Compound A production from sevoflurane is not less when KOH-free absorbent is used in a closed-circuit lung model system.
In an in vitro study, less compound A was formed when a KOH-free carbon dioxide absorbent was used. To confirm this observation we used a lung model in which carbon dioxide was fed in at 160 ml min(-1) and sampling gas was taken out for analysis at 200 ml min(-1); ventilation aimed for a PE'CO2 of 5.4 kPa. The soda lime canister temperatures in the inflow and outflow ports (Tin and Tout) were recorded. In six runs of 240 min each, a standard soda lime, Sodasorb (Grace, Epernon, France) was used and in eight runs KOH-free Sofnolime (Molecular Products, Thaxted, UK) was used. Liquid sevoflurane was injected using a syringe pump to obtain 2.1% E'. Compound A was measured by capillary gas chromatography combined with mass spectrometry. Median (range) compound Ainsp increased to a maximum of 22.7 (7.9) ppm for Sodasorb and 33.1 (20) for Sofnolime at 60 min and decreased thereafter; the difference between groups was significant (P<0.05) at each time of analysis up to 240 min. The canister temperatures were similar in both groups and increased to approximately 40 degrees C at 240 min. Contrary to expectation, compound A concentrations were greater with the KOH-free absorbent despite similar canister temperatures with both absorbents.
Versichelen
L
L
Department of Anaesthesia, Ghent University, Gent, Belgium.
Bouche
M P
MP
Struys
M
M
Van Bocxlaer
J
J
Mortier
E
E
de Leenheer
A P
AP
Rolly
G
G
D000042:Absorption; D000764:Anesthesia, Closed-Circuit; D018685:Anesthetics, Inhalation / Q000737:chemistry*; D017610:Calcium Compounds / Q000737:chemistry*; D002245:Carbon Dioxide / Q000737:chemistry; D004987:Ethers / Q000737:chemistry*; D006801:Humans; D006845:Hydrocarbons, Fluorinated / Q000737:chemistry*; D006878:Hydroxides / Q000737:chemistry; D008168:Lung; D008738:Methyl Ethers / Q000737:chemistry*; D008954:Models, Biological; D010087:Oxides / Q000737:chemistry*; D017680:Potassium Compounds / Q000737:chemistry; D000077149:Sevoflurane; D012972:Sodium Hydroxide / Q000737:chemistry*
D018685:Anesthetics, Inhalation; D017610:Calcium Compounds; D004987:Ethers; D006845:Hydrocarbons, Fluorinated; D006878:Hydroxides; D008738:Methyl Ethers; D010087:Oxides; D017680:Potassium Compounds; D002245:Carbon Dioxide; D000077149:Sevoflurane; C004569:soda lime; D012972:Sodium Hydroxide; C078742:fluoromethyl 2,2-difluoro-1-(trifluoromethyl)vinyl ether; C029943:potassium hydroxide