Response of the GE Entropy™ monitor to neuromuscular block in awake volunteers

Schuller, Peter J., Pretorius, Jan P.G., and Newbery, Kym B. (2023) Response of the GE Entropy™ monitor to neuromuscular block in awake volunteers. British Journal of Anaesthesia, 131 (5). pp. 882-892.

[img] PDF (Published Version) - Published Version
Restricted to Repository staff only

View at Publisher Website: https://doi.org/10.1016/j.bja.2023.08.01...
 
2


Abstract

Background: The GE Entropy™ monitor analyses the frontal electroencephalogram (EEG) and generates two indices intended to represent the degree of anaesthetic drug effect on the brain. It is frequently used in the context of neuromuscular block. We have shown that a similar device, the Bispectral Index monitor (BIS), does not generate correct values in awake volunteers when neuromuscular blocking drugs are administered.

Methods: We replayed the EEGs recorded during awake paralysis from the original study to an Entropy monitor via a calibrated electronic playback system. Each EEG was replayed 30 times to evaluate the consistency of the Entropy output.

Results: Both State Entropy and Response Entropy decreased during periods of neuromuscular block to values consistent with anaesthesia, despite there being no change in conscious state (State Entropy <60 in eight of nine rocuronium trials and nine of 10 suxamethonium trials). Entropy values did not return to pre-test levels until after the return of movement. Entropy did not generate exactly the same results when the same EEG was replayed multiple times, which is primarily because of a cyclical state within the Entropy system itself.

Conclusions: The GE Entropy™ monitor requires muscle activity to generate correct values in an awake subject. It could therefore be unreliable at detecting awareness in patients who have been given neuromuscular blocking drugs. In addition, Entropy does not generate the same result each time it is presented with the same EEG.

Item ID: 80823
Item Type: Article (Research - C1)
ISSN: 1471-6771
Keywords: bispectral index, depth of anaesthesia monitor, E-Entropy, electroencephalography, measurement techniques, spectral analysis
Copyright Information: Crown Copyright © 2023 Published by Elsevier Ltd on behalf of British Journal of Anaesthesia. All rights reserved. For Permissions, please email: permissions@elsevier.com
Date Deposited: 20 Feb 2024 02:18
FoR Codes: 32 BIOMEDICAL AND CLINICAL SCIENCES > 3202 Clinical sciences > 320201 Anaesthesiology @ 100%
SEO Codes: 20 HEALTH > 2001 Clinical health > 200103 Human pain management @ 100%
Downloads: Total: 2
More Statistics

Actions (Repository Staff Only)

Item Control Page Item Control Page