Effects of etomidate on bispectral index scale and spectral entropy during induction of anesthesia by means of the raw electroencephalographic and electromyographic characteristics

Kim, Hyun-Mok; Shin, Sang‐Wook; Yoon, Jeong Whan; Lee, Hyeon-Jeong; Kim, Kyung-Hoon; Baik, Seong-Wan

doi:10.4097/kjae.2012.62.3.230

Cited by 12 publications

(8 citation statements)

References 17 publications

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“…Even in awake persons, neuromuscular block decreased the BIS values. 7,8 Kim et al 5 reported that BIS, RE, and SE values were all decreased and became similar after injection of the muscle relaxant in patients with myoclonus during induction of anesthesia with etomidate. Additionally, neuromuscular block reversal by pyridostigmine significantly increased RE values in a prospective study.…”

Section: Discussionmentioning

confidence: 95%

“…3,4 The Entropy TM module may be more affected by EMG more compared with BIS, which is mainly influenced by EEG. 5 The EMG activity is most likely to increase especially the level of total intravenous anesthesia using a low dose of propofol and remifentanil without a muscle relaxant, 1,3,6 which means that the EMG activity is associated with a neuromuscular blockade and nociceptive stimuli or noxious pain as well as the hypnotic level. 3 We describe the case of a patient in whom entropy values were falsely elevated by increased EMG activity that resulted from light neuromuscular block even when the patient underwent desflurane anesthesia.…”

Section: Introductionmentioning

confidence: 99%

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Entropy values are closely related to the degree of neuromuscular block during desflurane anesthesia: a case report

Lim

Kim

et al. 2019

J Int Med Res

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The Entropy™ module and bispectral index (BIS) depth-of-anesthesia monitors have been shown to be influenced by electromyographic (EMG) activity. The increase in entropy and BIS values is most likely caused by increased EMG activity and a higher level of consciousness. A strong EMG activity can increase entropy and BIS values because it is impossible to separate electroencephalography (EEG) from EMG, and this results from their overlapping power spectra. Thus, the entropy module may be more affected by EMG compared with the BIS module because it has more overlap with the power spectra of EEG and EMG. Several studies have suggested that EMG activity is most likely to increase, especially as it relates to the level of total intravenous anesthesia without a muscle relaxant or an insufficient analgesic level, which results in falsely increased entropy values. We present the case of a patient whose entropy values were falsely elevated by increased EMG activity resulting from light neuromuscular block or nociceptive stimuli during surgery even when undergoing desflurane anesthesia. This was closely related to the change in the neuromuscular block level and it was influenced by the degree of analgesia and the remifentanil infusion rate.

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Section: Discussionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Entropy values are closely related to the degree of neuromuscular block during desflurane anesthesia: a case report

Lim

Kim

et al. 2019

J Int Med Res

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“…Pre-operative anxiety, myoclonus following etomidate, hypotension and neuromuscular blocking drugs are some factors which may affect entropy. [ 21 22 ] Two mechanisms are postulated to explain the effect of neuromuscular blockade (NMB) on entropy: The effect of NMB directly on DOA and by affecting the EMG activity indirectly. [ 5 ] This effect is seen less in deeper planes of anaesthesia.…”

Section: Discussionmentioning

confidence: 99%

Comparison of electroencephalogram entropy versus loss of verbal response to determine the requirement of propofol for induction of general anaesthesia

