Document Detail


Explaining Entropy responses after a noxious stimulus, with or without neuromuscular blocking agents, by means of the raw electroencephalographic and electromyographic characteristics.
MedLine Citation:
PMID:  21051491     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Entropy™, an anaesthetic EEG monitoring method, yields two parameters: State Entropy (SE) and Response Entropy (RE). SE reflects the hypnotic level of the patient. RE covers also the EMG-dominant part of the frequency spectrum, reflecting the upper facial EMG response to noxious stimulation. We studied the EEG, EMG, and Entropy values before and after skin incision, and the effect of rocuronium on Entropy and EMG at skin incision during sevoflurane-nitrous oxide (N₂O) anaesthesia.
METHODS: Thirty-eight patients were anaesthetized with sevoflurane-N₂O or sevoflurane-N₂O-rocuronium. The biosignal was stored and analysed off-line to detect EEG patterns, EMG, and artifacts. The signal, its power spectrum, SE, RE, and RE-SE values were analysed before and after skin incision. The EEG arousal was classified as β (increase in over 8 Hz activity and decrease in under 4 Hz activity with a typical β pattern) or δ (increase in under 4 Hz activity with the characteristic rhythmic δ pattern and a decrease in over 8 Hz activity).
RESULTS: The EEG arousal appeared in 17 of 19 and 15 of 19 patients (NS), and the EMG arousal in 0 of 19 and 13 of 19 patients (P<0.01) with and without rocuronium, respectively. Both β (n=30) and EMG arousals increased SE and RE. The δ arousal (n=2) decreased both SE and RE. A significant increase in RE-SE values was only seen in patients without rocuronium.
CONCLUSIONS: During sevoflurane-N₂O anaesthesia, both EEG and EMG arousals were seen. β and δ arousals had opposite effects on the Entropy values. The EMG arousal was abolished by rocuronium at the train of four level 0/4.
Authors:
A J Aho; L-P Lyytikäinen; A Yli-Hankala; K Kamata; V Jäntti
Publication Detail:
Type:  Journal Article     Date:  2010-11-04
Journal Detail:
Title:  British journal of anaesthesia     Volume:  106     ISSN:  1471-6771     ISO Abbreviation:  Br J Anaesth     Publication Date:  2011 Jan 
Date Detail:
Created Date:  2010-12-14     Completed Date:  2011-01-18     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0372541     Medline TA:  Br J Anaesth     Country:  England    
Other Details:
Languages:  eng     Pagination:  69-76     Citation Subset:  IM    
Affiliation:
Department of Anaesthesia, Tampere University Hospital, Tampere, Finland. antti.j.aho@uta.fi
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MeSH Terms
Descriptor/Qualifier:
Adolescent
Adult
Androstanols / pharmacology
Anesthesia, Inhalation
Electroencephalography / drug effects,  methods
Electromyography / drug effects,  methods
Entropy
Humans
Middle Aged
Monitoring, Intraoperative / methods*
Neuromuscular Nondepolarizing Agents / pharmacology*
Signal Processing, Computer-Assisted
Skin / surgery
Young Adult
Chemical
Reg. No./Substance:
0/Androstanols; 0/Neuromuscular Nondepolarizing Agents; 143558-00-3/rocuronium

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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