title: Prediction of depth of sedation and anaesthesia by the Narcotrend EEG monitor.
abstract: BACKGROUND
  The Narcotrend (Monitor Technik, Bad Bramstedt, Germany) assesses sedation by automatic classification of EEG signals, using a scale first used for visual evaluation of the EEG. Limited information is available on its value, and only a few studies of the method exist. We set out to study the performance of the Narcotrend during propofol sedation.
  
  
  METHODS
  In 23 ASA I-II patients, aged 18-65 yr, about to have general anaesthesia, we induced anaesthesia in steps using a target-controlled infusion of propofol. After equilibration for 8 min at each predicted propofol concentration (0.5, 1.0, 2.0, 3.0 and 4.0 microg x ml(-1)), sedation was assessed clinically with the modified Observer's Assessment of Alertness/Sedation Scale and the Narcotrend stage was noted. The prediction performance of the Narcotrend was assessed with the prediction probability P(K). A P(K) value of 1.0 means an exact prediction on every occasion, while a P(K) of 0.5 is no better than a 50:50 chance of being correct.
  
  
  RESULTS
  In 12 women and 11 men (age 42 (sd 11) yr), a total of 138 measurements were made; 129 were analysed and nine were of poor signal quality. The prediction probability for the corresponding level of sedation was P(K)=0.92 (se 0.01); for the different target concentrations of propofol it was P(K) = 0.91 (se 0.01).
  
  
  CONCLUSIONS
  The Narcotrend can monitor sedation with propofol. Other sedatives, anaesthetics and opioids should be used to test this monitor.
authors.affiliation: Klinik und Poliklinik für Anästhesiologie, Universitätsklinikum Würzburg, Zentrum operative Medizin, Oberdürrbacher Strasse 6, D-97080 Würzburg, Germany. kerstinbauerle@gmx.de
authors.forename: K
authors.initials: K
authors.lastname: Bauerle
authors.forename: C-A
authors.initials: CA
authors.lastname: Greim
authors.forename: M
authors.initials: M
authors.lastname: Schroth
authors.forename: M
authors.initials: M
authors.lastname: Geisselbrecht
authors.forename: A
authors.initials: A
authors.lastname: Köbler
authors.forename: N
authors.initials: N
authors.lastname: Roewer
mesh_terms: D000328:Adult; D000771:Anesthesia, Intravenous; D018686:Anesthetics, Intravenous / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D016292:Procedural Sedation; D004305:Dose-Response Relationship, Drug; D004569:Electroencephalography / Q000187:drug effects*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000295:instrumentation* / Q000379:methods; D015742:Propofol / Q000494:pharmacology
chemical_list: D018686:Anesthetics, Intravenous; D015742:Propofol