title: [Bispectral index, cerebral state index and the predicted effect-site concentration at different clinical end-points during target-controlled infusion of propofol].
abstract: OBJECTIVE
  To examine the predicted effect-site concentration of propofol at two clinical end-points: loss of verbal contact (LVC) and loss of consciousness (LOC), and to explore the relationship between bispectral index (BIS) values, cerebral state index (CSI) values and the predicted effect-site concentration during the target-controlled infusion of propofol.
  
  
  METHODS
  In 20 patients during the target-controlled infusion of propofol, the propofol infusion was set at an initial effect-site concentration of 0.5 mg/L, and increased by 0.5 mg/L every 5 min until 5 min after the modified observer's assessment of alertness/sedation scale (OAA/S) values reached zero. The predicted effect-site concentration of propofol, the values of CSI and BIS were recorded, and the sedation level was examined by the modified OAA/S every 20s. The predicted effect-site concentrations of propofol in target-controlled infusion (TCI) system were recorded when they increased by more than 0.1 mg/L. The predicted effect-site concentrations of propofol and the values of BIS and CSI at LVC and LOC in 5%, 50% and 95% of the patients were calculated.
  
  
  RESULTS
  There was good linearity between BIS and the predicted effect-site concentration of propofol (R(2)=0.787), as well as between CSI and the predicted effect-site concentration of propofol (R(2)=0.792). The predicted effect-site concentrations of propofol at LVC in 5%, 50% and 95% of the patients were 1.1,1.8 and 2.4 mg/L, respectively. The values of BIS and CSI at LVC in 5%, 50% and 95% of the patients were 79.2, 69.2 and 59.2; 74.9, 65.9 and 56.8, respectively. The predicted effect-site concentrations of propofol at LOC in 5%, 50% and 95% of the patients were 1.5, 2.5 and 3.4 mg/L, respectively. At LOC, the values of BIS and CSI in 5%, 50% and 95% of the patient were 73.6, 57.1 and 40.6; 65.2, 54.8 and 44.3, respectively.
  
  
  CONCLUSIONS
  During target-controlled infusion of propofol, LVC and LOC occur within a definite range of predicted effect-site concentrations. There is the good linearity between BIS, CSI and the predicted effect-site concentrations of propofol. CSI may be more useful than BIS in predicting LVC and LOC.
authors.affiliation: Department of Anesthesiology, Xiangya Hospital, Central South University, Changsha 410008, China.
authors.forename: Sheng-hui
authors.initials: SH
authors.lastname: Yang
authors.forename: Tao
authors.initials: T
authors.lastname: Zhong
authors.forename: Qu-lian
authors.initials: QL
authors.lastname: Guo
authors.forename: Yun-dan
authors.initials: YD
authors.lastname: Pan
mesh_terms: D000328:Adult; D018686:Anesthetics, Intravenous / Q000008:administration & dosage* / Q000494:pharmacology; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D016343:Monitoring, Intraoperative; D015742:Propofol / Q000008:administration & dosage* / Q000494:pharmacology
chemical_list: D018686:Anesthetics, Intravenous; D015742:Propofol