Correlation of Approximate Entropy, Bispectral Index, and Spectral Edge Frequency 95 (SEF95) with Clinical Signs of “Anesthetic Depth” during Coadministration of Propofol and Remifentanil

Background Several studies relating electroencephalogram parameter values to clinical endpoints using a single (mostly hypnotic) drug at relatively low levels of central nervous system depression (sedation) have been published. However, the usefulness of a parameter derived from the electroencephalogram for clinical anesthesia largely depends on its ability to predict the response to stimuli of different intensity or painfulness under a combination of a hypnotic and an (opioid) analgesic. This study was designed to evaluate the predictive performance of spectral edge frequency 95 (SEF95), BIS, and approximate entropy for the response to increasingly intense stimuli under different concentrations of both propofol and remifentanil in the therapeutic range. Methods Ten healthy male and ten healthy female volunteers were studied during coadministration of propofol and remifentanil. After having maintained a specific target concentration for 10 min, the depth of sedation-anesthesia was assessed using the responsiveness component of the Observer's Assessment of Alertness/Sedation (OAA/S) rating scale, which was modified by adding insertion of a laryngeal mask and laryngoscopy. The electroencephalogram derived parameters approximate entropy, bispectral index, and SEF95 were recorded just before sedation level was assessed. Results The prediction probability values for approximate entropy were slightly, but not significantly, better than those for bispectral index, SEF95, and the combination of drug concentrations. A much lower prediction ability was observed for tolerance of airway manipulation than for hypnotic endpoints. Conclusion Approximate entropy revealed informations on hypnotic and analgesic endpoints using coadministration of propofol and remifentanil comparable to bispectral index, SEF95, and the combination of drug concentrations.

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Approximate Entropy as an Electroencephalographic Measure of Anesthetic Drug Effect during Desflurane Anesthesia

Anesthesiology ◽

10.1097/00000542-200003000-00016 ◽

2000 ◽

Vol 92 (3) ◽

pp. 715-726 ◽

Cited By ~ 226

Author(s):

Jörgen Bruhn ◽

Heiko Röpcke ◽

Andreas Hoeft

Keyword(s):

Bispectral Index ◽

Drug Effect ◽

Statistical Parameter ◽

Approximate Entropy ◽

Pharmacodynamic Modeling ◽

Median Frequency ◽

Anesthetic Drug ◽

Spectral Edge Frequency ◽

Spectral Edge ◽

Prediction Probability

Background The authors hypothesized that the electroencephalogram (EEG) during higher anesthetic concentrations would show more "order" and less "randomness" than at lower anesthetic concentrations. "Approximate entropy" is a new statistical parameter derived from the Kolmogorov-Sinai entropy formula which quantifies the amount of regularity in data. The approximate entropy quantifies the predictability of subsequent amplitude values of the EEG based on the knowledge of the previous amplitude values. The authors investigated the dose-response relation of the EEG approximate entropy during desflurane anesthesia in comparison with spectral edge frequency 95, median frequency, and bispectral index. Methods Twelve female patients were studied during gynecologic laparotomies. Between opening and closure of the peritoneum, end-tidal desflurane concentrations were varied between 0.5 and 1.6 minimum alveolar concentration (MAC). The EEG approximate entropy, median EEG frequency, spectral edge frequency 95, and bispectral index were determined and the performance of each to predict the desflurane effect compartment concentration, obtained by simultaneous pharmacokinetic-pharmacodynamic modeling, was compared. Results Electroencephalogram approximate entropy decreased continuously over the observed concentration range of desflurane. The performance of the approximate entropy (prediction probability PK = 0.86 +/- 0.06) as an indicator for desflurane concentrations is similar to spectral edge frequency 95 (PK = 0.86 +/- 0.06) and bispectral index (PK = 0.82 +/- 0.06) and is statistically significantly better than median frequency (PK = 0.78 +/- 0.06). Conclusions The amount of regularity in the EEG increases with increasing desflurane concentrations. The approximate entropy could be a useful EEG measure of anesthetic drug effect.

