Carotid endarterectomy is a prophylactic operation, and involves removal of an atheromatous lesion of the carotid artery that is likely to lead to a future stroke if left alone. However, patients who might benefit from carotid endarterectomy also have high levels of coronary artery disease, and the operation carries a significant morbidity and mortality from stroke and myocardial infarction. Of prime concern during carotid endarterectomy is protection of the brain during carotid cross-clamping. For a patient under general anaesthesia, this is a considerable problem and various techniques have been used to detect inadequate cerebral perfusion, including the use of: carotid artery stump pressure measurement. Electroencephalograph (EEG) processing, somatosensory evoked potentials transcranial Doppler of the middle cerebral artery near infrared spectroscopy. And combinations of some of these techniques. Unfortunately, all of these methods have relatively poor sensitivity and specificity in detecting inadequate cerebral perfusion. Proponents of regional anaesthesia claim other advantages apart from ease of monitoring cerebral perfusion, including: lower requirement for shunting lower cardiovascular morbidity shorter ICU and hospital stay . Less expense overall than general anaesthesia Carotid endarterectomy under regional anaesthesia requires block of the second (C2), third (C3) and perhaps the fourth (C4) cervical dermatomes which may be accomplished in several different ways.