title: Risk factors for nocturnal hypoxemia in severe obstructive sleep apnea patients.
abstract: BACKGROUND
  Severe obstructive sleep apnea (sOSA) and oxygen desaturations are both risk factors for postoperative complications. In some but not all patients, sOSA is associated with frequent oxygen desaturation episodes during sleep. The aim of this retrospective study was to identify the risk factors for exhibiting oxygen desaturation in patients with sOSA.
  
  
  METHODS
  Records of 786 patients, mainly obese (Body Mass Index [mean+SD]=30.2+6.0 kg/m2), were analyzed. Univariate and multivariate analyzes were applied to identify predictive risk factors for oxygen desaturation. Prediction probability was used to test the association between potential risk factors (obesity, age, gender, smoking, alcohol consumption, and benzodiazepines use) and the combination of sOSA and oxygen desaturation. A P value <0.05 was considered as statistically significant.
  
  
  RESULTS
  Univariate and multivariate analyses identified five risk factors for oxygen desaturation in the whole population: age (P<0.001), obesity (P<0.001), benzodiazepine use (P<0.001), smoking (P=0.016), and male gender (P=0.029). The same analyses applied to patients with sOSA identified two independent risk factors for oxygen desaturation: obesity (P<0.001), and benzodiazepine use (P=0.017). Obesity obtains the best prediction probability [95% CI] for the combination of sOSA and oxygen desaturation: 0.74 [0.69-0.79]. A BMI >49 kg/m2 was associated with a 50% probability of combining severe OSA and nocturnal oxygen desaturation.
  
  
  CONCLUSIONS
  Less than 50% of patients with sOSA experience nocturnal oxygen desaturation. Obesity and daily benzodiazepine intake are independent risk factors for these patients to exhibit nocturnal oxygen desaturation. Benzodiazepine in obese patients with sOSA should, therefore, be used cautiously.
authors.affiliation: Department of Anesthesia, Clinique Saint-Luc of Bouge, Namur, Belgium - eric.deflandre@gmail.com.|Cabinet Medical ASTES, Jambes, Belgium - eric.deflandre@gmail.com.|University of Liege, Liege, Belgium - eric.deflandre@gmail.com.
authors.forename: Eric
authors.initials: E
authors.lastname: Deflandre
authors.affiliation: Department of Anesthesia, University Hospital of Liege, University of Liege, Liege, Belgium.
authors.forename: Damien
authors.initials: D
authors.lastname: Kempeneers
authors.affiliation: Cabinet Medical ASTES, Jambes, Belgium.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Degey
authors.affiliation: Department of Neurology, University Hospital of Liege, University of Liege, Liege, Belgium.
authors.forename: Robert
authors.initials: R
authors.lastname: Poirrier
authors.affiliation: Department of Pneumology, Clinique Saint-Luc of Bouge, Namur, Belgium.
authors.forename: Pascal
authors.initials: P
authors.lastname: Legros
authors.affiliation: Department of Anesthesia and Intensive Care Medicine, University Hospital of Liege, Liege, Belgium.
authors.forename: Jean-Francois
authors.initials: JF
authors.lastname: Brichant
authors.affiliation: Department of Anesthesia and Intensive Care Medicine, University Hospital of Liege, Liege, Belgium.
authors.forename: Jean
authors.initials: J
authors.lastname: Joris
mesh_terms: D005260:Female; D006801:Humans; D000860:Hypoxia / Q000453:epidemiology / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000150:complications*