EEG dynamics in children from preanesthetic awake state, under general anaesthesia until regain of consciousness

Objective Little is known about electroencephalographic (EEG) neuromonitoring in young children during anaesthesia and their specific EEG characteristics. Devices have been developed for adult patients, and validation in this young patient population is often lacking. However, young children are particularly vulnerable to anaesthesia, and the effects of anaesthetics on brain development are uncertain. The purpose of this study was to characterise 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 anaesthesia at Charité - Campus Virchow Klinik (CVK). For data acquisition, the Narcotrend Monitor was used, and the raw EEG files were further analysed in their frequency bands. The patient cohort was divided into four age groups (0–5 months, 6–11 months, 12–23 months, 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 anaesthesia, with a step increase at loss of consciousness, which is more pronounced in older children. Intraoperatively, alpha- and beta-activity emerges at the age of six months and is 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 characterised again by a predominant delta-activity in all age groups. Conclusion In this study, we characterised differences in the perioperative EEG signatures of children from 1 month to 8 years from the preoperative awake state during induction and general anaesthesia until they regained consciousness from general anaesthesia. 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 approval from the Charité – University Medicine Berlin's ethics committee (EA2/027/15) and was registered at clinicaltrials.gov (23rd of June 2015/NCT02481999).