For surgery of dissecting ascending aortic aneurysms we have employed deep hypothermic circulatory arrest to permit construction of the distal aortic anastomosis in a bloodless field. The cerebral complications of circulatory arrest in deep hypothermia are well recognised. Many methods of cerebral protection have been suggested besides deep hypothermia including retrograde cerebral perfusion, administration of thiopentone and cerebroplegia. We report a supplementary technique that theoretically may provide improved cerebral protection, and present the results in four cases.