Influence of the Sevoflurane Concentration on the Occurrence of Epileptiform EEG Patterns

Objectives and Aim: This study was performed to analyse the effects of different sevoflurane concentrations on the incidence of epileptiform EEG activity during induction of anaesthesia in children in the clinical routine. Background: It was suggested in the literature to use sevoflurane concentrations lower than 8 % to avoid epileptiform activity during induction of anaesthesia in children. Methods: 100 children (age: 4.663.0 years, ASA I–III, premedication with midazolam) were anaesthetized with 8% sevoflurane for 3 min or 6 % sevoflurane for 5 min in 100 % O2 via face mask followed by 4 % sevoflurane until propofol and remifentanil were given for intubation. EEGs were recorded continuously and were analysed visually with regard to epileptiform EEG patterns. Results: From start of sevoflurane until propofol/remifentanil administration, 38 patients (76%) with 8 % sevoflurane had epileptiform EEG patterns compared to 26 patients (52%) with 6 % (p = 0.0106). Epileptiform potentials tended to appear later in the course of the induction with 6 % than with 8%. Up to an endtidal concentration of 6 % sevoflurane, the number of children with epileptiform potentials was similar in both groups (p = 0.3708). The cumulative number of children with epileptiform activity increased with increasing endtidal sevoflurane concentrations. The time from start of sevoflurane until loss of consciousness was similar in patients with 8 % and 6 % sevoflurane (42.2617.5 s vs. 44.9 s 614.0 s; p = 0.4073). A