Sevoflurane low-flow anaesthesia: best strategy to reduce Compound A concentration.
BACKGROUND
To define the best strategy to reduce Compound A production in Sevoflurane low-flow anaesthesia by experiments in vitro and in vivo of different absorbers and different anaesthesia machines.


METHODS
In vitro Compound A has been measured at 45 degrees C in vitro following Sevoflurane interactions with potassium hydroxide, sodium hydroxide, soda lime, Dragersorb 800 Plus and Amsorb, a new absorber that does not contain sodium or potassium hydroxide. In vivo Compound A concentration in the anaesthesia circuit (inspiratory branch) has been measured using an indirect sampling method through absorber vials (SKC) with active coal granules, during low flows (500 ml/min) general anaesthesia using soda lime, Dragersorb 800 Plus or Amsorb as absorber. Compound A was also measured during low flows (500 ml/min) general anaesthesia using as carbon dioxide absorber soda lime with different anaesthesia machines.


RESULTS
In vitro at 45 degrees C Compound A concentration with soda lime and Dragersorb 800 Plus was about 10 times higher than with Amsorb. In vivo the Compound A concentrations in the inspiratory branch of the circuit were lower in the group with Amsorb.


CONCLUSIONS
The Compound A production is minimal with Amsorb as carbon dioxide absorber.
Department of Medical and Surgical Critical Care, University of Florence, Italy. aledanibatibeba@hotmail.com
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Di Filippo
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Marini
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Pacenti
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Dugheri
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Focardi
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Novelli
D000042:Absorption; D000764:Anesthesia, Closed-Circuit / Q000379:methods; D018685:Anesthetics, Inhalation / Q000008:administration & dosage*; D002245:Carbon Dioxide; D004987:Ethers / Q000032:analysis*; D006801:Humans; D006845:Hydrocarbons, Fluorinated / Q000032:analysis*; D066298:In Vitro Techniques; D008738:Methyl Ethers / Q000008:administration & dosage*; D000077149:Sevoflurane
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