EEG Dynamics in Children Before, During and After General Anesthesia

BACKGROUND: Age-specific EEG signatures during anesthesia are described in pediatrics, and perioperative monitoring is increasingly advocated; yet most indices and algorithms derive from adult data and may not generalize to early development. AIMS: The purpose of this study was to characterize perioperative frontal EEGs in young children younger than 8 years. METHODS: A total of 147 frontal EEGs from children ranging from 1 month to 8 years of age were recorded prospectively under general anesthesia at Charité-Campus Virchow Klinik (CVK). For data acquisition, the Narcotrend Monitor was used, and the raw EEG files were further analyzed in their frequency bands. The patient cohort was divided into four age groups (0-5, 6-11, 12-23, and > 24 months), and EEG signatures were compared between the age groups. RESULTS: Delta activity is the predominant frequency in all age groups already in the awake state before induction of anesthesia, with a step increase at loss of consciousness, which is more pronounced in older children. Intraoperatively, alpha- and beta-activity emerge at the age of 6 months and are greater in the older age groups. Infants (0-5 months) remain with a high amount of Delta activity intraoperatively. With the return of consciousness, the faster frequencies gradually decrease, and the EEG is characterized again by a predominant delta-activity in all age groups. CONCLUSIONS: In this study, we characterized differences in the perioperative EEG signatures of children from 1 month to 8 years from the preoperative awake state during induction and general anesthesia until they regained consciousness from general anesthesia. The EEG readouts differ across age groups, and age-adapted monitoring systems are needed to protect this vulnerable patient group from over- and undersedation. TRIAL REGISTRATION: This study was approved by the Charité-University Medicine Berlin's ethics committee (EA2/027/15) and was registered at clinicaltrials.gov (23rd of June 2015/NCT02481999).