EARTERECTOMY for stenotic lesions of the carotid arteries provides effective relief of cerebrovascular insufficiency and prevents the development of stroke in patients with extracranial vascular disease.1 Segmental vascular occlusive disease occurs in the region of the carotid artery bifurcation in many patients with various clinical syndromes of cerebrovascular insufficiency. On the basis of onset, extent of involvement, and persistence of neurologic deficits, these syndromes are classified into transient ischemic attacks, persistent progressive symptoms of stroke, acute completed stroke, and chronic completed stroke. Patients in these categories with occlusive carotid artery disease, as well as certain patients free of neurologic symptoms but with stenotic lesions demonstrated by arteriography, are subjected to an operation to remove the obstructing atherosclerotic lesions. At our institutions a technique was introduced for performing carotid endarterectomy in which general anesthesia with deliberate hypercarbia was employed to increase cerebral blood flow.2 Use of this technique obviates