Entropy indices vs the bispectral index™ for estimating nociception during sevoflurane anaesthesia

Takamatsu, Isao; Ozaki, Makoto; Kazama, Tomiei

doi:10.1093/bja/ael050

Cited by 78 publications

(63 citation statements)

References 19 publications

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“…In some studies, no premedication was allowed, 7,11,24 while in others, intravenous induction agents were avoided and anaesthesia was induced using a volatile anaesthetic and/or N 2 O. 2,5,10 Although GABA A agonists, such as midazolam, may decrease the analgesic effect of N 2 O, a small dose (7.5 mg) was administered two hours preoperatively in our study. It is therefore unlikely that it exerted a signi cant in uence at the time of induction of anaesthesia.…”

Section: Resultsmentioning

confidence: 93%

“…1,2 Anaesthetic drugs exert certain group-speci c effects on the EEG, the diversity of which may in uence the ability of various EEG-based monitors to evaluate consciousness, particularly when drugs with differing EEG effects are administered concurrently.…”

Section: Introductionmentioning

confidence: 99%

“…This may be due to the absence of surgical stimulation in the presence of sevo urane and at an EMAC value greater than unity. It therefore appears that entropy decreases with the addition of > 60% N 2 O to approximately 1 MAC sevo urane and that this occurs in the presence of as well as in the absence of noxious stimuli.…”

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confidence: 99%

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Entropy of the electroencephalogram as applied in the M-Entropy S/5™ Module (GE Healthcare) during increases in nitrous oxide and constant sevoflurane concentrations

Smith

Spijkerman

Becker

et al. 2010

Southern African Journal of Anaesthesia and Analgesia

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Background: It has been suggested that spectral entropy of the electroencephalogram as applied in the M-Entropy S/5 TM Module (GE Healthcare) does not detect the effects of nitrous oxide (N 2 O). The aim of this study was to investigate the effect on entropy by graded increases in N 2 O concentrations in the presence of a constant concentration of sevo urane, in the absence of surgical stimulation. Method: This single-blind, randomised study was conducted at an altitude of approximately 1 400 m. Patients received sevo urane 2% (1.7% at sea level) and N 2 O, at end-tidal concentrations of 0%, 10%, 20%, 30%, 40%, 50%, 60% or 70% (equivalent to 8.5%, 17%, 25.5%, 34%, 42.6%, 51.1% and 59.6% at sea level). Entropy was measured before, during and after N 2 O administration. The absolute changes and ratios o f entropy relative to the baseline were calculated. Between-and within-group comparisons were made using analysis of variance and covariance. Results: None of the entropy variables differed signi cantly within and between groups before and after N 2 O administration. Within-group analysis revealed that entropy during N 2 O administration was signi cantly lower than before or after N 2 O administration (P < 0.007). While a minor clinical but statistically signi cant linear relationship was observed between increasing N 2 O concentration and decreasing entropy from N 2 O 0% to 60%, a steeper and clinically important decrease (relative change > 20%) was noted at N 2 O > 60% (> 51% at sea level). Conclusions: The M-Entropy Module S/5TM responds to increasing concentrations of N 2 O in the presence of 2% (1.7% at sea level) sevo urane, in the absence of surgical stimulation. There is a linear relationship between increasing N 2 O concentrations and decreasing entropy with a steep and clinically important decrease at N 2 O > 60% (> 51% at sea level). The in uence of ambient pressure on the partial pressures, which determine the effects of anaesthetic agents, must be taken into account.

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Section: Resultsmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

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Entropy of the electroencephalogram as applied in the M-Entropy S/5™ Module (GE Healthcare) during increases in nitrous oxide and constant sevoflurane concentrations

Smith

Spijkerman

Becker

et al. 2010

Southern African Journal of Anaesthesia and Analgesia

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“…(17) It has been reported that excitability of subcortical structures evoked by noxious stimuli will increase the difference between RE and SE. Takamastu and colleagues also reported that frontal Electromyogram may be of value in assessing adequacy of anaesthesia and also reflects nociception, but it did not correlate with the intensity of the stimulation (18) .…”

Section: Discussionmentioning

confidence: 99%

To Compare the Dose of Propofol for Induction of Anaesthesia by Entropy Monitoring against Standard Induction dose in Elderly Patients

Zohail¹

2017

jmscr

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“…Its gradient with SE has been proposed to reflect the balance between nociception and anti-nociception during anesthesia. 30 The PSI is derived from 4 EEG channels, and has been designed to be less dependent on anesthetic drug combination. 31 The PSI algorithm incorporates relative activity in specific frequency bands, interhemispheric coherence information, as well as anteroposterior frequency and phase relationships.…”

Section: The Hypnotic Component: Prevention Of Intraoperative Awarenessmentioning

confidence: 99%

How Electroencephalography Serves the Anesthesiologist

et al. 2014

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Major clinical endpoints of general anesthesia, such as the alteration of consciousness, are achieved through effects of anesthetic agents on the central nervous system, and, more precisely, on the brain. Historically, clinicians and researchers have always been interested in quantifying and characterizing those effects through recordings of surface brain electrical activity, namely electroencephalography (EEG). Over decades of research, the complex signal has been dissected to extract its core substance, with significant advances in the interpretation of the information it may contain. Methodological, engineering, statistical, mathematical, and computer progress now furnishes advanced tools that not only allow quantification of the effects of anesthesia, but also shed light on some aspects of anesthetic mechanisms. In this article, we will review how advanced EEG serves the anesthesiologist in that respect, but will not review other intraoperative utilities that have no direct relationship with consciousness, such as monitoring of brain and spinal cord integrity. We will start with a reminder of anesthestic effects on raw EEG and its time and frequency domain components, as well as a summary of the EEG analysis techniques of use for the anesthesiologist. This will introduce the description of the use of EEG to assess the depth of the hypnotic and anti-nociceptive components of anesthesia, and its clinical utility. The last part will describe the use of EEG for the understanding of mechanisms of anesthesia-induced alteration of consciousness. We will see how, eventually in association with transcranial magnetic stimulation, it allows exploring functional cerebral networks during anesthesia. We will also see how EEG recordings during anesthesia, and their sophisticated analysis, may help corroborate current theories of mental content generation.

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Entropy indices vs the bispectral index™ for estimating nociception during sevoflurane anaesthesia

Abstract: Noxious stimulation increased the difference between response entropy and state entropy. However, an increase in the difference does not always indicate inadequate analgesia and should be interpreted carefully during anaesthesia.

Cited by 78 publications

References 19 publications

Entropy of the electroencephalogram as applied in the M-Entropy S/5™ Module (GE Healthcare) during increases in nitrous oxide and constant sevoflurane concentrations

Entropy of the electroencephalogram as applied in the M-Entropy S/5™ Module (GE Healthcare) during increases in nitrous oxide and constant sevoflurane concentrations

To Compare the Dose of Propofol for Induction of Anaesthesia by Entropy Monitoring against Standard Induction dose in Elderly Patients

How Electroencephalography Serves the Anesthesiologist

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