The Narcotrend Index: classification algorithm, correlation with propofol effect-site concentrations, and comparison with spectral parameters.
A reliable assessment of the depth of hypnosis during sedation and general anaesthesia using the EEG is a subject of current interest. The Narcotrend Index implemented in the latest version 4.0 of the EEG monitor Narcotrend provides an automatic classification of the EEG on a scale ranging from 100 (awake) to 0 (very deep hypnosis, EEG suppression). The classification algorithms implemented in the EEG monitor Narcotrend are described. In a study the correlation of the propofol effect-site concentration with the Narcotrend Index and with the traditional spectral parameters total power, relative power in the standard frequency bands delta, theta, alpha, and beta, median frequency, 95% spectral edge frequency, burst-compensated spectral edge frequency, and spectral entropy was investigated. The Narcotrend Index had the highest average correlation with the propofol effect-site concentration and the smallest variability of the individual correlation values. Moreover, the Narcotrend Index was the only parameter which showed a monophasic trend over the whole investigated time period. The Narcotrend monitor can make a significant contribution to the improvement of the quality of anaesthesia by adjusting the dosage of hypnotics to individual patient needs.
Schultz
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Arbeitsgruppe Informatik/Biometrie der Anästhesie, Klinikum Hannover Oststadt, Medizinische Hochschule Hannover, Germany. AB.Schultz@t-online.de
Grouven
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Beger
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Schultz
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D000293:Adolescent; D000328:Adult; D000368:Aged; D000768:Anesthesia, General; D018686:Anesthetics, Intravenous / Q000493:pharmacokinetics; D002540:Cerebral Cortex / Q000187:drug effects / Q000503:physiopathology; D016292:Procedural Sedation; D004569:Electroencephalography / Q000145:classification* / Q000187:drug effects; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology; D005260:Female; D005583:Fourier Analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D010880:Piperidines; D015742:Propofol / Q000493:pharmacokinetics; D000077208:Remifentanil; D012815:Signal Processing, Computer-Assisted
D018686:Anesthetics, Intravenous; D010880:Piperidines; D000077208:Remifentanil; D015742:Propofol