Correlation of cerebral oximetry with internal carotid artery stump pressures in carotid endarterectomy

Objective: This study compares internal carotid artery (ICA) mean stump pressures (SPs) with cerebral oximetry monitoring during carotid endarterectomy (CEA). Methods: A total of 104 consecutive patients undergoing CEA under general anesthesia (GA) during a 10-month period were prospectively evaluated. Baseline and postcarotid clamp regional cerebral oxygen saturation (rSO₂) and mean ICA SPs were measured. Demographic, surgical, and medical variables were recorded for each case. Results: There were no postoperative strokes. Thirteen patients were excluded because of incomplete data. Of the 40 patients who had <10% drop in rSO₂, 6 had SP <40 mm Hg. Regional cerebral oxygen saturation with a 15% saturation drop threshold was 76.3% sensitive and 81.1% specific in detecting patients with SP <40 mm Hg. With a threshold of 20% drop, sensitivity and specificity were 57.9% and 86.8%, respectively. Conclusions: Relative drop in rSO₂ is neither sensitive nor specific in detecting patients with mean SP <40 mm Hg. These data do not support the use of cerebral oximetry as the sole monitoring modality during carotid endarterectomy under GA.