title: Narcotrend, bispectral index, and classical electroencephalogram variables during emergence from propofol/remifentanil anesthesia.
abstract: The aim of this study was to investigate modern and classical electroencephalographic (EEG) variables in response to remifentanil and propofol infusions. We hypothesized that modern EEG variables may indicate the effects of propofol but not of remifentanil. Twenty-five patients were included in the study after the end of elective spine surgery without any surgical stimulation. Baseline values were defined with remifentanil 0.3 microg. kg(-1). min(-1) and target-controlled infusion of propofol 3.0 microg/mL. EEG changes were evaluated 1, 3, 5, 7, and 9 min after the stop of remifentanil infusion, followed by a step-by-step reduction (0.2 microg/mL) every 3 min of target-controlled infusion propofol. Narcotrend (NT; classifying EEG stages from awake to deep anesthesia), bispectral index (BIS), EEG spectral frequency bands (%), 50% (Median) and 95% percentiles (spectral edge frequency), mean arterial blood pressure, heart rate, and oxygen saturation were detected at every time point. The end of remifentanil application resulted in significant increases in %alpha, spectral edge frequency, mean arterial blood pressure, and %theta and decreases in %delta (P < 0.05). NT, BIS, Median, heart rate, and oxygen saturation were unchanged. Decreases in propofol concentration were associated with statistically significant increases in NT and BIS (P < 0.05). Thus, the sedative-hypnotic component of propofol could be estimated by modern EEG variables (NT and BIS), whereas the analgesic component provided by remifentanil was not indicated. However, during conditions without surgical stimulation, neither NT nor BIS provided an adequate assessment of the depth of anesthesia when a remifentanil infusion was used.
  
  
  CONCLUSIONS
  We investigated modern and classical electroencephalographic (EEG) variables during emergence from propofol/remifentanil anesthesia. Modern EEG variables indicate changes of infusion in propofol, but not in remifentanil. Thus, modern EEG variables did not provide an adequate assessment of depth of anesthesia when remifentanil was used.
authors.affiliation: Department of Anesthesiology, University Hospital Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany. guschmid@uke.uni-hamburg.de
authors.forename: Gunter N
authors.initials: GN
authors.lastname: Schmidt
authors.forename: Petra
authors.initials: P
authors.lastname: Bischoff
authors.forename: Thomas
authors.initials: T
authors.lastname: Standl
authors.forename: Moritz
authors.initials: M
authors.lastname: Voigt
authors.forename: Luca
authors.initials: L
authors.lastname: Papavero
authors.forename: Jochen
authors.initials: J
authors.lastname: Schulte am Esch
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000762:Anesthesia Recovery Period; D000771:Anesthesia, Intravenous; D018686:Anesthetics, Intravenous; D001794:Blood Pressure / Q000187:drug effects; D004569:Electroencephalography / Q000187:drug effects*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D010101:Oxygen Consumption / Q000187:drug effects; D010880:Piperidines; D015742:Propofol; D000077208:Remifentanil
chemical_list: D018686:Anesthetics, Intravenous; D010880:Piperidines; D000077208:Remifentanil; D015742:Propofol