title: The perioperative use of nitrous oxide: renaissance of an old gas or funeral of an ancient relict?
abstract: OBJECTIVE
  Conflicting reports about adverse events following nitrous oxide (N(2)O) application have spurred a discussion whether N(2)O should be abandoned from clinical practice. Concurrently, N(2)O is increasingly used as a single anesthetic agent in medical procedures. This article reviews and discusses reports about the present use of N(2)O.
  
  
  RESULTS
  Multiple publications demonstrate an increasing use of N(2)O as a procedural analgesic and sedative. Results from the Evaluation of Nitrous Oxide in the Gas Mixture for Anesthesia trial have been contrasted by recent studies reporting no increased risk for perioperative complications, particularly related to the cardiovascular and cerebrovascular system. Recent studies show that electroencephalogram-based anesthesia depth monitoring is not compatible with the use of N(2)O because of its distinct influence on electroencephalogram wave patterns. The clinical relevance of the proposed neurotoxicity, immunosuppression and influence on methionine metabolism remains unclear. Recently, its acute and long-term analgesic potency has been proven. Occupational exposure might pose a relevant health hazard.
  
  
  CONCLUSIONS
  Based on the present literature, abolishment of N(2)O is controversial. When avoided in patients at risk for adverse events, N(2)O is still a valuable supplement to general anesthesia and a potent procedural analgesic drug. In the latter, its use by nonanesthesiologists should be discouraged.
authors: Department of Anesthesiology and Critical Care Medicine, University Medical Center, Freiburg, Germany. nils.schallner@uniklinikfreiburg.de
authors: Nils
authors: N
authors: Schallner
authors: Ulrich
authors: U
authors: Goebel
mesh_terms: D000700:Analgesics; D000776:Anesthesiology; D018685:Anesthetics, Inhalation / Q000009:adverse effects / Q000494:pharmacology; D014151:Anti-Anxiety Agents; D006710:Homocysteine / Q000378:metabolism; D006801:Humans; D007107:Immune System / Q000187:drug effects; D058926:Intraoperative Awareness; D008715:Methionine / Q000378:metabolism; D009609:Nitrous Oxide / Q000009:adverse effects / Q000494:pharmacology; D016273:Occupational Exposure / Q000009:adverse effects; D019990:Perioperative Care
chemical_list: D000700:Analgesics; D018685:Anesthetics, Inhalation; D014151:Anti-Anxiety Agents; D006710:Homocysteine; D008715:Methionine; D009609:Nitrous Oxide