title: Compound A and carbon monoxide production from sevoflurane and seven different types of carbon dioxide absorbent in a patient model.
abstract: BACKGROUND
  The degradation of sevoflurane can lead to the production of compound A (CA) and carbon monoxide (CO) and an increase in temperature of the absorbent. CA is known to be nephrotoxic in rats. These reactions depend on the strong base and water contents of the carbon dioxide absorbent used. The purpose of this study was to measure the maximum amounts of CA and CO produced, and the temperature increase, for seven different carbon dioxide absorbents for sevoflurane containing different contents of strong bases.
  
  
  METHODS
  Seven absorbents [some free of strong bases (f)] were employed in hydrated (h) and completely desiccated (d) conditions in a patient model, using a circle anesthesia system connected to an artificial lung. Low-flow anesthesia with an oxygen-nitrous oxide mixture was maintained using 0.8% sevoflurane. For the quantification of CA and CO, a portable gas chromatograph was used. The temperature was measured inside the absorbent.
  
  
  RESULTS
  In consecutive order of CA-producing potency, Amsorb(f)(d), Drägersorb(h), Medisorb(h), lithium hydroxide(f)(d), Drägersorb(d), Medisorb(d), Spherasorb(h) and Spherasorb(d) produced small amounts of CA. Loflosorb and Superia, which are free of strong bases, did not produce any CA or CO in hydrated or desiccated conditions. Only desiccated Drägersorb, Medisorb and Spherasorb demonstrated small amounts of CO accompanied by a significant temperature increase.
  
  
  CONCLUSIONS
  In this patient model, we demonstrated that different types of absorbent produced small amounts of CA and CO or none at all. No relationship could be established between temperature and CA concentration.
authors.affiliation: Department of Anesthesiology and Intensive Care, Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital, Amsterdam, the Netherlands. c.keijzer@nki.nl
authors.forename: C
authors.initials: C
authors.lastname: Keijzer
authors.forename: R S G M
authors.initials: RS
authors.lastname: Perez
authors.forename: J J
authors.initials: JJ
authors.lastname: de Lange
mesh_terms: D000042:Absorption; D000764:Anesthesia, Closed-Circuit; D018685:Anesthetics, Inhalation / Q000737:chemistry*; D002245:Carbon Dioxide / Q000737:chemistry; D002248:Carbon Monoxide / Q000737:chemistry*; D002849:Chromatography, Gas; D004987:Ethers / Q000737:chemistry*; D006845:Hydrocarbons, Fluorinated / Q000737:chemistry*; D008738:Methyl Ethers / Q000737:chemistry*; D008954:Models, Biological; D000077149:Sevoflurane; D013696:Temperature
chemical_list: D018685:Anesthetics, Inhalation; D004987:Ethers; D006845:Hydrocarbons, Fluorinated; D008738:Methyl Ethers; D002245:Carbon Dioxide; D000077149:Sevoflurane; C078742:fluoromethyl 2,2-difluoro-1-(trifluoromethyl)vinyl ether; D002248:Carbon Monoxide