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A54 Comparison of Effects of different Anaesthetic Techniques on Electrocorticography in Patients undergoing Epilepsy Surgery

Background and goal of study: An estimated 5 – 10% of patients with medically intractable epilepsy need surgical therapy. Potential effect of anaesthetic on the degree and pattern of interictal epileptiform activity is an unresolved issue. The aim of our study is to compare the effects of different anaesthetic techniques on electrocorticography (ECoG) in patients undergoing epilepsy surgery, in terms of satisfactory recognition of epileptiform foci. We also compared the recovery characteristics and postoperative complications. Materials and Methods: For this prospective, randomised, double blind cross-over study, we enrolled 39 patients undergoing epilepsy surgery. Anaesthesia was induced with fentanyl 2 mcg/kg, propofol 2–3 mg/kg and rocuronium 1 mg/kg. Patients were randomised to receive isoflurane (Group I) or propofol (Group P) and oxygen (50%) with air or nitrous oxide was used as carrier gases. After exposure of brain grid electrode ECoG was recorded with both carrier gases. ECoG was analysed by a blinded neurologist. Results: Demographics, duration of surgery and anaesthesia, Intensive care unit and hospital stay were comparable in two groups. Use of nitrous oxide decreased ECoG scores in both groups but significantly in Isoflurane group [Table 1]. In Isoflurane group 89% patients were seizure free as compared to 85% in propofol group. Table 1: Intra-group comparison of the mean ECoG scores Conclusion and Discussion: Both Isoflurane and propofol are safe during epilepsy surgery. Nitrous oxide may be avoided during ECoG recording as it reduces the scores. References:Schneider F, Herzer W, Schroeder WS, et al. Effect of propofol on electrocorticography in patients with intractable epilepsy. J Neurosurg 2010; 23: 150 – 155Tripathi M, Garg A, Gaikwad S, et al. Intraoperative electrocorticography in lesional epilepsy. Epilepsy Research 2010; 89: 133 – 141