title: Perioperative supplemental oxygen in colorectal patients: a meta-analysis.
abstract: BACKGROUND
  Perioperative supplemental oxygen has been proposed to decrease the incidence of surgical site infection (SSI) in colorectal surgery. A number of randomized controlled trials (RCTs) have been reported with inconsistent results. In addition, relevant clinical outcomes other than SSIs have been collected in these studies and have been equivocal. A meta-analysis of RCTs was performed to elucidate the effects of perioperative supplemental oxygen in colorectal surgery on SSI incidence, mortality, ICU admission, and length of stay.
  
  
  METHODS
  A literature search of MEDLINE, PubMed, EMBASE, the Cochrane Library, and the Cochrane Clinical Trials Registry was performed in duplicate. In addition, bibliographic searches were performed, and experts were contacted for unpublished data. RCTs involving colorectal patients that included perioperative supplemental oxygen as a treatment arm and defined SSI as an outcome were included.
  
  
  RESULTS
  Five studies met inclusion criteria. Using a random-effects model, perioperative supplemental oxygen did not significantly reduce SSIs (OR = 0.69, 95% CI [0.43, 1.10], P = 0.12). However, a significant mortality benefit was observed (OR = 0.18, 95% CI [0.05, 0.69], P = 0.01). There was no significant difference in the rate of ICU admission or length of stay. Tests of heterogeneity were performed, and significant heterogeneity was only present with respect to length of stay.
  
  
  CONCLUSIONS
  Perioperative supplemental oxygen in colorectal surgery does not significantly reduce SSI. However, supplemental oxygen appears to confer a mortality benefit, a previously unreported finding. Further RCTs are required to confirm these conclusions.
authors.affiliation: Department of Surgery, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Mantaj S
authors.initials: MS
authors.lastname: Brar
authors.forename: Savtaj S
authors.initials: SS
authors.lastname: Brar
authors.forename: Elijah
authors.initials: E
authors.lastname: Dixon
mesh_terms: D003108:Colonic Diseases / Q000401:mortality / Q000601:surgery*; D006801:Humans; D015994:Incidence; D010100:Oxygen / Q000008:administration & dosage*; D012002:Rectal Diseases / Q000401:mortality / Q000601:surgery*; D013530:Surgical Wound Infection / Q000401:mortality / Q000517:prevention & control*
chemical_list: D010100:Oxygen