2015

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Background and Aims:Propofol causes dose-dependent reduction in blood pressure (BP). This study was done to evaluate the use of spectral entropy on the dose of propofol required and the haemodynamic stability during induction of general anaesthesia (GA).Methods:In this randomised controlled study, 72 American Society of Anesthesiologists’ physical status I and II patients undergoing general and orthopaedic surgeries were divided into Group S (n-36) and Group C (n-36). Patients in Group C were induced with propofol till loss of response to verbal commands and in Group S until the state entropy was <50 and state and response entropy difference was <10. The induction dose of propofol, haemodynamic parameters and the entropy values were recorded. Numerical data were expressed as a mean ± standard deviation and analysed using unpaired, two-tailed t-test. Categorical data were compared using Chi-square test. P < 0.05 value was considered significant.Results:The dose of propofol per kg was significantly more in the entropy group (1.80 ± 0.23 mg/kg in the Group C and 1.98 ± 0.217 mg/kg in the Group S [P < 0.05]). After induction, at intubation and 1 min after intubation, entropy values were lower in Group S than Group C (P < 0.05). The BP decreased significantly after induction compared with the baseline (P < 0.05), but there was no difference between the groups.Conclusion:Propofol required for induction of GA when guided by electroencephalogram entropy was significantly higher than the induction dose based on loss of verbal response. Both conventional induction and induction with entropy as the endpoint resulted in similar haemodynamic profile.

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“…However, pre-operational procedures to fix electrodes on patient's scalp are time-consuming and interpretation of EEG patterns is challenging even for experienced anaesthesiologists. Raw EEG signals are being increasingly used to monitor the depth of VIGA with sevoflurane because EEG-based indices are reported to show aberrant values [4,14,[22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Variations in Values of State, Response Entropy and Haemodynamic Parameters Associated with Development of Different Epileptiform Patterns during Volatile Induction of General Anaesthesia with Two Different Anaesthetic Regimens Using Sevoflurane in Comparison with Intravenous Induct: A Comparative Study

Stasiowski

Duława-Bułdak²,

Szumera

et al. 2020

Brain Sciences

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Background and Objectives: Raw electroencephalographic (EEG) signals are rarely used to monitor the depth of volatile induction of general anaesthesia (VIGA) with sevoflurane, even though EEG-based indices may show aberrant values. We aimed to identify whether response (RE) and state entropy (SE) variations reliably reflect the actual depth of general anaesthesia in the presence of different types of epileptiform patterns (EPs) in EEGs during induction of general anaesthesia. Materials and Methods: A randomized, prospective clinical study was performed with 60 patients receiving VIGA using sevoflurane with the increasing concentrations (group VIMA) or the vital capacity (group VCRII) technique or an intravenous single dose of propofol (group PROP). Facial electromyography (fEMG), fraction of inspired sevoflurane (FiAA), fraction of expired sevoflurane (FeAA), minimal alveolar concentration (MAC) of sevoflurane, RE and SE, and standard electroencephalographic evaluations were performed in these patients. Results: In contrast to periodic epileptiform discharges, erroneous SE and RE values in the patients’ EEGs were associated with the presence of polyspikes (PS) and rhythmic polyspikes (PSR), which were more likely to indicate toxic depth rather than false emergence from anaesthesia with no changes in the FiAA, FeAA, and MAC of sevoflurane. Conclusion: Calculated RE and SE values may be misleading during VIGA when EPs are present in patients’ EEGs. During VIGA with sevoflurane, we recommend monitoring raw EEG data in scientific studies to correlate it with potentially erroneous RE and SE values and the end-tidal concentration of sevoflurane in everyday clinical practice, when monitoring raw EEG is not available, because they can mislead anaesthesiologists to reduce sevoflurane levels in the ventilation gas and result in unintentional true emergence from anaesthesia. Further studies are required to investigate the behaviour of EEG-based indices during rapid changes in sevoflurane concentrations at different stages of VIGA and the influence of polyspikes and rhythmic polyspikes on the transformation of EEG signals into a digital form.

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Effects of etomidate on bispectral index scale and spectral entropy during induction of anesthesia by means of the raw electroencephalographic and electromyographic characteristics

Cited by 12 publications

References 17 publications

Entropy values are closely related to the degree of neuromuscular block during desflurane anesthesia: a case report

Entropy values are closely related to the degree of neuromuscular block during desflurane anesthesia: a case report

Comparison of electroencephalogram entropy versus loss of verbal response to determine the requirement of propofol for induction of general anaesthesia

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