title: Comparison of electroencephalography and cerebral oximetry to determine the need for in-line arterial shunting in patients undergoing carotid endarterectomy.
abstract: OBJECTIVE
  To compare cerebral near-infrared regional spectroscopy (NIRS) with the 12-lead electroencephalogram for the detection of ischemia during carotid artery clamping for carotid endarterectomy (CEA).
  
  
  METHODS
  Prospective, observational.
  
  
  METHODS
  Single, tertiary care center.
  
  
  METHODS
  Ninety patients older than 18 undergoing elective, unilateral CEA.
  
  
  METHODS
  In addition to EEG monitoring, all patients underwent continuous blinded NIRS monitoring with sensors placed bilaterally above the supraorbital ridge.
  
  
  RESULTS
  Seventeen patients were excluded, leaving 73 patients available for evaluation. Four patients (5.5%) required shunting based on EEG findings. Changes in cerebral oxygen saturation (rSO2) were assessed on the operative side using the average value for the 1 minute prior to cross-clamp and the lowest rSO2 value the first 5 minutes postclamp. Each 1% absolute decrease and each 1% relative decrease from baseline conferred a 50% increase in the need for shunt placement (OR 1.5; 95% CI (1.03-2.26); p = 0.03 and OR 1.4; 95% CI (1.02-1.81); p = 0.04 respectively). Sensitivity, specificity, and positive and negative predictive values were determined using significant cutoffs of≥5% absolute change or≥10% relative change. Positive predictive value was low (<25%) for both absolute and relative changes.
  
  
  CONCLUSIONS
  A decrease in rSO2 during carotid cross-clamping for CEA is associated with EEG-determined need for shunting, but the positive predictive value is low. Using the above cutoffs in the current series would have resulted in an increase in the shunt rate by approximately 20% when it was not indicated by EEG.
authors.affiliation: Departments of Anesthesiology. Electronic address: mauermann.william@mayo.edu.
authors.forename: William J
authors.initials: WJ
authors.lastname: Mauermann
authors.forename: Amy Z
authors.initials: AZ
authors.lastname: Crepeau
authors.forename: Juan N
authors.initials: JN
authors.lastname: Pulido
authors.forename: James J
authors.initials: JJ
authors.lastname: Lynch
authors.forename: Aaron
authors.initials: A
authors.lastname: Lobbestael
authors.forename: Gustavo S
authors.initials: GS
authors.lastname: Oderich
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Worrell
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003250:Constriction; D004562:Electrocardiography; D004569:Electroencephalography / Q000379:methods*; D016894:Endarterectomy, Carotid / Q000379:methods*; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007511:Ischemia / Q000209:etiology / Q000517:prevention & control; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D016017:Odds Ratio; D010092:Oximetry / Q000379:methods*; D010101:Oxygen Consumption / Q000502:physiology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D019265:Spectroscopy, Near-Infrared; D062666:Vascular Access Devices
keywords: anesthesia; carotid endarterectomy; cerebral oximetry; electroencephalography; noninvasive regional spectroscopy; shunting; stroke