title: The Effects of Continuous Positive Airway Pressure on Postoperative Outcomes in Obstructive Sleep Apnea Patients Undergoing Surgery: A Systematic Review and Meta-analysis.
abstract: BACKGROUND
  Obstructive sleep apnea (OSA) is a commonly encountered comorbid condition in patients undergoing surgery and is associated with a greater risk of postoperative adverse events. Our objective in this review was to investigate the effectiveness of continuous positive airway pressure (CPAP) in reducing the risk of postoperative adverse events in patients with OSA undergoing surgery, the perioperative Apnea-Hypopnea Index (AHI), and the hospital length of stay (LOS).
  
  
  METHODS
  We performed a systematic search of the literature databases. We reviewed the studies that included the following: (1) adult surgical patients (>18 years old) with information available on OSA; (2) patients using either preoperative and/or postoperative CPAP or no-CPAP; (3) available reports on postoperative adverse events, preoperative and postoperative AHI, and LOS; and (4) all published studies in English including case series.
  
  
  RESULTS
  Six studies that included 904 patients were eligible for the meta-analysis. The meta-analysis for postoperative adverse events was performed in 904 patients (CPAP: n = 471 vs no-CPAP: n = 433; adverse events: 134 vs 133; P = 0.19). There was no significant difference in the postoperative adverse events between the 2 groups. The preoperative baseline AHI without CPAP was reduced significantly with postoperative use of CPAP (preoperative AHI versus postoperative AHI, 37 ± 19 vs 12 ± 16 events per hour, P < 0.001). LOS showed a trend toward significance in the CPAP group versus the no-CPAP group (4.0 ± 4 vs 4.4 ± 8 days, P = 0.05).
  
  
  CONCLUSIONS
  Our review suggests that there was no significant difference in the postoperative adverse events between CPAP and no-CPAP treatment. Patients using CPAP had significantly lower postoperative AHI and a trend toward shorter LOS. There may be potential benefits in the use of CPAP during the perioperative period.
authors.affiliation: From the Department of Anesthesiology, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada; Department of Medicine, Sleep Disorders Center and the Section of Pulmonary and Critical Care, University of Chicago, Chicago, Illinois; Department of Anesthesiology, Toronto Western Hospital, University Health, Toronto, Ontario, Canada; Department of Hospital Medicine and Department of Outcomes Research (Anesthesiology), Cleveland Clinic, Cleveland, Ohio; and Department of Anesthesia, Toronto Western Hospital, Women's College Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Mahesh
authors.initials: M
authors.lastname: Nagappa
authors.forename: Babak
authors.initials: B
authors.lastname: Mokhlesi
authors.forename: Jean
authors.initials: J
authors.lastname: Wong
authors.forename: David T
authors.initials: DT
authors.lastname: Wong
authors.forename: Roop
authors.initials: R
authors.lastname: Kaw
authors.forename: Frances
authors.initials: F
authors.lastname: Chung
mesh_terms: D016009:Chi-Square Distribution; D015897:Comorbidity; D045422:Continuous Positive Airway Pressure; D006801:Humans; D007902:Length of Stay; D016017:Odds Ratio; D011183:Postoperative Complications / Q000453:epidemiology / Q000517:prevention & control; D012307:Risk Factors; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis / Q000453:epidemiology / Q000628:therapy*; D013514:Surgical Procedures, Operative / Q000009:adverse effects; D013997:Time Factors