title: Unanticipated Nocturnal Oxygen Requirement during Positive Pressure Therapy for Sleep Apnea and Medical Comorbidities.
abstract: Home-based management of sleep-disordered breathing (SDB) generally excludes patients with significant medical comorbidities, but such an approach lacks scientific evidence. The current study examined whether significant medical comorbidities are associated with persistent hypoxia that requires unanticipated nocturnal O2supplementation to positive airway pressure (PAP) therapy. Conceivably, in such patients, home-based management of SDB may not detect or therefore adequately treat persistent hypoxia.
  
  
  
  In this retrospective study of 200 patients undergoing laboratory-based polysomnography, we ascertained significant medical comorbidities (chronic obstructive pulmonary disease, congestive heart failure, and morbid obesity) and their association with the need for unanticipated O2supplementation to PAP therapy. Postural oxygen (SpO2) desaturations between upright and reclining positions were determined during calm wakefulness.
  
  
  
  Postural change in SpO2during calm wakefulness was greater in patients who eventually needed nocturnal O2supplementation to PAP therapy than those needing PAP therapy alone (p < 0.0001). The presence of chronic obstructive pulmonary disease (odds ratio [OR] 6.0; 95% confidence interval [CI]; 2.1, 17.5; p = 0.001), morbid obesity (OR 3.6; 95% CI 1.9, 7.0; p < 0.0001), and age older than 50 y (OR 2.8; 95% CI 1.3, 5.9; p = 0.007) but not heart failure were associated with unanticipated need for nocturnal O2supplementation. A clinical prediction rule of less than two determinants (age older than 50 y, morbid obesity, chronic obstructive pulmonary disease, and postural SpO2desaturation greater than 5%) had excellent negative predictive value (0.92; 95% CI 0.85, 0.96) and likelihood ratio of negative test (0.08; 95% CI 0.04, 0.16).
  
  
  
  Medical comorbidities can predict persistent hypoxia that requires unanticipated O2supplementation to PAP therapy. Such findings justify the use of medical comorbidities to exclude home management of SDB.
  
  
  
  A commentary on this article appears in this issue on page 7.
authors.affiliation: Center for Sleep Disorders and Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, University of Arizona, Tucson, AZ.|Department of Medicine, University of Arizona.
authors.forename: Safal
authors.initials: S
authors.lastname: Shetty
authors.affiliation: Center for Sleep Disorders and Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, University of Arizona, Tucson, AZ.|Department of Medicine, University of Arizona.
authors.forename: Aaron
authors.initials: A
authors.lastname: Fernandes
authors.affiliation: Center for Sleep Disorders and Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, University of Arizona, Tucson, AZ.|Department of Medicine, University of Arizona.
authors.forename: Sarah
authors.initials: S
authors.lastname: Patel
authors.affiliation: Arizona Respiratory Center and Department of Pediatrics, University of Arizona.
authors.forename: Daniel
authors.initials: D
authors.lastname: Combs
authors.affiliation: Department of Psychiatry, University of Arizona.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Grandner
authors.affiliation: Center for Sleep Disorders and Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, University of Arizona, Tucson, AZ.|Department of Medicine, University of Arizona.|UAHS Center for Sleep and Circadian Sciences, University of Arizona.
authors.forename: Sairam
authors.initials: S
authors.lastname: Parthasarathy
mesh_terms: D016022:Case-Control Studies; D015897:Comorbidity; D045422:Continuous Positive Airway Pressure / Q000379:methods*; D005260:Female; D006333:Heart Failure / Q000150:complications*; D006801:Humans; D000860:Hypoxia / Q000150:complications* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000150:complications*; D010102:Oxygen Inhalation Therapy; D017286:Polysomnography; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications*; D012189:Retrospective Studies; D012891:Sleep Apnea Syndromes / Q000150:complications* / Q000628:therapy
keywords: clinical prediction rule; home sleep apnea testing; obstructive sleep apnea; oxygen; portable testing; positive airway pressure therapy