Document Detail


Response entropy increases during painful stimulation.
MedLine Citation:
PMID:  15840994     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Frontal electromyography (FEMG) may increase during painful stimulation and indicate patient arousal. The Datex-Ohmeda Entropy Module calculates state entropy (SE) of the electroencephalogram (EEG; 0.8-32 Hz) and response entropy (RE) of EEG and FEMG (0.8-47 Hz). We determined whether RE increases above SE (RE--SE), an indication of FEMG, increase during painful stimuli and if this is related to paralysis or level of anesthesia. With the unanesthetized baseline measurement, SE was 89 +/- 2 and RE was 98 +/- 2. During paralysis and anesthesia with either 0.8% (n = 10) or 1.4% (n = 10) isoflurane, SE decreased to 63 +/- 7 and 34 +/- 14, respectively, and the RE--SE difference decreased 90%. Before recovery from paralysis, arterial catheter or head pin placement increased RE--SE above unanesthetized levels in eight patients (five treated with 0.8% and three with 1.4% isoflurane), consistent with an increase in FEMG. The elevated RE--SE difference was related to a significant increase in SE, blood pressure, and heart rate. After recovery from paralysis, tetanic stimulation of the ulnar nerve increased the RE--SE difference above unanesthetized levels in 8 of 20 patients (6 treated with 0.8% and 2 with 1.4% isoflurane). In these patients, SE increased significantly. The remaining 12 patients did not show an increase in RE--SE during tetanic stimulation and SE did not increase. We conclude that increased RE during painful stimulation was not dependent on recovery from paralysis but was seen more often in patients anesthetized with 0.8% compared with 1.4% isoflurane. This suggests that RE reflects FEMG and may be useful to identify inadequate anesthesia and patient arousal during painful stimuli.
Authors:
Peggy Wheeler; William E Hoffman; Verna L Baughman; Heidi Koenig
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Publication Detail:
Type:  Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of neurosurgical anesthesiology     Volume:  17     ISSN:  0898-4921     ISO Abbreviation:  J Neurosurg Anesthesiol     Publication Date:  2005 Apr 
Date Detail:
Created Date:  2005-04-20     Completed Date:  2005-06-08     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8910749     Medline TA:  J Neurosurg Anesthesiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  86-90     Citation Subset:  IM    
Affiliation:
Anesthesiology Department, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
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MeSH Terms
Descriptor/Qualifier:
Aged
Arousal / physiology
Blood Pressure / physiology
Brain / physiopathology
Electric Stimulation
Electroencephalography
Electromyography
Entropy
Female
GABA Modulators / pharmacology
Heart Rate / physiology
Humans
Male
Midazolam / pharmacology
Middle Aged
Neurosurgical Procedures
Pain / physiopathology*
Spine / surgery
Chemical
Reg. No./Substance:
0/GABA Modulators; 59467-70-8/Midazolam

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


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