPAP usage, objective sleepiness by modified Osler test, vigilance and health related quality of life. A total of 181 of 200 patients completed the study. At the end of the study, patients expressed no significant difference in the primary outcome, patient preference, 72 patients preferring fixed and 69 preferring variable-pressure CPAP. Epworth score was lower on variable (9.5, SEM 0.4) than fixed-pressure CPAP (10.0, SEM 0.3; P = 0.031). Mean CPAP use was higher on variable (4.2, SEM 0.2 h/night) than fixed-pressure CPAP (4.0, SEM 0.2 h/night; P = 0.047). There were no other significant differences between treatments. CONCLUSIONS This study shows no difference in patient preference and only a marginal benefit of variable over fixed-pressure CPAP in OSAHS in terms of subjective sleepiness and CPAP use. The clinical value of this difference remains to be determined.
  
  
  BACKGROUND
  Variable-pressure versus fixed-pressure continuous positive airway pressure (CPAP) treatment for patients with obstructive sleep apnoea/hypopnoea syndrome (OSAHS); Registration # ISRCTN43085025.http://www.controlled-trials.com//SRCTN43085025.
authors.affiliation: Department of Sleep Medicine, Royal Infirmary of Edinburgh, Edinburgh, UK. m.vennelle@ed.ac.uk
authors.forename: Marjorie
authors.initials: M
authors.lastname: Vennelle
authors.forename: Sandra
authors.initials: S
authors.lastname: White
authors.forename: Renata L
authors.initials: RL
authors.lastname: Riha
authors.forename: Tom W
authors.initials: TW
authors.lastname: Mackay
authors.forename: Heather M
authors.initials: HM
authors.lastname: Engleman
authors.forename: Neil J
authors.initials: NJ
authors.lastname: Douglas
mesh_terms: D000328:Adult; D000368:Aged; D000399:Air Pressure; D045422:Continuous Positive Airway Pressure / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010349:Patient Compliance / Q000706:statistics & numerical data; D017060:Patient Satisfaction; D020181:Sleep Apnea, Obstructive / Q000628:therapy*; D014600:Utilization Review / Q000706:statistics & numerical data