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Electroencephalographic Approximate Entropy Changes in Healthy Volunteers during Remifentanil Infusion

Anesthesiology ◽

10.1097/00000542-200605000-00006 ◽

2006 ◽

Vol 104 (5) ◽

pp. 921-932 ◽

Cited By ~ 31

Author(s):

Gyu-Jeong Noh ◽

Kye-Min Kim ◽

Yong-Bo Jeong ◽

Seong-Wook Jeong ◽

Hee-Suk Yoon ◽

...

Keyword(s):

Healthy Volunteers ◽

Signal To Noise Ratio ◽

Approximate Entropy ◽

Signal To Noise ◽

Spectral Edge Frequency ◽

Spectral Edge ◽

Median Baseline ◽

Coefficients Of Variation ◽

Prediction Probability ◽

Noise Ratio

Background The aim of this study was to investigate the independent effect of remifentanil on the approximate entropy (ApEn) in frontoparietal montages. The authors investigated which montages were relevant to assess the remifentanil effect on the electroencephalogram. Spectral edge frequency and the canonical univariate parameter were used as comparators. Methods Twenty-eight healthy volunteers were enrolled. With recording of the electroencephalogram at the F3, F4, Cz, P3, and P4 montages, remifentanil was infused at the rate of 1-8 mug . kg . min for 15-20 min. The relation between remifentanil concentration and the electroencephalographic parameters were tested by Spearman correlation. Signal-to-noise ratio, artifact robustness, coefficient of variation of the median baseline and maximal electroencephalographic effects, and ratio of average maximal electroencephalographic effect to interindividual baseline variability were measured. The performance of ApEn as an index of remifentanil effect site concentrations was tested by prediction probability. Results Approximate entropy showed significant correlation (R = -0.6465, P < 0.0001) with remifentanil concentration. It provided comparable signal-to-noise ratio, artifact robustness, and ratio of average maximal electroencephalographic effect to interindividual baseline variability to 95% spectral edge frequency. The coefficients of variation of the median baseline and maximal electroencephalo graphic effects were smallest in ApEn. Parietal montages showed higher ratios of average maximal electroencephalographic effect to interindividual baseline variability for all electroencephalographic parameters and lower coefficients of variation of the baseline values for ApEn and 95% spectral edge frequency than frontal montages. The prediction probability of ApEn was 0.7730. Conclusions Approximate entropy derived from a parietal montage is appropriate for the assessment of the remifentanil effect on the electroencephalogram.

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Median Frequency Revisited

Anesthesiology ◽

10.1097/01.anes.0000278904.63884.4c ◽

2007 ◽

Vol 107 (3) ◽

pp. 397-405 ◽

Cited By ~ 14

Author(s):

Denis Jordan ◽

Gudrun Stockmanns ◽

Eberhard F. Kochs ◽

Gerhard Schneider

Keyword(s):

