Electroencephalographic Narcotrend Index monitoring during procedural sedation and analgesia in children

The impact of Narcotrend™ EEG-guided propofol administration on the speed of recovery from pediatric procedural sedation-A randomized controlled trial

BACKGROUND

Propofol is often used for procedural sedation in children undergoing gastrointestinal endoscopy. Reliable assessment of the depth of hypnosis during the endoscopic procedure is challenging. Processed electroencephalography using the Narcotrend Index can help titrating propofol to a predefined sedation level.

AIMS

The aim of this trial was to investigate the impact of Narcotrend Index-guided titration of propofol delivery on the speed of recovery.

METHODS

Children, aged 12-17 years, undergoing gastrointestinal endoscopy under procedural sedation, had propofol delivered via target controlled infusion either based on Narcotrend Index guidance (group NI) or standard clinical parameters (group C). Sedation was augmented with remifentanil in both study groups. The primary endpoint of this study was to compare the speed of fulfilling discharge criteria from the operating room between study groups. Major secondary endpoints were propofol consumption, discharge readiness from the recovery room, hypnotic depth as measured by the Narcotrend Index, and adverse events.

RESULTS

Of the 40 children included, data were obtainable from 37. The time until discharge readiness from the operating room was shorter in group NI than in group C, with a difference between medians of 4.76 minutes [95%CI 2.6 to 7.4 minutes]. The same accounts for recovery room discharge times; difference between medians 4.03 minutes [95%CI 0.81 to 7.61 minutes]. Propofol consumption and the percentage of EEG traces indicating oversedation were higher in group C than in group NI. There were no significant adverse events in either study group.

CONCLUSION

Narcotrend Index guidance of propofol delivery for deep sedation in children aged 12-17 years, underdoing gastrointestinal endoscopy results in faster recovery, less drug consumption, and fewer episodes of oversedation than dosing propofol according to clinical surrogate parameters of depth of hypnosis. The results of this study provide additional evidence in favor of the safety profile of propofol/remifentanil for procedural sedation in adequately selected pediatric patients.

A new real-time method for detecting the effect of fentanyl using the preoperative pressure pain threshold and Narcotrend index: a randomized study in female surgery patients

Individual variability in the effects of opioid analgesics such as fentanyl remains a major challenge for tailored pharmacological treatment including postoperative analgesia. This study aimed to establish a new real-time method for detecting the effects of fentanyl and their individual differences in the preoperative period, using the pressure pain threshold (PPT) and Narcotrend index (NTI) test.Eighty women undergoing elective surgery under general anesthesia were enrolled in this randomized, double-blinded, placebo-controlled study to receive either intravenous fentanyl (Group F) or saline (Group S). Before (T1) and 5 (T2) and 10 min (T3) after intravenous injection, the PPT, NTI, respiratory rate, heart rate, blood pressure, and pulse oxygen saturation were measured. The initial time at which the Narcotrend index showed a decline was also recorded.In total, 40 patients in Group S and 38 patients in Group F were included in the final analysis. At 5 min and 10 min after intravenous fentanyl administration, the analgesic effect was determined by measuring the PPT, which was significantly increased (P < 0.001), and the sedative effect was detected using the NTI, which was significantly decreased (P < 0.001). The distribution of percentage changes of the PPT and NTI showed individual differences. At T2 and T3, the absolute changes in NTI and PPT were positively correlated (r = 0.444 at T2, P = 0.005; r = 0.332 at T3, P = 0.042).Through the PPT and NTI, it was feasible to easily detect the effects of fentanyl and their individual differences in real time before induction of anesthesia in the operation room. This method could potentially be applied to preoperatively determine patients' sensitivity to fentanyl.

Improving successful rate of transcranial electrical motor-evoked potentials monitoring during spinal surgery in young children

INTRODUCTION

This prospective study was to investigate the successful rate of intraoperative motor evoked potentials (MEP) monitoring for children (<12 years old) with congenital scoliosis.

MATERIALS AND METHODS

A consecutive series of 27 young children (7 girls and 20 boys; from 1 to 11 years old) between September 2007 and November 2009, were enrolled to this study. 12 patients received general anesthesia based on TIVA, induced with propofol 2-4 mg/kg and fentanyl 3-5 µg/kg followed by a continuous infusion of propofol (20-150 µg/kg/min, at mean of 71.7 µg/kg/min). The other 15 patients received combined inhalation and intravenous anesthesia, induced with sevoflurane and fentanyl 3-5 µg/kg and maintained by sevoflurane (0.5-1%). The maintenance of anaesthesia management was performed with stable physiological parameters during surgery.

RESULTS

Intraoperative MEP monitoring was successfully performed in all patients, while SEP was successfully performed in 26 of 27 patients. There was no significant difference of successful rates between SEP and MEP monitoring (P > 0.05). As well, no difference in MEP successful rates was observed in two groups with different anesthetic techniques. No wake-up test and no post-operative neurological deficits occurred in this series of patients.

CONCLUSION

Low dose anesthesia by either TIVA with propofol or sevoflurane-based mixture anesthesia protocol can help the intraoperative spinal cord monitoring to successfully elicit MEP and perform reliable monitoring for patients below 12 years of age.

EEG under anesthesia--feature extraction with TESPAR

We investigated the problem of automatic depth of anesthesia (DOA) estimation from electroencephalogram (EEG) recordings. We employed Time Encoded Signal Processing And Recognition (TESPAR), a time-domain signal processing technique, in combination with multi-layer perceptrons to identify DOA levels. The presented system learns to discriminate between five DOA classes assessed by human experts whose judgements were based on EEG mid-latency auditory evoked potentials (MLAEPs) and clinical observations. We found that our system closely mimicked the behavior of the human expert, thus proving the utility of the method. Further analyses on the features extracted by our technique indicated that information related to DOA is mostly distributed across frequency bands and that the presence of high frequencies (> 80 Hz), which reflect mostly muscle activity, is beneficial for DOA detection.