Bispectral index changes in carotid surgery
M J Estruch-Pérez1, A Ausina-Aguilar, M Barberá-Alacreu
1Anesthesiology and Critical Care Department, Dr. Peset University Hospital, and Department of Preventive Medicine, University of Valencia, Valencia, Spain. estruch_mar@gva.es
Annals of Vascular Surgery
|November 26, 2009
Summary
Bispectral index (BIS) monitoring during carotid clamping effectively identifies cerebral ischemia in carotid endarterectomy (CEA) patients. A BIS decrease of 14% or more suggests ischemia is unlikely, aiding intraoperative decision-making.
Area of Science:
- Anesthesiology
- Neurosurgery
- Neurology
Background:
- Intraoperative monitoring for cerebral ischemia during carotid endarterectomy (CEA) using shunting is debated.
- Evaluating the sensitivity and specificity of bispectral index (BIS) changes during carotid clamping is crucial for awake CEA.
Purpose of the Study:
- To assess BIS changes during carotid clamping in relation to shunting in awake CEA patients.
- To determine the diagnostic accuracy of BIS monitoring for detecting cerebral ischemia.
Main Methods:
- Eighty CEAs under cervical block were analyzed, comparing shunted (ischemia signs) and nonshunted patients.
- BIS values and neurological monitoring were recorded, focusing on carotid clamping.
- Sensitivity, specificity, and predictive values of BIS decrease during clamping were calculated.
Main Results:
- Shunting was required in 11 patients due to cerebral ischemia.
- Mean BIS values were significantly lower in shunted (82.82) versus nonshunted (92.31) patients during clamping (p<0.001).
- A BIS decrease of >=14% showed 81.8% sensitivity and 89.7% specificity for detecting cerebral ischemia.
Conclusions:
- BIS monitoring is a simple, noninvasive tool for detecting cerebral ischemia during CEA.
- A BIS decrease >=14% has a high negative predictive value, indicating ischemia is unlikely without it.
- However, a BIS decrease has a low positive predictive value, not always confirming ischemia.
