Effect of remifentanil on intraoperative ECoG - A comparison with sevoflurane

Background : In surgeries for epilepsy, electrocorticography (ECoG) enables tailored resection of the epileptogenic brain and pharmacological stimulation should be employed in surgeries under general anesthesia. To identify the efficacy of continuous remifentanil in surgeries for epilepsy, ECoG findings with remifentanil and those with sevoflurane were compared. Methods : Sixteen patients with intractable epilepsy were included with institutional ethics committee approval and informed consent. General anesthesia was induced and maintained with sevoflurane, remifentanil and rocuronium. After dural opening, ECoG recordings were obtained before stimulation, with sevoflurane-stimulation (ET-sevoflurane 2.5%) and with remifentanil-stimulation (0.7 μg·kg^-1·min^-1 for 2 min followed by 0.35 μ g·kg^-1·min^-1). Results : In 11 of the 16 cases, activation was confirmed with remifentanil and numbers of spikes with remifentanil- and sevoflurane-stimulation were larger than those before stimulation. Conclusions : There have been some reports on bolus remifentanil on ECoG but not on its continuous infusion. This is the first report of the effect of remifentanil on ECoG as compared to sevoflurane. In this study, continuous infusion of remifentanil showed a stimulating effect on ECoG with the same potency as sevoflurane. Remifentanil may be used as an alternative to sevoflurane.