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 (Pao2, (3) maintaining a normal or low arterial carbon dioxide tension (Pco2), (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.