Spectral Parameter ◽

Bispectral Index ◽

Median Frequency ◽

Spectral Parameters ◽

Data Set ◽

Spectral Edge Frequency ◽

Spectral Edge ◽

Prediction Probability ◽

Hypnotic Agent ◽

The Fourier Transform

Background In the past, several electroencephalographic parameters have been presented and discussed with regard to their reliability in discerning consciousness from unconsciousness. Some of them, such as the median frequency and spectral edge frequency, are based on classic spectral analysis, and it has been demonstrated that they are of limited capacity in differing consciousness and unconsciousness. Methods A generalized approach based on the Fourier transform is presented to improve the performance of electroencephalographic parameters with respect to the separation of consciousness from unconsciousness. Electroencephalographic data from two similar clinical studies (for parameter development and evaluation) in adult patients undergoing general anesthesia with sevoflurane or propofol are used. The study period was from induction of anesthesia until patients followed command after surgery and includes a reduction of the hypnotic agent after tracheal intubation until patients followed command. Prediction probability was calculated to assess the ability of the parameters to separate consciousness from unconsciousness. Results On the basis of the training set of 40 patients, a new spectral parameter called weighted spectral median frequency was designed, achieving a prediction probability of 0.82 on the basis of the "classic" electroencephalographic frequency range up to 30 Hz. Next, in the evaluation data set, the prediction probability was 0.79, which is higher than the prediction probability of median frequency (0.58) or spectral edge frequency (0.59) and the Bispectral Index (0.68) as calculated from the same data set. Conclusions A more general approach of the design of spectral parameters leads to a new electroencephalographic spectral parameter that separates consciousness from unconsciousness significantly better than the Bispectral Index.

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Concentration–Effect Relations, Prediction Probabilities (Pk), and Signal-to-noise Ratios of Different Electroencephalographic Parameters during Administration of Desflurane, Isoflurane, and Sevoflurane in Rats

Anesthesiology ◽

10.1097/01.anes.0000300074.04200.b1 ◽

2008 ◽

Vol 108 (2) ◽

pp. 276-285 ◽

Cited By ~ 13

Author(s):

Harald Ihmsen ◽

Michael Schywalsky ◽

Regina Plettke ◽

Michael Priller ◽

Florian Walz ◽

...

Keyword(s):

Approximate Entropy ◽

Burst Suppression ◽

Concentration Effect ◽

Median Frequency ◽

Sprague Dawley ◽

Signal To Noise ◽

Spectral Edge Frequency ◽

Spectral Edge ◽

Anesthetic Effect ◽

Prediction Probability

Background The authors investigated the suitability of different electroencephalographic parameters to quantify the anesthetic effect of desflurane, isoflurane, and sevoflurane in rats. Methods Ten male Sprague-Dawley rats were anesthetized in a randomized crossover design with maximum values of 11% desflurane, 2.1% isoflurane, and 3.5% sevoflurane. The electroencephalogram was recorded with implanted electrodes and a wireless telemetry system. Concentration-effect relations and signal-to-noise ratios were determined for the approximate entropy and for the median frequency and the spectral edge frequency, which were modified to account for spikes and burst suppression. The prediction probability Pk with respect to the response to a painful stimulus was determined. Results All drugs produced deep anesthesia with burst suppression and no response at the highest concentrations. The occurrence of spikes and burst suppression made a modification of median frequency and spectral edge frequency necessary to obtain Pk values greater than 0.5 and monotonic sigmoid concentration-effect relations. The Pk values were between 0.89 and 0.98, with significantly higher values for modified median frequency and spectral edge frequency during desflurane and sevoflurane. The signal-to-noise ratios were between 3.0 and 6.4 dB, with significantly better values for modified spectral edge frequency and approximate entropy during sevoflurane. Conclusions If modified for spikes and burst suppression, median frequency and spectral edge frequency as well as the unmodified approximate entropy were able to assess the anesthetic effect of desflurane, isoflurane, and sevoflurane in rats. For sevoflurane, the modified spectral edge frequency was best with regard to signal-to-noise ratio and prediction probability.

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Comparison of bispectral index, 95% spectral edge frequency and approximate entropy of the EEG, with changes in heart rate variability during induction of general anaesthesia

British Journal of Anaesthesia ◽

10.1093/bja/82.5.666 ◽

1999 ◽

Vol 82 (5) ◽

pp. 666-671 ◽

Cited By ~ 95

Author(s):

J W Sleigh ◽

J Donovan

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

General Anaesthesia ◽

Bispectral Index ◽

Approximate Entropy ◽

Spectral Edge Frequency ◽

Spectral Edge

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Narcotrend® and Bispectral Index® Monitor Are Superior to Classic Electroencephalographic Parameters for the Assessment of Anesthetic States during Propofol-Remifentanil Anesthesia

Anesthesiology ◽

10.1097/00000542-200311000-00012 ◽

2003 ◽

Vol 99 (5) ◽

pp. 1072-1077 ◽

Cited By ~ 42

Author(s):

Gunter N. Schmidt ◽

Petra Bischoff ◽

Thomas Standl ◽

Kai Jensen ◽

Moritz Voigt ◽

...

