Age-dependency of sevoflurane-induced electroencephalogram dynamics in children

Abstract

Background: General anaesthesia induces highly structured oscillations in the electroencephalogram (EEG) in adults, but the anaesthesia-induced EEG in paediatric patients is less understood. Neural circuits undergo structural and functional transformations during development that might be reflected in anaesthesia-induced EEG oscillations. We therefore investigated age-related changes in the EEG during sevoflurane general anaesthesia in paediatric patients. Methods: We analysed the EEGrecordedduringroutinecare ofpatients between0 and 28 yr of age (n=54), using power spectraland coherencemethods. The power spectrumquantifies the energy in the EEG at each frequency,while the coherencemeasures the frequency-dependent correlationorsynchronizationbetweenEEGsignalsat different scalp locations.WecharacterizedtheEEGasa functionof age andwithin5 age groups: gt;1 yr old(n=4), 1-6yrold(n=12), <6-14 yr old(n=14), <14-21 yr old(n=11), <21-28 yr old(n=13). Results: EEG power significantly increased from infancy through 6 yr, subsequently declining to a plateau at approximately 21 yr. Alpha (8-13 Hz) coherence, a prominent EEG feature associated with sevoflurane-induced unconsciousness in adults, is absent in patients gt;1 yr. Conclusions: Sevoflurane-induced EEG dynamics in children vary significantly as a function of age. These age-related dynamics likely reflect ongoing development within brain circuits that are modulated by sevoflurane. These readily observed paediatric-specific EEG signatures could be used to improve brain state monitoring in children receiving general anaesthesia.