title: Evaluation of unattended automated titration to determine therapeutic continuous positive airway pressure in patients with obstructive sleep apnea.
abstract: BACKGROUND
  Determination of the therapeutic pressure during continuous positive airway pressure (CPAP) therapy is usually performed by a technician during polysomnography. In recent years, several devices for automated adjustment of the therapeutic pressure by the means of computerized algorithms were developed. The aims of the present study were to compare two different devices for automated titration and to verify if unattended automated titration is a feasible strategy to determine the therapeutic CPAP.
  
  
  METHODS
  We enrolled 16 consecutive patients with obstructive sleep apnea syndrome (OSAS) defined by an apnea-hypopnea index > 20/h. Automated titration was performed in the hospital using two CPAP devices (Autoset; Resmed; North Ryde, Australia; and Somnosmart; Weinmann; Hamburg, Germany) in random order for 2 consecutive nights, based on different signals for the detection of respiratory events. During titration, there was no direct supervision by a technician, and polysomnography was not recorded. We defined the therapeutic pressure as the 95th percentile of the airway pressure over time (P95).
  
  
  RESULTS
  We observed significant differences of the P95 between the two devices, with an average of 7.0 +/- 2.5 cm H(2)O for the Somnosmart and 9.9 +/- 2.6 cm H(2)O for the Autoset (p = 0.005) [mean +/- SD]. There was a considerable lack of agreement between the two devices, with a bias of 3.0 cm H(2)O and limits of agreement ranging from + 9.3 to - 3.2 cm H(2)O. We found no significant correlation between the paired differences of P95 and either indexes of severity of OSAS or lung function variables.
  
  
  CONCLUSIONS
  Automated titration based on the analyses of flow (Autoset) or forced oscillations (Somnosmart) predicted significant different therapeutic pressures for fixed CPAP therapy. Thus, unattended automated titration performed during 1 night of hospital stay with commercially available devices cannot be used to determine accurately the therapeutic CPAP in patients with OSAS.
authors.affiliation: Service de Pneumologie, Hôpital de Hautepierre, Hôpitaux Universitaires de Strasbourg, France. romain.kessler@chru-strasbourg.fr
authors.forename: Romain
authors.initials: R
authors.lastname: Kessler
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Weitzenblum
authors.forename: Ari
authors.initials: A
authors.lastname: Chaouat
authors.forename: Carmen
authors.initials: C
authors.lastname: Iamandi
authors.forename: Thierry
authors.initials: T
authors.lastname: Alliotte
mesh_terms: D001331:Automation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods*; D011175:Positive-Pressure Respiration / Q000295:instrumentation* / Q000379:methods*; D015203:Reproducibility of Results; D020181:Sleep Apnea, Obstructive / Q000628:therapy*; D018709:Statistics, Nonparametric; D017186:Titrimetry