title: Postoperative sleep-disordered breathing in patients without preoperative sleep apnea.
abstract: BACKGROUND
  Recently published data show that postoperative apnea-hypopnea index (AHI) is significantly increased in some patients without preoperative sleep apnea. These patients may be at risk of developing perioperative adverse events related to sleep-disordered breathing (SDB). The objective of this study was to investigate the incidence and predictors of postoperative moderate-to-severe SDB (AHI > 15 events/h) in patients without sleep apnea preoperatively.
  
  
  METHODS
  In a prospective observational fashion, patients were invited to undergo sleep studies with a portable device (Embletta X100) preoperatively at home and postoperatively on the first and third night after surgery in the hospital or at home. The primary outcome was the incidence of postoperative moderate-to-severe SDB (AHI > 15 events/h) in non-sleep apnea patients (preoperative AHI ≤ 5 events/h). Logistic regression was used to evaluate the association of clinical factors and preoperative sleep parameters with the occurrence of postoperative moderate-to-severe SDB.
  
  
  RESULTS
  A total of 120 non-sleep apnea patients completed the study, of which 31 (25.8% [95% confidence interval: 18.3%-34.6%]) patients were found to have AHI > 15 events/h on postoperative night 1 and/or postoperative night 3 (postoperative SDB group), and 89 (74%) patients had an AHI ≤ 15 events/h on both postoperative night 1 and 3 (postoperative non-SDB group). The patients in the postoperative SDB group were older (60 ± 13 vs 53 ± 12 years, P = 0.008) with more smokers (32.3% vs 15.7%, P = 0.048) and had a greater increase in the obstructive apnea index (adjusted P = 0.0003), central apnea index (adjusted P = 0.0012), and hypopnea index (adjusted P = 0.0004). Multivariate logistic regression analysis found that age and preoperative respiratory disturbance index (RDI) were significantly associated with the occurrence of postoperative moderate-to-severe SDB, P = 0.018 and P = 0.006, respectively. The sensitivity privilege cutoff of RDI at 4.9 events/h identified 70.2% to 96.4%patients developing postoperative moderate-to-severe SDB.
  
  
  CONCLUSIONS
  At least 18.3% of non-sleep apnea patients developed moderate-to-severe SDB after surgery. Age and preoperative RDI were associated with the occurrence of postoperative moderate-to-severe SDB.
authors.affiliation: From the *Department of Anesthesia, Toronto Western Hospital, University Health Network and Women's College Hospital, University of Toronto, Toronto, Ontario, Canada; †Anesthesia and Psychiatry and Sleep Research Unit, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada; ‡Section of Pulmonary and Critical Care Medicine, University of Chicago Pritzker School of Medicine, Chicago, Illinois; and §Psychiatry and Sleep Research Unit, Department of Psychiatry, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada.
authors.forename: Frances
authors.initials: F
authors.lastname: Chung
authors.forename: Pu
authors.initials: P
authors.lastname: Liao
authors.forename: Yiliang
authors.initials: Y
authors.lastname: Yang
authors.forename: Maged
authors.initials: M
authors.lastname: Andrawes
authors.forename: Weimin
authors.initials: W
authors.lastname: Kang
authors.forename: Babak
authors.initials: B
authors.lastname: Mokhlesi
authors.forename: Colin M
authors.initials: CM
authors.lastname: Shapiro
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008168:Lung / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009864:Ontario / Q000453:epidemiology; D011446:Prospective Studies; D012119:Respiration; D012307:Risk Factors; D012720:Severity of Illness Index; D012890:Sleep; D012891:Sleep Apnea Syndromes / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology; D013514:Surgical Procedures, Operative / Q000009:adverse effects*; D013997:Time Factors; D016896:Treatment Outcome