Keyword(s):

Steady State ◽

Clinical Assessment ◽

Bispectral Index ◽

Median Frequency ◽

Relative Power ◽

Hemodynamic Parameters ◽

Anesthetic Depth ◽

Spectral Edge Frequency ◽

Spectral Edge ◽

Prediction Probability

Background A new electroencephalogram monitor, the Narcotrend, was developed to measure anesthetic depth. The authors compared the Narcotrend, the Bispectral Index, and classic electroencephalographic and hemodynamic parameters during anesthesia with propofol and remifentanil. Methods The authors investigated 25 patients undergoing laminectomy at different anesthetic states: awake, steady state anesthesia, first reaction during emergence, and extubation. Narcotrend value; BIS; relative power (percent) in delta, theta, alpha, and beta; median frequency; spectral edge frequency; and hemodynamic parameters were recorded simultaneously. The ability of the classic and processed electroencephalographic and hemodynamic parameters to predict the clinically relevant anesthetic states of awake, steady state anesthesia, first reaction, and extubation was tested using prediction probability. Results Only the Narcotrend was able to differentiate between awake versus steady state anesthesia and steady state anesthesia versus first reaction/extubation with a prediction probability value of more than 0.90. Conclusions Modern electroencephalographic parameters, especially Narcotrend, are more reliable indicators for the clinical assessment of anesthetic states than classic parameters.

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Comparative Evaluation of a New Depth of Anesthesia Index in ConView® System and the Bispectral Index during Total Intravenous Anesthesia: A Multicenter Clinical Trial

BioMed Research International ◽

10.1155/2019/1014825 ◽

2019 ◽

Vol 2019 ◽

pp. 1-7

Author(s):

Yang Fu ◽

Tao Xu ◽

Keliang Xie ◽

Wei Wei ◽

Ping Gao ◽

...

Keyword(s):

Clinical Trial ◽

Bispectral Index ◽

Mean Value ◽

Total Intravenous Anesthesia ◽

Depth Of Anesthesia ◽

Clinical Trial Registry ◽

Intravenous Anesthesia ◽

Spectral Edge Frequency ◽

Prediction Probability ◽

Conscious Level

The performance of a new monitor for the depth of anesthesia (DOA), the Depth of Anesthesia Index (Ai) based on sample entropy (SampEn), 95% spectral edge frequency (95%SEF), and burst suppression ratio (BSR) was evaluated compared to Bispectral Index (BIS) during total intravenous anesthesia (TIVA). 144 patients in six medical centers were enrolled. General anesthesia was induced with stepwise-increased target-controlled infusion (TCI) of propofol until loss of consciousness (LOC). During surgery propofol was titrated according to BIS. Both Ai and BIS were recorded. Primary outcomes: the limits of agreement between Ai and BIS were -17.68 and 16.49, which were, respectively, -30.0% and 28.0% of the mean value of BIS. Secondary outcomes: prediction probability (Pk) of BIS and Ai was 0.943 and 0.935 (p=0.102) during LOC and 0.928 and 0.918 (p=0.037) during recovery of consciousness (ROC). And the values of BIS and Ai were 68.19 and 66.44 at 50%LOC, and 76.65 and 78.60 at 50%ROC. A decrease or an increase of Ai was significantly greater than that of BIS when consciousness changes (during LOC: -9.13±10.20 versus -5.83±9.63, p<0.001; during ROC: 10.88±11.51 versus 5.32±7.53, p<0.001). The conclusion is that Ai has similar characteristic of BIS as a DOA monitor and revealed the advantage of SampEn for indicating conscious level. This trial is registered at Chinese Clinical Trial Registry with ChiCTR-IOR-16009471.

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