title: The utility of using the bispectral index-Vista for detecting cross-clamping decline in cerebral blood flow velocity.
abstract: BACKGROUND
  Patients undergoing carotid endarterectomy for extracranial internal carotid artery stenosis are at risk of cerebral ischemia/hypoperfusion. Criterion recommended by European and American committees to determine whether to place a shunt consisted of a decline in transcranial Doppler ultrasonography-measured middle cerebral artery blood flow velocity (MCBFV) to < 30% to 40% of intraoperative preclamp value.
  
  
  OBJECTIVE
  To assess the discriminative power of the bispectral index (BIS)-Vista monitor for detecting a 40% decline in MCBFV with cross-clamping.
  
  
  METHODS
  In 20 patients undergoing carotid endarterectomy under remifentanil/propofol anesthesia, BIS-Vista data, MCBFV, and pulsatility index from bilaterally mounted BIS-Vista and transcranial Doppler monitors were continuously recorded.
  
  
  RESULTS
  Coefficient of determination revealed good correlation (r = 0.763) between ipsilateral BIS-Vista and MCBFV after cross-clamping. BIS-Vista exhibited a high discriminative power of 0.850 (95% confidence interval, 0.455-0.966) area under the receiver-operating characteristic curve in detecting an ipsilateral 40% MCBFV decline. Two-way analysis of variance (location by time) suggests that BIS-Vista exhibited a global decline; ie, both BIS-Vistas declined when 1 carotid on either side was clamped because there was no significant interhemispheric difference (P = .112) in mean BIS-Vista values over time.
  
  
  CONCLUSIONS
  Although we demonstrated good correlation and high discriminative power of the BIS-Vista monitor in depicting a MCBFV decline that could serve as indicator of decline in cerebral activity, BIS-Vista cannot be considered a reliable indicator of cerebral ischemia/hypoperfusion that could replace transcranial Doppler monitoring to determine whether a shunt is to be placed.
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, Medical University of Graz, Graz, Austria.
authors.forename: Ashraf A
authors.initials: AA
authors.lastname: Dahaba
authors.forename: Ji Xiu
authors.initials: JX
authors.lastname: Xue
authors.forename: Yang
authors.initials: Y
authors.lastname: Hua
authors.forename: Qing Hai
authors.initials: QH
authors.lastname: Liu
authors.forename: Guo Xun
authors.initials: GX
authors.lastname: Xu
authors.forename: Yu Mei
authors.initials: YM
authors.lastname: Liu
authors.forename: Xiu Feng
authors.initials: XF
authors.lastname: Meng
authors.forename: Guo Guang
authors.initials: GG
authors.lastname: Zhao
authors.forename: Peter H
authors.initials: PH
authors.lastname: Rehak
authors.forename: Helfried
authors.initials: H
authors.lastname: Metzler
mesh_terms: D000368:Aged; D000465:Algorithms; D001776:Blood Circulation Time / Q000379:methods; D001783:Blood Flow Velocity / Q000502:physiology; D016893:Carotid Stenosis / Q000503:physiopathology* / Q000601:surgery*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods; D004576:Electromyography; D016894:Endarterectomy, Carotid / Q000379:methods*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D020768:Middle Cerebral Artery / Q000503:physiopathology; D016343:Monitoring, Intraoperative / Q000379:methods*; D012372:ROC Curve; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods