Peri- and intraoperative EEG signatures in newborns and infants.

ABSTRACT

OBJECTIVE: The electroencephalographic derived indices have been developed for adult patients, however these monitors have not been validated for infants. METHODS: Frontal EEGs were recorded in 115 infants aged <1 year [0-3-months (N = 27), 4-6-months (N = 30), 7-9-months (N = 29) and 10-12-months (N = 29)] who received general anaesthesia with sevoflurane. Total power (µV2) and relative ß-, α-, θ-, δ-power (%) were analyzed. Additionally, in 20 EEGs event marker were added (baseline, loss of consciousness, intraoperative situation, extubation) to assess perioperative EEG dynamics. RESULTS: Newborns show a mean relative δ-power at 80% in intraoperative EEG compared to infants (10-12 months) showing 47.5%. Relative ß-power and α-power are low in newborns (mean 3.2% and 4.6%; respectively), with a marked increase in the older infants (4-6 months) (mean 10.9% and 14.4%; respectively). EEG dynamic in newborns from baseline (relative δ-power of 88%) to the intraoperative situation (80.5%) are discrete. In contrast infants >6-months have a strong reduction of relative δ-power from baseline to the intraoperative situation, which corresponds to an increase of faster frequencies. CONCLUSIONS: Age dependent perioperative EEG signatures can be demonstrated in infants younger than one year. SIGNIFICANCE: We demonstrate significant differences in EEG readouts between newborns and infants which questions our monitoring systems in paediatric anaesthesia.