Nitrous oxide and long-term morbidity and mortality in the ENIGMA trial

Nitrous oxide and long-term morbidity and mortality in the ENIGMA trial Go to main page content home current query previous queries CME subscribe ONLINE using send to (A) and (A) activate my account search go advanced search? user name password characters in N2O emissions and long-term morbidity and mortality in the ENIGMA trial Kate Leslie, MBBS, MD, MEpi, FANZCA *, Paul s. Myles, MBBS, MD, MPH, FANZCA, FCARSCI, FRCA ?, Matthew t. v. Chan, MBBSFANZCA ?, Andrew Forbes, MSc, PhD, Michael j. Paech, MBBS, DM, DRCOG, FRCA, FANZCA, FFPMANZCA, FRANZCOG (She) ?, Philip Peyton, MBBS, MD, FANZCA, Brendan p. Silbert, MBBS, FANZCA # and Elizabeth Williamson, PhD **

Authors' affiliations are listed at the end of the article. Address correspondence to Kate Leslie, MBBS, MD, MEpi, FANZCA, Parkville, Victoria, 3050, Australia. Address e-mail to kate.leslie{at}mh.org.au. Abstract BACKGROUND: There is a plausible pathophysiologic rationale for increased long-term cardiovascular morbidity and mortality in patients receiving significant exposure to nitrous oxide. However, this relationship has not been established clinically. The ENIGMA trial randomized 2050 patients having noncardiac surgery lasting more than 2 hours to nitrous oxide–based or nitrous oxide–free anesthesia. We conducted a follow-up study of the ENIGMA patients to evaluate the risk of cardiovascular events in the longer term. METHODS: The trial case report forms and medical records of all study patients were reviewed. The date and cause of death and occurrence of myocardial infarction or stroke were recorded. A telephone interview was then conducted with all surviving patients. The primary endpoint of the study was survival. RESULTS: The median follow-up time was 3.5 (range: 0 to 5.7) years. Three hundred eighty patients (19%) had died since the index surgery, 91 (4.5%) were recorded as having myocardial infarction, and 44 (2.2%) had a stroke during the entire follow-up period. Nitrous oxide did not significantly increase the risk of death [hazard ratio = 0.98 (95% confidence interval, CI: 0.80 to 1.20; P = 0.82)]. The adjusted odds ratio for myocardial infarction in patients administered nitrous oxide was 1.59 (95% CI: 1.01 to 2.51; P = 0.04) and for stroke was 1.01 (95% CI: 0.55 to 1.87; P = 0.97). CONCLUSIONS: The administration of nitrous oxide was associated with increased long-term risk of myocardial infarction, but not of death or stroke in patients enrolled in the ENIGMA trial. The exact relationship between nitrous oxide administration and serious long-term adverse outcomes will require confirmation by an appropriately designed large randomized controlled trial. Footnotes This study was supported by a project grant from the Australian and New Zealand College of Anaesthetists and a direct grant for research from the Chinese University of Hong Kong (project #2041315). The ENIGMA Trial was funded by the National Health and Medical Research Council of Australia (236956). Accepted August 5, 2010. Copyright ? 2011 International Anesthesia Research Society ? Previous | Next Article ?Table of Contents This Article Published online before print September 22, 2010, doi: 10.1213/?ANE.0b013e3181f7e2c4 A & A February 2011 vol. 112 no. 2 387-393 ? Abstract Full Text Full Text (PDF) Classifications Patient Safety Services Email this article to a colleague Alert me when this article is cited Alert me if a correction is posted Similar articles in this journal Similar articles in PubMed Download to citation manager Request Permissions Citing Articles Load citing article information Google Scholar Articles by Leslie, K. Articles by Williamson, E. Search for related content PubMed PubMed citation Articles by Leslie, K. Articles by Williamson, E. Related Content Cardiovascular Complications Outcomes Patient Safety Pharmacology Load related web page information Current Issue July 2011, 113 (1) Alert me to new issues of A & A Join the IARS About A&A Mission Editorial Board For Authors For Reviewers Cover Art Sign up Sign up for eTOCs Sign up for RSS feeds Browse by Topic Permissions and Copyright Press Room OpenAnesthesia Advertise in A&A Career Center Most Read Special Article: 2010 Anesthesia & Analgesia Guide for Authors: 2009-2010 Editorial Board, Anesthesia & Analgesia Hand Contamination of Anesthesia Providers Is an Important Risk Factor for Intraoperative Bacterial Transmission Postoperative Sore Throat: More Answers Than Questions Nitrous Oxide and Long-Term Morbidity and Mortality in the ENIGMA Trial Surgical Site Infections and the Anesthesia Professionals' Microbiome: We've All Been Slimed! Now What Are We Going to Do About It? ? View all Most Read articles Cited ASE/SCA Guidelines for Performing a Comprehensive Intraoperative Multiplane Transesophageal Echocardiography Examination: Recommendations of the American Society of Echocardiography Council for Intraoperative Echocardiography and the Society of Cardiovascular Anesthesiologists Task Force for Certification in Perioperative Transesophageal Echocardiography The comparative effects of postoperative analgesic therapies on pulmonary outcome: cumulative meta-analyses of randomized, controlled trials Consensus Guidelines for Managing Postoperative Nausea and Vomiting Cerebral Autoregulation and Flow/Metabolism Coupling during Cardiopulmonary Bypass: The Influence of Paco2 A Postanesthetic Recovery Score ? View all Most Cited articles Copyright ? 2011 by the International Anesthesia Research Society Print ISSN: 0003-2999 Online ISSN: 1526-7598

View the original article here