Evaluation of auto bi-level algorithm to treat pressure intolerance in obstructive sleep apnea

Nigel Ball, Nancy Gordon, Eileen Casal, James Parish

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Purpose: 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 2O ± 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 2O vs. 14.1 cm H 2O, 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.

Original languageEnglish (US)
Pages (from-to)301-309
Number of pages9
JournalSleep and Breathing
Issue number3
StatePublished - Sep 2011


  • Auto bi-level positive airway pressure
  • Bi-level positive airway pressure
  • Obstructive sleep apnea
  • Sleep apnea

ASJC Scopus subject areas

  • Otorhinolaryngology
  • Clinical Neurology


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