title: Sevoflurane degradation product concentrations with soda lime during prolonged anesthesia.
abstract: OBJECTIVE
  To evaluate the decomposition of sevoflurane in soda lime during prolonged sevoflurane anesthesia in humans. To evaluate for evidence of renal or hepatotoxicity as a result of exposure to these sevoflurane degradation compounds.
  
  
  METHODS
  Prospective evaluation in healthy volunteers.
  
  
  METHODS
  Clinical research unit and postanesthesia care unit of a university hospital.
  
  
  METHODS
  Six healthy male volunteers.
  
  
  METHODS
  Subjects were anesthetized with sevoflurane 1 to 1.2 minimum alveolar concentration for greater than 9 hours with a semiclosed circuit anesthetic technique (5-liter total flow) with fresh soda lime as the absorbent.
  
  
  RESULTS
  Laboratory tests of renal and hepatic function were performed before anesthesia and 1 and 5 days after anesthesia. During sevoflurane anesthesia, inhalation and exhalation circuit limb gas samples were obtained for degradation compound analysis. Only one degradation product, fluoromethyl-2,2-difluoro-1-(trifluoromethyl) vinyl ether (compound A), was detected. Inhalation concentration was maximal (7.6 +/- 1.0 ppm) at 2 hours and did not increase further after this time point. There were no differences in preanesthesia and postanesthesia tests of hepatic and renal function.
  
  
  CONCLUSIONS
  Levels of the degradation compound (compound A) produced in semiclosed circuit sevoflurane anesthesia with soda lime are well below potential toxic levels and thus appear safe. When sevoflurane is administered under these conditions for prolonged anesthesia, concentrations of compound A do not continue to increase throughout anesthesia.
authors.affiliation: Department of Anesthesiology, University of Arizona Health Sciences Center, Tucson 85724.
authors.forename: E J
authors.initials: EJ
authors.lastname: Frink
authors.forename: R J
authors.initials: RJ
authors.lastname: Isner
authors.forename: T P
authors.initials: TP
authors.lastname: Malan
authors.forename: S E
authors.initials: SE
authors.lastname: Morgan
authors.forename: E A
authors.initials: EA
authors.lastname: Brown
authors.forename: B R
authors.initials: BR
authors.lastname: Brown
mesh_terms: D000327:Adsorption; D000764:Anesthesia, Closed-Circuit; D000777:Anesthetics / Q000008:administration & dosage / Q000737:chemistry*; D001219:Aspartate Aminotransferases / Q000097:blood; D017610:Calcium Compounds; D004987:Ethers / Q000008:administration & dosage / Q000032:analysis* / Q000737:chemistry* / Q000494:pharmacology; D006801:Humans; D006845:Hydrocarbons, Fluorinated / Q000032:analysis* / Q000494:pharmacology; D007668:Kidney / Q000187:drug effects; D008099:Liver / Q000187:drug effects; D008297:Male; D008738:Methyl Ethers; D009330:Nebulizers and Vaporizers; D010087:Oxides; D011446:Prospective Studies; D000077149:Sevoflurane; D012972:Sodium Hydroxide / Q000737:chemistry*; D013990:Tidal Volume; D013997:Time Factors
chemical_list: D000777:Anesthetics; D017610:Calcium Compounds; D004987:Ethers; D006845:Hydrocarbons, Fluorinated; D008738:Methyl Ethers; D010087:Oxides; C078747:fluoromethyl 2-methoxy-2-fluoro-1-(trifluoromethyl)vinyl ether; D000077149:Sevoflurane; C004569:soda lime; D012972:Sodium Hydroxide; C078745:fluoromethyl 2-methoxy-2,2-difluoro-1-(trifluoromethyl)ethyl ether; C078742:fluoromethyl 2,2-difluoro-1-(trifluoromethyl)vinyl ether; D001219:Aspartate Aminotransferases