title: Is nitrous oxide use appropriate in neurosurgical and neurologically at-risk patients?
abstract: OBJECTIVE
  To address controversial issues surrounding the use of nitrous oxide as a component of anesthesia in neurosurgical and neurologically at-risk patients.
  
  
  RESULTS
  Nitrous oxide has been used as a component of general anesthesia for over 160 years and has contributed to countless apparently uneventful anesthetics in neurologically at-risk patients. Avoidance of nitrous oxide in specific circumstances, such as pre-existing pneumocephalus, during acute venous air embolism, and in patients with disorders of folate metabolism, is warranted. However, various controversies exist regarding the use of this drug in the general neurosurgical population. Specifically, some suggest a possible association between nitrous oxide and the postoperative development of tension pneumocephalus despite lack of data to support this notion. Additionally, data describing alterations of cerebral hemodynamics and metabolism and exacerbation of ischemic neurologic injury by nitrous oxide are inconsistent. Recent data derived from humans having cerebral aneurysm clipping failed to show any long-term adverse effect from the use of nitrous oxide on gross neurologic or cognitive function.
  
  
  CONCLUSIONS
  Except in a few specific circumstances, there exists no conclusive evidence to support the dogmatic avoidance of nitrous oxide in neurosurgical patients.
authors.affiliation: Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA. pasternak.jeffrey@mayo.edu
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Pasternak
authors.forename: William L
authors.initials: WL
authors.lastname: Lanier
mesh_terms: D000768:Anesthesia, General; D018685:Anesthetics, Inhalation / Q000009:adverse effects; D001810:Blood Volume / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology; D004569:Electroencephalography; D006801:Humans; D008660:Metabolism / Q000502:physiology; D016343:Monitoring, Intraoperative; D009422:Nervous System Diseases / Q000150:complications*; D019635:Neurosurgical Procedures / Q000379:methods*; D009609:Nitrous Oxide / Q000009:adverse effects; D012306:Risk; D014805:Vitamin B 12 / Q000502:physiology
chemical_list: D018685:Anesthetics, Inhalation; D009609:Nitrous Oxide; D014805:Vitamin B 12