[Fentanyl administration during sevoflurane anesthesia suppresses spike waves from epileptic focus on...

A 36-year-old man with intractable epileptic seizures underwent insertion of subdural electrodes on bilateral temporal lobes under air-oxygen-sevoflurane anesthesia. After the completion of the operation, we measured electrocorticogram at end-tidal sevoflurane concentration of 2.5%, 1.5%, and 1.5% with 0.1 mg intravenous fentanyl. When sevoflurane concentration was reduced to 1.5%, the incidence and voltage of the spike waves on electrocorticogram were reduced. When 0.1 mg fentanyl was intravenously administrated during 1.5% sevoflurane anesthesia, the frequency of the spike waves was further reduced. Caution should be taken when using sevoflurane-fentanyl anesthesia because this combination may interrupt identification of epileptic focus on intraoperative electrocorticogram.