title: Continuous positive airway pressure requirement during the first month of treatment in patients with severe obstructive sleep apnea.
abstract: OBJECTIVE
  (1) To compare the continuous positive airway pressure (CPAP) requirement at the time of diagnosis (T0), after 2 weeks (T2), and after 4 weeks (T4) of CPAP treatment, in patients with severe obstructive sleep apnea (OSA); and (2) to assess whether any alteration in CPAP requirement over the first 4 weeks of CPAP treatment would influence daytime alertness, subjective sleepiness, or mood.
  
  
  METHODS
  A prospective, controlled, single-blind crossover study.
  
  
  METHODS
  University teaching hospital.
  
  
  METHODS
  Ten patients with newly diagnosed and previously untreated severe OSA (aged 52+/-9 years, apnea hypopnea index [AHI] of 99+/-31) and subsequently 10 control patients (aged 52+/-11 years, AHI 85+/-17).
  
  
  METHODS
  Overnight polysomnography with CPAP titration to determine the CPAP requirement, which was standardized for body position and sleep stage, on all three occasions (T0, T2, T4). Objective sleep quality, daytime alertness, subjective sleepiness (Epworth Sleepiness Scale), and mood (Hospital Anxiety and Depression Scale).
  
  
  RESULTS
  CPAP requirement decreased from T0 to T2 (median difference, 1.5 cm H2O, 95% confidence interval [CI], 1.1 to 2.7 cm H2O, p=0.0004) and did not differ between T2 and T4. Use of the lower CPAP pressure during T2 to T4 was associated with a decrease in Epworth scale (mean difference, 2.6, 95% CI, 1.2 to 4; p=0.01) and anxiety (median change, 2; 95% CI, 0.5 to 2.9, p=0.03) scores, as compared with the first 2 weeks. Daytime alertness did not differ between T0 to T2 and T2 to T4.
  
  
  CONCLUSIONS
  CPAP requirement falls within 2 weeks of starting CPAP treatment. A change to the lower required CPAP was not associated with any deterioration in daytime alertness but was associated with small subjective improvements in sleepiness and mood.
authors.affiliation: Division of Respiratory Medicine, University of Saskatchewan, Saskatoon, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Jokic
authors.forename: A
authors.initials: A
authors.lastname: Klimaszewski
authors.forename: G
authors.initials: G
authors.lastname: Sridhar
authors.forename: M F
authors.initials: MF
authors.lastname: Fitzpatrick
mesh_terms: D018592:Cross-Over Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D017286:Polysomnography; D011175:Positive-Pressure Respiration / Q000379:methods / Q000592:standards; D011187:Posture / Q000502:physiology; D011446:Prospective Studies; D012720:Severity of Illness Index; D016037:Single-Blind Method; D012891:Sleep Apnea Syndromes / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D012895:Sleep, REM; D016896:Treatment Outcome; D014851:Wakefulness / Q000502:physiology