Influence of the sevoflurane concentration on the occurrence of epileptiform EEG patterns

Abstract

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: 4.6±3.0 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 (42.2±17.5 s vs. 44.9 s ±14.0 s; p = 0.4073). An EEG stage of deep anaesthesia with continuous delta waves <2.0 Hz appeared significantly earlier in the 8% than in the 6% group (64.0±22.2 s vs. 77.9±20.0 s, p = 0.0022).

Conclusion: The own analysis and data from the literature show that lower endtidal concentrations of sevoflurane and shorter administration times can be used to reduce epileptiform activity during induction of sevoflurane anaesthesia in children.

Conflict of interest statement

Competing Interests: Ines Kreuzer and W. Alexander Osthaus have declared that no competing interests exist. Barbara Schultz and Arthur Schultz are members of the research group which developed the classification algorithms for depth of anaesthesia that are implemented in the EEG monitor Narcotrend. In the study presented in this article, the device was used as a means for EEG data collection. This does not alter the authors’ adherence to all the PloS One policies on sharing data and materials.

Figures

Figure 1. Typical examples for the EEG patterns delta

Figure 2. Time from start of sevoflurane administration to the first second with the patterns delta with spikes (DSP), rhythmic polyspikes (PSR), and periodic epileptiform discharges (PED) in the first 10 minutes of anaesthesia induction.

Figure 3. Endtidal sevoflurane concentrations before the first second with epileptiform activity and cumulative number of patients (%) with epileptiform potentials in section A (start of sevoflurane until start of propofol bolus).