ABSTRACT
BACKGROUND: Carotid endarterectomy has been proven to be beneficial for the prevention of strokes in both symptomatic and asymptomatic patients with significant carotid stenosis. Even if there is no consensus as to the most appropriate monitoring method for detecting cerebral ischemia during carotid endarterectomy, electroencephalography (EEG) and/or somatosensory evoked potential (SSEP) has been extensively used to evaluate cerebral functions. We estimated the efficacy of EEG and SSEP for detecting cerebral ischemia during carotid endarterectomy in conscious patients. METHODS: One or both of 16-channel EEG and SSEP monitoring were performed in 103 patients scheduled for carotid endarterectomy under cervical plexus block. We estimated the sensitivity and specificity of EEG and SSEP for detecting cerebral ischemia expressed by altered consciousness and shunt insertion. RESULTS: During carotid clamp in 74 cases studied, significant EEG changes were noted in 5 of the 16 patients who had cerebral ischemia, however 11 patients had no EEG changes despite cerebral ischemia. During carotid clamp in 84 cases studied, significant SSEP changes were noted in 7 of the 19 patients who had cerebral ischemia, however 12 patients had no SSEP changes despite cerebral ischemia. The sensitivity and specificity for detecting cerebral ischemia were 31% and 86% for EEG and 37% and 95% for SSEP, respectively. CONCLUSIONS: We conclude that EEG and SSEP monitoring during carotid endarterectmy under regional anesthesia is not a sensitive method for detecting cerebral ischemia.