Background and Goal of Study: Emergence delirium (ED) is the most frequent brain dysfunction in children recovering from general anaesthesia. Postoperative delirium is related to prolonged duration of deep anaesthesia including burst suppression periods in elderly1,2. In children depth of anaesthesia as measured by Bispectral Index shows no correlation with ED3,4. The aim of this prospective, observational study (NCT02481999) was to determine whether the occurrence and duration of burst suppression (BS) periods influences the incidence of ED.
Materials and Methods: 100 children, aged 0.5 – 8 years, with planned surgery were included. Bodyweight adapted oral premedication with midazolam was administered in all children. Patients received i.v. induction with propofol (mg/kg) and/or mask induction with sevoflurane (etVol%) according to clinical needs. Bi-frontal EEG was recorded from start of anaesthesia until extubation, throughout this time period duration of burst suppression was visually analyzed (EEG viewer software / 50µV / 1s/div). Depth of anaesthesia as measured by Narcotrend Index (NI) was determined. ED was assessed during stay in the recovery room using the Pediatric Assessment of Emergence Delirium (PAED) Score. 
Results and Discussion: 40 children developed ED (ED-group), whereas 60 children did not (Non-ED group). No significant differences in the occurrence (ED 47% vs. Non-ED 55%, OR 1.4 (0.6 / 3.1); p=0.541) and duration of BS (ED 475 + 538sec vs. Non-ED 645 + 604sec; p=0.174; Mann-Whitney-U Test) were seen with respect to ED (Fig 1). Depth of anaesthesia did not differ between the groups (mean NI: Non-ED 46 + 13 vs. ED 49 + 12 mean NI; p=0.597; Mann-Whitney-U Test).  
Overall, 50% of the children displayed BS, occurring mainly within 5min after start of anaesthesia (onset BS: 223sec (123/412)). Mixed anaesthesia induction - Sevoflurane and Propofol – led to an increased incidence of BS (mixed induction 68%; vs. Sevoflurane 24% and Propofol 46%; OR 3.3; 95% CI 1.4/7.8), p=0.008). A higher concentration of oral midazolam premedication was positively correlated with prolonged BS duration (R2 cubic = 0.133, p=0.021). 
Conclusion: Our data revealed no significant correlation between the occurrence and duration of BS and the incidence of ED. BS, facilitated by a mixed induction and higher concentrations of midazolam, does not seem to have an unfavourable impact on cerebral function in children. 


06 / Emergence Delirium in children is not related to intraoperative Electroencephalogram suppression – findings from a prospective, observational study