1. Impact of Narcotrend EEG-guided Propofol Administration
One study conducted in 2018 measured recovery speed from sedation for pediatric patients. This prospective, randomized, controlled double blind study was designed to assess whether outcomes were affected by the use of Narcotrend Index monitoring during intravenous propofol delivery for deep sedation in children aged 12–17 years.
The sample size was relatively small—only 41 patients—but the results were clear. They provided additional evidence in favor of the safety profile of propofol/remifentanil for procedural sedation in adequately selected pediatric patients. Patients whose titration of propofol delivery was informed by the Narcotrend Index had lower drug consumption, fewer episodes of over-sedation, and faster recovery times.
Weber F, Walhout LC, Escher JC. The impact of Narcotrend EEG-guided propofol administration on the speed of recovery from pediatric procedural sedation—A randomized controlled trial. Paediatr Anaesth. 2018 May; 28(5):443-449.
2. Impact of the Narcotrend Index on Propofol Consumption and Emergence Times
One researcher in the study cited above participated in a similar evaluation in 2005. Its purpose was to evaluate the impact of Narcotrend guidance on propofol consumption and emergence times in children receiving total intravenous anaesthesia with propofol and remifentanil.
The study enrolled 30 children, aged 1–11, scheduled for pediatric urological surgery. All received remifentanil at a constant infusion rate of 0.3 microg kg [-1] min[-1] throughout anesthesia. Patients were randomly allocated to receive a continuous propofol infusion adjusted according to 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 anesthetist was blinded to the monitor screen. Primary and secondary outcome measures were propofol consumption (mg kg[-1]h[-1]) and emergence times (min).
Propofol consumption (median [inter-quartile range]) was significantly lower in Group NI compared to Group C (NI: 7.0 [6.4–8.2] vs. C: 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). Hemodynamic variables remained stable within age-related limits, and there were no observations of adverse events, especially no clinical signs of intraoperative awareness.
Weber F1, Pohl F, Hollnberger H, Taeger K. 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. Eur J Anaesthesiol. 2005 Oct;22(10):741-7.
3. Optimization of Initial Propofol Bolus Dose for EEG Narcotrend Index-guided Transition from Sevoflurane Induction to Intravenous Anesthesia in Children
This study also had a small sample size, but the findings deserve mention. This prospective clinical observational study was meant to identify the optimal initial propofol bolus dose for a smooth transition from sevoflurane induction to TIVA using the EEG Narcotrend Index (NI).
The study included 50 children aged 1–8 scheduled for elective surgery. After sevoflurane induction and establishment of intravenous access, a propofol bolus dose range 0-5 mg⋅kg-1 was administered at the anesthesia practitioner’s discretion to maintain NI between 20 and 64, and sevoflurane was stopped. Anesthesia was continued as TIVA with a propofol infusion dose of 15 mg/kg/h for the first 15 min, followed by stepwise reduction according to McFarlan’s pediatric infusion regime, and remifentanil 0.25 μg/kg/min. End-tidal concentration of sevoflurane, NI, and hemodynamic data were recorded during the entire period. Propofol plasma concentrations were calculated using the paedfusor dataset and a TIVA simulation program.
Sevoflurane induction followed by intravenous anesthesia is a widely used technique to combine the benefits of an easier and less traumatic venipuncture after sevoflurane inhalation with a recovery with less agitation, nausea, and vomiting after TIVA. Combination of two different anesthetics may lead to unwanted burst suppression in the EEG during the transition phase. Narcotrend monitoring can help anesthesia practitioners maintain desired sedation levels.
Dennhardt N, Boethig D, Beck C, Heiderich S, Boehne M, Leffler A, Schultz B, Sümpelmann R. Optimization of initial propofol bolus dose for EEG Narcotrend Index-guided transition from sevoflurane induction to intravenous anesthesia in children. Paediatr Anaesth. 2017 Apr;27(4):425-432.
4. Effect of Age on Narcotrend Index Monitoring during Sevoflurane Anesthesia in Children Below 2 Years of Age
This study included 61 children aged 0–24 months undergoing general anesthesia with sevoflurane and remifentanil for elective surgery. It investigated the percentage of differentiated electroencephalograms and the correlation between multiples of minimal alveolar sevoflurane concentration and the Narcotrend Index by age group.
The objective of this prospective clinical observational study was to assess the feasibility and performance of the Narcotrend monitor in children <2 years within a clinical setting. Prediction probability was used to evaluate the performance of the Narcotrend Index for differentiation between consciousness and unconsciousness and between different sevoflurane concentrations.
The study found that the percentage of differentiated electroencephalograms increased with increasing age (0–3 months: 23.8%, 4–5 months: 87.5%, 6–11 months: 92.3%, 12–24 months: 100%). The overall prediction probability of Narcotrend Index was 1.0 (SE 0.05) for differentiation between awake and loss of consciousness and 1.0 (SE 0.01) for differentiation between anesthetized and return of consciousness.
The Narcotrend monitor indicated a Narcotrend Index in most infants and young children starting from 4 months with significant correlation to and acceptable prediction probability for minimal alveolar sevoflurane concentration.
Dennhardt N, Arndt S, Beck C, Boethig D, Heiderich S, Schultz B, Weber F, Sümpelmann R. Effect of age on Narcotrend Index monitoring during sevoflurane anesthesia in children below 2 years of age. Paediatr Anaesth. 2018 Feb;28(2):112-119