Intra-operative variations in carotid artery blood flow and cardiac output: the effects of changes in blood volume and carbon dioxide during surgery under neurolept anesthesia.

Seven patients were operated on for stenosis of the internal carotid artery (ICA) with endarterectomy under neurolept anesthesia. The ICA blood flow was found to be unchanged after reconstruction following an operative blood loss of one fifth of the patient's blood volume despite variations in cardiac output. The relationship between carbon dioxide tension and cerebral blood flow remained unchanged during hypovolemia. It is concluded that the autoregulation of the cerebral blood flow is maintained under neurolept anesthesia.