title: Effects of nitrous oxide sedation on resting electroencephalogram topography.
abstract: OBJECTIVE
  To quantify the effects of nitrous oxide (N(2)O) gas on electroencephalogram (EEG) topography in healthy male participants.
  
  
  METHODS
  Healthy male participants were administered 20% (n=8) or 40% (n=8) N(2)O while having high-density (modified 10-20) noise minimized EEG recordings.
  
  
  RESULTS
  Nitrous oxide was found to produce clear reductions in resting total power, particularly at frontal-vertex sites. These reductions were found to principally reflect reductions in band-limited delta power. Following the termination of N(2)O inhalation, during N(2)O washout, selective increases in frontal theta power were observed that increased above baseline values.
  
  
  CONCLUSIONS
  Nitrous oxide does not produce the classical anteriorization of slow wave activity typically seen during anesthetic induction. Instead N(2)O reduces frontal slow wave (delta) activity, which during gas washout produces a withdrawal response of enhanced frontal slow wave (theta) activity.
  
  
  CONCLUSIONS
  Attempts to characterize a unitary mechanism of loss of consciousness during anesthesia on the basis of the topographic electroencephalographic changes is challenged by the distinct EEG effects that N(2)O has when compared to other well known anesthetic agents that include propofol and sevoflurane.
authors.affiliation: Department of Neurology and Neurological Sciences, School of Medicine, Stanford University, Stanford, CA 94305-5235, United States. blfoster@stanford.edu
authors.forename: Brett L
authors.initials: BL
authors.lastname: Foster
authors.forename: David T J
authors.initials: DT
authors.lastname: Liley
mesh_terms: D000328:Adult; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D001931:Brain Mapping; D003700:Delta Rhythm / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004569:Electroencephalography / Q000187:drug effects*; D005625:Frontal Lobe / Q000187:drug effects / Q000502:physiology; D006801:Humans; D008297:Male; D009609:Nitrous Oxide / Q000494:pharmacology*; D012146:Rest / Q000502:physiology*; D013826:Theta Rhythm / Q000187:drug effects / Q000502:physiology
chemical_list: D018685:Anesthetics, Inhalation; D009609:Nitrous Oxide