title: Sevoflurane degradation to compound A in anaesthesia breathing systems.
abstract: Determination of an effective rate constant and activation energy allowed the application of steady-state theory to predict concentrations of compound A from sevoflurane concentrations, fresh gas flow rate, absorbent temperature and amount of absorbent. Studies by eight research groups were compared. Lower concentrations of compound A than predicted were observed at low flow rates, suggesting that its degradation by the absorbent is important in limiting the maximum observed concentrations in closed and low-flow breathing systems. Trial-to-trial and batch-to-batch variations in compound A concentrations were observed in model system tests of commercial and pilot-plant absorbents. Chemical modification of the absorbent with glycerol lowered concentrations of compound A, possibly by formation of a nucleophilic addition product. An ideal chemical scavenger would remain stable and non-volatile in the absorbent before irreversibly reacting with compound A to form a stable non-volatile product.
authors.affiliation: Abbott Laboratories, Hospital Product Division Research and Development, Abbott Park, IL 60064-3500, USA.
authors.forename: D D
authors.initials: DD
authors.lastname: Cunningham
authors.forename: S
authors.initials: S
authors.lastname: Huang
authors.forename: J
authors.initials: J
authors.lastname: Webster
authors.forename: J
authors.initials: J
authors.lastname: Mayoral
authors.forename: R W
authors.initials: RW
authors.lastname: Grabenkort
mesh_terms: D000042:Absorption; D000769:Anesthesia, Inhalation; D018685:Anesthetics, Inhalation / Q000737:chemistry*; D004987:Ethers / Q000138:chemical synthesis* / Q000737:chemistry*; D006801:Humans; D006845:Hydrocarbons, Fluorinated / Q000138:chemical synthesis* / Q000737:chemistry; D008738:Methyl Ethers; D008956:Models, Chemical; D000077149:Sevoflurane; D013696:Temperature
chemical_list: D018685:Anesthetics, Inhalation; D004987:Ethers; D006845:Hydrocarbons, Fluorinated; D008738:Methyl Ethers; D000077149:Sevoflurane; C078742:fluoromethyl 2,2-difluoro-1-(trifluoromethyl)vinyl ether