[Differential reactivities of three kinds of carbon dioxide absorbents with sevoflurane]

The differential reactivities of three kinds of carbon dioxide absorbents, Soda lime, Soda lime A, and Baralyme with sevoflurane were investigated. Sevoflurane was made to react with each carbon dioxide absorbents in a glass vial or in a closed system under administration of carbon dioxide. Glass vials were kept at 55 degrees C and 70 degrees C, and three kinds of carbon dioxide absorbents were compared regarding their reactivity under each temperature. In a closed system, we also monitored the temperature of glass container which was filled with each carbon dioxide absorbent. In a glass vial, the highest reactivity of sevoflurane was found with Baralyme. Although Soda lime A decomposed sevoflurane less than Baralyme or Soda lime in glass vial, the highest reactivity of sevoflurane in a closed system was found with Soda lime A. On the other hand, Soda lime A increased the temperature of glass container most. As increasing temperature tends to promote reaction, the possibility that the high temperature of the glass container contributes to the reactivity of sevoflurane with carbon dioxide absorbents exists. These results suggest that the highest reactivity of Soda lime A with sevoflurane was caused by the highest temperature of glass container although its chemical composition makes it most reactive with sevoflurane than the others.