title: Nitrous oxide and serious morbidity and mortality in the POISE trial.
abstract: BACKGROUND
  In this post hoc subanalysis of the Perioperative Ischemic Evaluation (POISE) trial, we sought to determine whether nitrous oxide was associated with the primary composite outcome of cardiovascular death, nonfatal myocardial infarction (MI), and nonfatal cardiac arrest within 30 days of randomization.
  
  
  METHODS
  The POISE trial of perioperative β-blockade was undertaken in 8351 patients. Nitrous oxide anesthesia was defined as the coadministration of nitrous oxide in patients receiving general anesthesia, with or without additional neuraxial blockade or peripheral nerve blockade. Logistic regression, with inverse probability weighting using estimated propensity scores, was used to determine the association of nitrous oxide with the primary outcome, MI, stroke, death, and clinically significant hypotension.
  
  
  RESULTS
  Nitrous oxide was administered to 1489 (29%) of the 5133 patients included in this analysis. Nitrous oxide had no significant effect on the risk of the primary outcome (112 [7.5%] vs 248 [6.9%]; odds ratio [OR], 1.08; 95% confidence interval [CI], 0.82-1.44; 99% CI, 0.75-1.57; P = 0.58), MI (89 [6.0] vs 204 [5.6]; OR, 0.99; 95% CI, 0.75-1.31; 99% CI, 0.69-1.42; P = 0.94), stroke (6 [0.4%] vs 28 [0.8%]; OR, 0.85; 95% CI, 0.26-2.82; 99% CI, 0.17-4.11; P = 0.79), death (40 [2.7%] vs 100 [2.8%]; OR, 1.04; 95% CI, 0.6-1.81; 99% CI, 0.51-2.15; P = 0.88) or clinically significant hypotension (219 [14.7%] vs 544 [15.0%]; OR, 0.92; 95% CI, 0.74-1.15; 99% CI, 0.70-1.23; P = 0.48).
  
  
  CONCLUSIONS
  In this post hoc subanalysis, nitrous oxide was not associated with an increased risk of adverse outcomes in the POISE trial patients. This analysis was limited by the observational nature of the data and the lack of information on the concentration and duration of nitrous oxide administration. Further randomized controlled trial evidence is required.
authors: From the Department of Anaesthesia and Pain Management, Royal Melbourne Hospital, Melbourne; Department of Pharmacology, University of Melbourne, Melbourne; Department of Anaesthesia and Perioperative Medicine, Alfred Hospital, Melbourne; Academic Board of Anaesthesia and Perioperative Medicine, Monash University, Melbourne, Australia; Departments of Medicine and Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada; Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia; Population Health Research Institute, McMaster University, Hamilton, Ontario, Canada; School of Population Health, University of Melbourne, Melbourne, Australia; Fu Wai Cardiovascular Hospital, CAMS, Beijing, Peoples Republic of China; Nuffield Division of Anaesthetics, Oxford University, Oxford, United Kingdom; Nueva Granada Military University, Bogota; Department of Anaesthesia, Resuscitation and Pain Management, Central Military Hospital, Bogota, Colombia; Department of Anesthesiology, The Ottawa Hospital, Ottawa, Ontario; Department of Anesthesia, McMaster University, Hamilton Health Sciences, Hamilton, Ontario, Canada; School of Medicine and Pharmacology, University of Western Australia, Perth; Department of Anaesthesia and Pain Medicine, King Edward Memorial Hospital for Women, Perth, Australia; Department of Anesthesia and Perioperative Medicine, Royal Columbian Hospital, New Westminster, British Columbia; Department of Anesthesiology, the University of British Columbia, Vancouver, British Columbia; Department of Anesthesia, Perioperative Medicine, University of Western Ontario, London, Ontario, Canada; Department of Anaesthesia, Department of Surgery, Austin Hospital and University of Melbourne, Melbourne, Australia; Nuffield Department of Anaesthetics, Oxford University, Oxford, United Kingdom; and Department of Anesthesia, University of Ottawa, Ottawa, Ontario, Canada.
authors: Kate
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authors: Paul
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authors: Paech
authors: Richard N
authors: RN
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authors: PT
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authors: Badner
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mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000769:Anesthesia, Inhalation / Q000009:adverse effects; D018685:Anesthetics, Inhalation / Q000009:adverse effects*; D016001:Confidence Intervals; D003627:Data Interpretation, Statistical; D004311:Double-Blind Method; D004363:Drug Utilization; D005260:Female; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000627:therapeutic use; D007431:Intraoperative Complications / Q000453:epidemiology* / Q000401:mortality*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology; D009609:Nitrous Oxide / Q000009:adverse effects*; D016017:Odds Ratio; D059035:Perioperative Period / Q000401:mortality*; D011183:Postoperative Complications / Q000453:epidemiology* / Q000401:mortality*; D011229:Preanesthetic Medication; D057216:Propensity Score; D012737:Sex Factors; D016896:Treatment Outcome
chemical_list: D018685:Anesthetics, Inhalation; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D009609:Nitrous Oxide