title: Effects of supplemental oxygen and dexamethasone on surgical site infection: a factorial randomized trial‡.
abstract: BACKGROUND
  Tissue oxygenation is a strong predictor of surgical site infection. Improving tissue oxygenation should thus reduce wound infection risk. Supplemental inspired oxygen can improve tissue oxygenation, but whether it reduces infection risk remains controversial. Low-dose dexamethasone is often given to reduce the risk of postoperative nausea and vomiting, but steroid-induced immunosuppression can increase infection risk. We therefore tested the hypotheses that supplemental perioperative oxygen reduces infection risk and that dexamethasone increases it.
  
  
  METHODS
  Using a factorial design, patients having colorectal resections expected to last ≥2 h were randomly assigned to 30% (n=270) or 80% (n=285) inspired oxygen during and for 1 h after surgery, and to 4 mg intraoperative dexamethasone (n=283) or placebo (n=272). Physicians blinded to group assignments evaluated wounds postoperatively, using US Centers for Disease Control criteria.
  
  
  RESULTS
  Subject and surgical characteristics were similar among study groups. Surgical site infection incidence was similar among groups: 30% oxygen 15.6%, 80% oxygen 15.8% (P=1.00); dexamethasone 15.9%, placebo 15.4%, (P=0.91).
  
  
  CONCLUSIONS
  Supplemental oxygen did not reduce surgical site infection risk. The preponderance of clinical evidence suggests that administration of 80% supplemental inspired oxygen does not reduce infection risk. We did not observe an increased risk of surgical site infection with the use of a single low dose of dexamethasone, indicating that it can be used for nausea and vomiting prophylaxis without promoting wound infections.
  
  
  BACKGROUND
  ClinicalTrials.gov number: NCT00273377.
authors.affiliation: Department of Outcomes Research, Cleveland Clinic, Cleveland, OH, USA.
authors.forename: A
authors.initials: A
authors.lastname: Kurz
authors.affiliation: Department of Anaesthesia, Medical University of Vienna, Vienna Medical University, Vienna, Austria.
authors.forename: E
authors.initials: E
authors.lastname: Fleischmann
authors.affiliation: Department of Outcomes Research, Cleveland Clinic, Cleveland, OH, USA ds@or.org.
authors.forename: D I
authors.initials: DI
authors.lastname: Sessler
authors.affiliation: School of Medicine and Medical Science, University College Dublin and Mater Misericordiae University Hospital, Dublin, Ireland.
authors.forename: D J
authors.initials: DJ
authors.lastname: Buggy
authors.affiliation: Sagemedic, Inc., Larkspur, CA, USA.
authors.forename: C
authors.initials: C
authors.lastname: Apfel
authors.affiliation: Department of Anaesthesiology and Perioperative Medicine, University of Louisville, Louisville, KY, USA.
authors.forename: O
authors.initials: O
authors.lastname: Akça
mesh_terms: D000932:Antiemetics / Q000008:administration & dosage*; D003107:Colorectal Surgery; D003907:Dexamethasone / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000008:administration & dosage*; D011183:Postoperative Complications / Q000453:epidemiology*; D013530:Surgical Wound Infection / Q000453:epidemiology*
chemical_list: D000932:Antiemetics; D003907:Dexamethasone; D010100:Oxygen
keywords: anaesthesia; oxygen; postoperative infection; random allocation; steroids, dexamethasone; surgery, complications, infection