The EEG During Anaesthesia In Infants And Children

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Andrew Davidson^1,3, Steven Sale², Connie Wong³, Zeke Cahn⁴, Stephen McKeever³ Chris Williams⁵

1. Department of Anaesthesia & Pain Management, Royal Children’s Hospital, Melbourne
2. Department of Anaesthesia, Frenchay Hospital, Bristol, UK.
3. Murdoch Childrens Research Institute
4. Brainz Instruments Pty Ltd, Auckland
5. Liggins Institute, University of Auckland, Auckland, New Zealand

Purpose of Study

EEG-derived depth of anaesthesia monitors are based upon well described and reproducible changes in the EEG during most forms of anaesthesia in adults. There is increasing evidence these monitors perform poorly in small children and the characteristics of the EEG during anaesthesia in children is poorly described. This study aimed to describe the changes in three representative parameters of the EEG during emergence in children and infants.

Method

After ethics approval and parental consent, 64 children aged 9 days to 12 years were enrolled in this observational blinded physiological study. Anaesthesia was given at the discretion of the anaesthetist who was blinded to the EEG recordings. EEG was recorded from after induction, to after awakening using a ReBRM brain monitor in left and right parietal and frontal montages. Artifact free data was analysed at a point of equilibrium during anaesthesia, when the volatile agent was discontinued and at the point of awakening. From this data spectral edge frequency (SEF), aEEGmin and intensity were calculated. For analysis children were divided into three age groups; 0-6 months, 6-24 months and 2-12 years. A Two-way ANOVA was used to compare impact of montage, age and epoch on each EEG parameter.

Result

Fifty-seven children had artifact free EEG data. At equilibrium the forehead montages had higher intensity and aEEG compared to parietal (P=0.03, P<0.001). The intensity and aEEGmin decreased during emergence in older children but not in infants (P<0.001). SEF did not change during emergence in children in the younger age groups, but increased in children aged 2-12 (P=0.01). Throughout emergence, infants demonstrated a discontinuous EEG pattern with intermittent bursts separated with low amplitude.

Conclusion

During emergence from anaesthesia the EEG in infants is fundamentally different to the EEG in older children. This study supports the need for specific infant derived algorithms if EEG-derived anaesthesia depth monitors are to be used in infants.

Time of Presentation
1030