Comparison of Bispectral Index and Composite Auditory Evoked Potential Index for Monitoring Depth of Hypnosis in Children

Abstract

Background:In pediatric patients, the Bispectral Index (BIS), derived from the electroencephalogram, and the composite ALine autoregressive index (cAAI), derived from auditory evoked potentials and the electroencephalogram, have been used as measurements of depth of hypnosis during anesthesia. The performance and reliability of BIS and cAAI in distinguishing different hypnotic states in children, as evaluated with the University of Michigan Sedation Scale, were compared.Methods: Thirty-nine children (aged 2-16 yr) scheduled to undergo elective inguinal hernia surgery were studied. For all patients, standardized anesthesia was used. Prediction probabilities of BIS and cAAI versus the University of Michigan Sedation Scale and sensitivity/specificity were calculated.Results: Prediction probabilities for BIS and cAAI during induction were 0.84 for both and during emergence were 0.75 and 0.74, respectively. At loss of consciousness, the median BIS remained unaltered (94 to 90; not significant), whereas cAAI values decreased (60 to 43; P < 0.001). During emergence, median BIS and cAAI increased from 51 to 74 (P < 0.003) and from 46 to 58 (P < 0.001), respectively. With respect to indicate consciousness or unconsciousness, 100% sensitivity was reached at cutoff values of 17 for BIS and 12 for cAAI. One hundred percent specificity was associated with a BIS of 71 and a cAAI of 60. To ascertain consciousness, BIS values greater than 78 and cAAI values above 52 were required.Conclusions: BIS and cAAI were comparable indicators of depth of hypnosis in children. Both indices, however, showed considerable overlap for different clinical conditions.

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

“…At a sensitivity of approximately 85%, they reported a higher specificity compared with our findings for the aepEX (53% vs 85%) and BIS (45% vs 80%). In a previous study by our own group, the BIS had a sensitivity of 12%, 85%, and 100%, respectively, at 100%, 61%, and 9% specificity . The discrepancy found between our study and Gajraj et al ., could be explained by the large difference in age of the study populations.…”

“…Our own research group revealed a Pk BIS of 0.74 and 0.75 in previous studies , which is close to our currently observed Pk BIS value of 0.79.…”

“…Although P k values of only 26 patients could be calculated in this study, the Pk BIS of 0.79 seems to be in accordance with those in previously published pediatric studies; Pk BIS of 0.74 and 0.75 .…”

“…This same response pattern of the aepEX was also reported in other studies, which were performed in adult patients . Interestingly, the AEP monitor/2, which also processes MLAEP, has been reported to produce a comparable increase in index values at awakening .…”

“…To our best knowledge, there are currently no published studies dealing with Pk aepEX values in pediatric patients. Two recently published studies from our own research group reported a P k value of 0.74 for the AEP monitor/2 calculated for 45 and 20 pediatric patients .…”