title: Can the cerebral state monitor replace the bispectral index in monitoring hypnotic effect during propofol/remifentanil anaesthesia?
abstract: BACKGROUND
  In 2004, the cerebral state monitor, CSM, was launched as a low-cost alternative to the bispectral index, BIS, for monitoring depth of sleep during anaesthesia. We tested whether the two monitors would reflect hypnosis equally during propofol/remifentanil anaesthesia.
  
  
  METHODS
  During laparoscopy or breast/surface surgery, 55 non-paralyzed patients were monitored simultaneously with the BIS and the CSM. Trend curves for the indexes [BIS and cerebral state index (CSI)] were compared for congruence. The difference between the two indexes for the entire course was quantified, and the ability of the two monitors to separate awake from asleep during induction was described.
  
  
  RESULTS
  In the majority of the patients, 87%, there was a good fit between the indexes. There were major deviations in seven patients, in whom CSI indicated that the patients were awake during parts of the course despite clinical sleep, correctly identified with the BIS. Both indexes separated awake from asleep during induction in the individual patient, but the overlap in values between patients was more pronounced for CSI.
  
  
  CONCLUSIONS
  CSM and BIS show some important differences in measuring hypnotic state during clinical propofol/remifentanil anaesthesia.
authors.affiliation: Department of Anaesthesia, Ullevaal University Hospital and University of Oslo, Faculty Division of Ullevaal University Hospital, Oslo, Norway. s.c.hoymork@medisin.uio.no
authors.forename: S C
authors.initials: SC
authors.lastname: Hoymork
authors.forename: K
authors.initials: K
authors.lastname: Hval
authors.forename: E W
authors.initials: EW
authors.lastname: Jensen
authors.forename: J
authors.initials: J
authors.lastname: Raeder
mesh_terms: D000328:Adult; D000758:Anesthesia; D000768:Anesthesia, General; D019162:Anesthetics, Combined; D018686:Anesthetics, Intravenous; D016265:Conflict of Interest / Q000331:legislation & jurisprudence; D004569:Electroencephalography / Q000295:instrumentation* / Q000379:methods; D005260:Female; D006801:Humans; D006991:Hypnosis, Anesthetic / Q000145:classification / Q000523:psychology; D008297:Male; D016343:Monitoring, Intraoperative / Q000295:instrumentation* / Q000379:methods; D010880:Piperidines; D015742:Propofol; D000077208:Remifentanil
chemical_list: D019162:Anesthetics, Combined; D018686:Anesthetics, Intravenous; D010880:Piperidines; D000077208:Remifentanil; D015742:Propofol