title: Impact of different backup respiratory rates on the efficacy of noninvasive positive pressure ventilation in obesity hypoventilation syndrome: a randomized trial.
abstract: BACKGROUND
  Unintentional leaks, patient-ventilatory asynchrony, and obstructive or central events (either residual or induced by noninvasive positive pressure ventilation [NPPV]) occur in patients treated with NPPV, but the impact of ventilator settings on these disturbances has been little explored. The objective of this study was to investigate the impact of backup respiratory rate (BURR) settings on the efficacy of ventilation, sleep structure, subjective sleep quality, and respiratory events in a group of patients with obesity hypoventilation syndrome (OHS).
  
  
  METHODS
  Ten stable patients with OHS treated with long-term nocturnal NPPV underwent polysomnographic recordings and transcutaneous capnography on 3 consecutive nights with three different settings for BURR in random order: spontaneous (S) mode, low BURR, and high BURR. No other ventilator parameter was modified.
  
  
  RESULTS
  The S mode was associated with the occurrence of a highly significant increase in respiratory events, mainly of central and mixed origin, when compared with both spontaneous/timed (S/T) modes. Accordingly, the oxygen desaturation index was significantly higher in the S mode than in either of the S/T modes. The results of nocturnal transcutaneous P(CO(2)) (Ptc(CO(2))) (mean value and time spent with Ptc(CO(2)) > 50 mm Hg) were similar over the three consecutive nocturnal recordings. The quality of sleep was perceived as slightly better, and the number of perceived arousals as lower with the low- vs high-BURR (S/T) mode.
  
  
  CONCLUSIONS
  In a homogenous group of patients treated with long-term NPPV for obesity-hypoventilation, changing BURR from an S/T mode with a high or low BURR to an S mode was associated with the occurrence of a highly significant increase in respiratory events, of mainly central and mixed origin.
  
  
  BACKGROUND
  ClinicalTrials.gov; No.: NCT01130090; URL: www.clinicaltrials.gov
authors.affiliation: Division of Pulmonary Diseases, Department of Psychiatry, Geneva University Hospitals, Geneva, Switzerland. Electronic address: olivier.contal@hcuge.ch.
authors.forename: Olivier
authors.initials: O
authors.lastname: Contal
authors.affiliation: Division of Pulmonary Diseases, Department of Psychiatry, Geneva University Hospitals, Geneva, Switzerland.
authors.forename: Dan
authors.initials: D
authors.lastname: Adler
authors.affiliation: AGIR a dom, Recherche et Développement, Meylan, France.
authors.forename: Jean-Christian
authors.initials: JC
authors.lastname: Borel
authors.affiliation: Sleep Laboratory, Department of Psychiatry, Geneva University Hospitals, Geneva, Switzerland.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Espa
authors.affiliation: Sleep Laboratory, Department of Psychiatry, Geneva University Hospitals, Geneva, Switzerland.
authors.forename: Stephen
authors.initials: S
authors.lastname: Perrig
authors.affiliation: Service de pneumologie et Centre de médecine du sommeil, Cliniques Universitaires Saint Luc, Université Catholique de Louvain, Brussels, Belgium.
authors.forename: Daniel
authors.initials: D
authors.lastname: Rodenstein
authors.affiliation: Sleep Laboratory, Department of Psychiatry, Geneva University Hospitals, Geneva, Switzerland; Institut National de la Santé et de la Recherche Médical, University Hospital, Grenoble, France; Service de pneumologie et Centre de médecine du sommeil, Cliniques Universitaires Saint Luc, Université Catholique de Louvain, Brussels, Belgium.
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Pépin
authors.affiliation: Division of Pulmonary Diseases, Department of Psychiatry, Geneva University Hospitals, Geneva, Switzerland.
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Janssens
mesh_terms: D001785:Blood Gas Monitoring, Transcutaneous; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D063087:Noninvasive Ventilation / Q000379:methods*; D010845:Obesity Hypoventilation Syndrome / Q000628:therapy*; D017286:Polysomnography; D011175:Positive-Pressure Respiration / Q000379:methods*; D056152:Respiratory Rate