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Comparing Bispectral Index and Narcotrend monitors in patients undergoing major hepatobiliary surgery: a case series

Authors Davies C, Katyayani K, Kunst G, Taylor CC, Wang Y, Barber S, Milan Z

Received 10 August 2018

Accepted for publication 30 April 2019

Published 5 July 2019 Volume 2019:11 Pages 17—25


Checked for plagiarism Yes

Review by Single-blind

Peer reviewer comments 2

Editor who approved publication: Dr Stefan Wirz

Charlotte Davies,1 Katyayani Katyayani,2 Gudrun Kunst,2 Charles C Taylor,3 Yiyan Wang,3 Stuart Barber,3 Zoka Milan2

1Brighton and Sussex Medical School, Brighton, UK; 2Anaesthetic Department, King’s College Hospital, London, UK; 3Leeds School of Mathematics, Leeds, UK

Abstract: Intraoperative monitoring of brain electrical activity is the standard of care for major surgical procedures. Although UK national suggested that the Bispectral Index (BIS) and Narcotrend (NCT) depth-of-anesthesia monitors are broadly equivalent, there is contradictory evidence in the literature comparing the two monitors. In this case series, we present a comparison between BIS and NCT indices recorded in 20 patients undergoing major hepatobiliary surgery. A total of 52,562 data pairs were obtained from 20 patients. Each index was then categorized according to whether the value was below, within, or above the target range (40–60 for BIS and 27–64 for NCT). Our results indicated discordance in the clinical guidance provided by these monitors in 29.3% of cases. Different timing of data collection between the two monitors and electrode position may have contributed to these findings. These observations mean that we cannot fully rely on electroencephalography monitoring to determine the depth of anesthesia. Therefore, it is important for the anesthetist continually to perform comprehensive assessment of the depth of anesthesia, including use of depth-of-anesthesia monitors, review of clinical signs, and use of monitored anesthesia care–based techniques where appropriate. In addition, monitoring of relative changes in the BIS:NCT index ratio over time would be more clinically useful than recording absolute values.

Keywords: monitoring, cerebral, hepatobiliary, awareness, depth of anesthesia, adult

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