title: [Supplemental oxygen for the prevention of postoperative nausea and vomiting: a meta-analysis of randomized clinical trials].
abstract: OBJECTIVE
  Despite the development of antiemetic drugs, the incidence of postoperative nausea and vomiting remains between 20% and 30%. This meta-analysis examines the hypothesis that perioperative administration of supplemental oxygen reduces the incidence of these complications.
  
  
  METHODS
  We performed a systematic search of the literature through MEDLINE, EMBASE, the Cochrane Library, reference lists, and a manual search, with no language restrictions, up to September 2007 to identify randomized clinical trials evaluating the effect o f supplemental oxygen on postoperative nausea and vomiting. The data were extracted and analyzed using the RevMan program, version 4.2.9 (Cochrane Collaboration, Oxford, UK).
  
  
  RESULTS
  The study included 9 randomized clinical trials with a total of 1661 enrolled patients (824 assigned to the group with a higher oxygen concentration and 837 assigned to the group with a lower oxygen concentration). Perioperative supplemental oxygen has no effect on the incidence of nausea (relative risk [RR], 0.94; 95% confidence interval [CI], 0.82 to 1.08), postoperative nausea and/or vomiting (RR, 0.93; 95% CI, 0.74 to 1.17), or the need for rescue antiemetic drugs (RR, 0.90; 95% CI, 0.70 to 1.15). The incidence of vomiting, however, is reduced (RR, 0.77; 95% CI, 0.62 to 0.97). Significant differences were not found in the incidence of atelectasis (RR, 1.23; 95% CI, 0.50 to 3.00) or postoperative PaCO2 (weighted mean difference, -4.0; 95% CI, -12.3 to 4.3).
  
  
  CONCLUSIONS
  Supplemental oxygen reduces the incidence of postoperative vomiting. Administration of supplemental oxygen could be an effective method of reducing postoperative vomiting but does not replace current indications for pharmacologic prophylaxis.
authors.affiliation: Unidad de Anestesiología y Reanimación, Departamento de Cirugía, Facultad de Medicina, Universidad Nacional de Colombia. darinconv@unal.edu.co
authors.forename: D A
authors.initials: DA
authors.lastname: Rincón
authors.forename: J F
authors.initials: JF
authors.lastname: Valero
mesh_terms: D000328:Adult; D000932:Antiemetics / Q000627:therapeutic use; D003131:Combined Modality Therapy; D004305:Dose-Response Relationship, Drug; D006801:Humans; D015994:Incidence; D007430:Intraoperative Care; D009325:Nausea / Q000453:epidemiology / Q000517:prevention & control*; D010100:Oxygen / Q000008:administration & dosage / Q000097:blood; D010102:Oxygen Inhalation Therapy; D011182:Postoperative Care; D011183:Postoperative Complications / Q000453:epidemiology / Q000517:prevention & control*; D001261:Pulmonary Atelectasis / Q000517:prevention & control; D016032:Randomized Controlled Trials as Topic / Q000706:statistics & numerical data; D012306:Risk; D013514:Surgical Procedures, Operative; D014839:Vomiting / Q000453:epidemiology / Q000517:prevention & control*
chemical_list: D000932:Antiemetics; D010100:Oxygen