title: Evaluation of auto bi-level algorithm to treat pressure intolerance in obstructive sleep apnea.
abstract: OBJECTIVE
  The objective of this study was to evaluate whether a new auto-adjusting bi-level algorithm was comparable to a standard method for prescribing bi-level therapy.
  
  
  METHODS
  This study was a prospective randomized, double-blinded crossover evaluation of the equivalency of the auto-adjusting bi-level mode (VAuto™) compared to standard bi-level mode, using a pre-determined difference in Apnea-Hypopnea Index (AHI) of five events per hour. Data were obtained during sleep studies performed on two separate nights. Twenty-two subjects met the entry criteria and were enrolled in the study at four investigational sites in the USA.
  
  
  RESULTS
  Mean AHI for the auto-adjusting bi-level mode was 6.2 ± 5.4 events per hour and for the standard bi-level mode 8.3 ± 5.8 events per hour. The AHI for the two modes were clinically equivalent. The difference in median pressure between these two modes was -3.8 cm H(2)O ± 3.6 (p = 0.0008) in favor of the auto-adjusting bi-level mode. In addition, the maximum pressure was significantly higher in the auto-adjusting bi-level mode (16.0 cm H(2)O vs. 14.1 cm H(2)O, p = 0.02).
  
  
  CONCLUSIONS
  Our results demonstrated that the auto-adjusting bi-level mode normalized AHI comparable to the standard bi-level mode. The results of this study have several significant implications for the clinical management of sleep apnea. Obstructive sleep apnea (OSA) is a common condition and is associated with untoward complications. Non-compliance with positive airway pressure (PAP) limits the efficacy of the PAP therapy. The auto-adjusting bi-level mode provides a potentially reliable alternative for sleep clinicians faced with prescribing bi-level PAP for non-compliant patients. This study documents that this type of auto-adjusting device provides effective treatment of OSA.
authors.affiliation: Swedish Medical Center, Seattle, WA, USA.
authors.forename: Nigel
authors.initials: N
authors.lastname: Ball
authors.forename: Nancy
authors.initials: N
authors.lastname: Gordon
authors.forename: Eileen
authors.initials: E
authors.lastname: Casal
authors.forename: James
authors.initials: J
authors.lastname: Parish
mesh_terms: D000328:Adult; D000368:Aged; D000399:Air Pressure; D000465:Algorithms; D045422:Continuous Positive Airway Pressure / Q000295:instrumentation*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D045853:Exhalation / Q000502:physiology; D005260:Female; D006801:Humans; D001239:Inhalation / Q000502:physiology; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D017286:Polysomnography; D011446:Prospective Studies; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology / Q000628:therapy*; D013813:Therapy, Computer-Assisted / Q000295:instrumentation*