Effect of Cafedrine/Theodrenaline and Urapidil on Cerebral Oxygenation (NIRSMED)

During clamping of one internal carotid artery for endarterectomy, blood flow through this vessel has to be compensated by collateral arteries including the contralateral internal artery and vertebral arteries. In 7 % of all patients undergoing carotid endarterectomy this collateral flow is not sufficient to maintain adequate cerebral perfusion during clamping and ischemic brain damage is likely to emerge. To maximize cerebral blood flow during clamping, increase of blood pressure is a common procedure and routine at our institution. Increasing blood pressure can be enabled by tapering a mixture of Cafedrine und Theodrenalin (Akrinor®) until the designated blood pressure is reached. After declamping, the blood pressure has to be reduced to normal values to avoid postoperative hyperperfusion syndrome. This is enabled by tapering urapidil until normal blood pressure is achieved.

It has been shown that cerebral oxygenation measured by near infrared spectroscopy is reduced by intravenous application of norepinephrine. Otherwise, intravenous nitroglycerine increases cerebral oxygenation during cardiopulmonary bypass. Hence, cafedrine/theodrenalin and urapidil may also have an effect on cerebral perfusion. In this prospective randomized study the effect of cafedrine/theodrenalin and urapidil on cerebral oxygenation measured by near infrared spectroscopy is investigated.