This pilot study will be done to assess the ability of the nonlinear EEG monitor (the EEGo) compared to the BIS monitor and the FORE-SIGHT cerebral oximeter to direct therapy if cerebral ischemia occurs -- notifying the surgeon of the findings, optimizing the blood pressure, arterial oxygenation and carbon dioxide tensions, and permitting consideration of placing a carotid shunt. The EEGo processes the standard EEG signal by nonlinear analysis of the raw signal by 3 dimensional phase delay plots. A cascade from a point attractor, periodic attractor, toroidal attractor to a 3D chaotic attractor occurs from burst suppression to the awake state. These resemble phase transitions and occur rapidly from one state to the next. An analogy is the phase transition that occurs when water changes to ice and vice versa. Monitoring these transitions should permit a rational approach to monitoring cerebral well-being during carotid cross-clamping with CEA. The EEGo will be compared directly in real time to the bispectral (BIS) monitor and to the FORE-SIGHT cerebral oximeter for intraoperative monitoring during CEA.