Abstract]Cerebral Protection During Carotid Endarterectomy• Carotid endarterectomy was performed on 73 occasions using the following regimen during the operative period: (1) general anesthesia with normothermia, (2) maintaining a normal or slightly elevated arterial oxygen tension (Pao,, (3) maintaining a normal or low arterial carbon dioxide tension (Pco,), (4) maintaining systemic arterial pressure (SAP) at normal or slightly elevated levels, (5) employing a bypass shunt in all cases, and (6) utilizing transient systemic anticoagulation with heparin. The rationale for this regimen is explained in terms of current concepts of cerebral blood flow and metabolism. No new neurological deficit has appeared after operation using these techniques.Additional Key Words autoregulation of cerebral blood flow anticoagulation barbiturates halothane anesthesia• The goals of carotid endarterectomy are to prevent strokes and to relieve the troublesome symptomatology associated with transient cerebral ischemia. Interest in the operation has grown enormously in recent years, and several large series of patients have been reported. 1 -* As experience with the operation has accumulated, patient selection and operative indications have become more refined. As with every operation, it is important that the benefits from operation exceed the risks inherent in the procedure. If carotid endarterectomy is to be performed on patients with extracranial occlusive cerebrovascular disease who have not had strokes, then every effort must be made to prevent ischemic brain damage during the operative period.During the past four years we have incorporated some newer concepts of cerebral blood flow and metabolism into a regimen designed to protect the brain from ischemia during the operative period.' This report describes the method used on a series of patients.
MethodsPatients were selected for operation who had clinical pictures compatible with transient cerebral ischemia or a previous cerebrovascular accident from which they had recovered or that had stabilized. The presence of occlusive vascular disease at the carotid bifurcation was demonstrated by arch aortography and selective common carotid arteriography. Pancerebral angiography was performed in every case. Ophthalmodynamometry, radioisotope flow studies, brain scanning, and electroencephalography were employed when necessary for diagnosis. Using these criteria, 73 operations were performed in 62 patients over a four-year period.The regimen used to protect the brain during the operative period consisted of: (1) general anesthesia with normothermia, (2) maintaining a normal or slightly elevated Pao,, (3) maintaining a normal or low Paco,, (4) maintaining SAP at normal or slightly elevated levels, (5) employing a bypass shunt in all cases and (6) transient systemic heparinization.
ResultsSince instituting this regimen, we have had no increased neurological deficit in the immediate postoperative period. The duration of follow-up is too short to draw conclusions about the long-term effect of ...