Evaluation of the aepEX™ monitor of hypnotic depth in pediatric patients receiving propofol-remifentanil anesthesia

Midlatency auditory evoked potentials during anesthesia in children: A narrative review

The brain is considered as the major target organ of anesthetic agents. Despite that, a reliable means to monitor its function during anesthesia is lacking. Mid latency auditory evoked potentials are known to be sensitive to anesthetic agents and might therefore be a measure of hypnotic state in pediatric patients. This review investigates the available literature describing various aspects of mid latency auditory evoked potential monitoring in pediatric anesthesia.

Electroencephalography: Clinical Applications During the Perioperative Period

Electroencephalography (EEG) monitoring has become technically feasible in daily clinical anesthesia practice. EEG is a sensitive method for detecting neurophysiological changes in the brain and represents an important frontier in the monitoring and treatment of patients in the perioperative period. In this review, we briefly introduce the essential principles of EEG. We review EEG application during anesthesia practice in the operating room, including the use of processed EEG in depth of anesthesia assessment, raw EEG monitoring in recognizing brain states under different anesthetic agents, the use of EEG in the prevention of perioperative neurocognitive disorders and detection of cerebral ischemia. We then discuss EEG utilization in the intensive care units, including the use of EEG in sedative level titration and prognostication of clinical outcomes. Existing literature provides insight into both the advances and challenges of the clinical applications of EEG. Future study is clearly needed to elucidate the precise EEG features that can reliably optimize perioperative care for individual patients.

Agreement of cerebral state index and glasgow coma scale in brain-injured patients

Background:

Variables derived from electroencephalogram like cerebral state index (CSI) have been used to monitor the anesthesia depth during general anesthesia. Observed evidences show such variables have also been used as a detector of brain death or outcome predictor in traumatic brain-injured (TBI) patients.

Objectives:

The current study was designed to determine the correlation between Glasgow coma score (GCS) and CSI among TBI patients.

Patients and Methods:

In 60 brain-injured patients who did not need and receive sedatives, GCS and CSI were daily measured during the first ten days of their hospital stay. Correlation between GCS and CSI was studied using the Pearson's correlation test. The Gamma agreement coefficient was also calculated between the two variables for the first day of hospitalization.

Results:

A significant correlation coefficient of 0.611-0.796 was observed between CSI and GCS in a ten-day period of the study (P < 0.001). Gamma agreement coefficient was 0.79 (P < 0.001) for CSI and GCS for the first day of hospitalization. An increased daily correlation was observed in both CSI and GCS values. However, this increase was less significant in CSI compared with the GCS.

Conclusions:

A statistically significant correlation and agreement was found between GCS and CSI in the brain-injured patients and GCS was also found to be more consistent and reliable compared with CSI.

Evaluation of the auditory evoked potentials derived aepEX(™) as a measure of hypnotic depth in pediatric patients receiving sevoflurane-remifentanil anesthesia

BACKGROUND

The aepEX is a measure of depth of hypnosis (DoH), derived from processed mid-latency auditory evoked potentials.

OBJECTIVES

To evaluate the aepEX as a measure of DoH in children receiving sevoflurane-remifentanil anesthesia.

METHODS

aepEX and bispectral index (BIS) were recorded simultaneously in 75 children, (1-3, 3-6, and 6-18 years), receiving sevoflurane at endtidal concentrations (ETsevo ) between 1.5 and 0.5 MAC. The ETsevo at which the aepEX and BIS had a value of 50 (EC50aep EX and EC50BIS ) was calculated by nonlinear regression analysis. The accuracy of aepEX and BIS to predict the DoH was assessed by prediction probability (Pk ) and receiver operating characteristics (ROC) analysis.

RESULTS

Seventy-four children were included for analysis. The EC50aep EX (2.68%) and EC50BIS (2.10%) were comparable; the same accounts for the EC50aep EX of the different age groups and the EC50aep EX and EC50BIS of corresponding age groups. The EC50BIS in children aged 1-3 years was lower than in the older age groups (P < 0.05). Pk values of the aepEX (0.32, CI 95% 0.08-0.56) and BIS (0.47, CI 95% 0.19-0.75) were comparable. The area under the ROC curve was 0.72 (CI 95%: 0.62-0.82) and 0.67 (CI95%: 0.56-0.77) for the aepEX and BIS, respectively (P = 0.54). Optimal cutoff values were >60 (aepEX) and >68 (BIS), with corresponding specificities 91%, CI 95%: 80-97% (aepEX) and 66%, CI 95%: 52-77% (BIS).

CONCLUSIONS

In this study with children receiving sevoflurane anesthesia, the aepEX outperformed the BIS in distinguishing unconsciousness from consciousness. Both indices performed equally bad in differentiating different levels of DoH.