Impact of the Narcotrend Index on propofol consumption and emergence times during total intravenous anaesthesia with propofol and remifentanil in children: a clinical utility study

Background and objective. The electroencephalographic Narcotrend Index (NI) is a measure of the hypnotic component of general anaesthesia. The purpose of this study was to evaluate the impact of Narcotrend guidance on propofol consumption and emergence times in children receiving total intravenous anaesthesia with propofol and remifentanil. Methods: Thirty children, aged 1-11 yr, scheduled for paediatric urological surgery were enrolled. Remifentanil was given to all patients at a constant infusion rate of 0.3 jig kg- I min- I throughout anaesthesia. Patients were randomly allocated to receive a continuous propofol infusion adjusted either according to a conventional clinical practice (Group C: n = 15) or guided by Narcotrend monitoring (Group NI: n = 15; target NI 60 +/- 5). All patients were connected to the Narcotrend Monitor, but in Group C the anaesthetist was blinded to the screen of the monitor. Propofol consumption (mg kg(-1)h(-1)) and emergence times (min) were the primary and secondary outcome measures. Results: Propofol consumption (median [inter-quartile range]) was significantly lower in Group NI compared to Group C (NI: 7.0[6.4-8.2] vs. G 9.3 [8.3-11.0] mg kg(-1)h(-1); P < 0.001), whereas Log-Rank-analysis revealed no intergroup difference in emergence times (Group NI: mean [95% confidence interval (CI)] 12.8 [11.2-14.4] min; Group C: 16.4 [12.6-20.2] min; P = 0.10). Haemodynamic variables remained stable within age-related limits, and there were no observations of adverse events, especially no clinical signs of intraoperative awareness in any patient. Conclusion: Narcotrend monitoring for guidance of propofol/remifentanil anaesthesia in children results in reduced propofol consumption compared to a conventional clinical practice.