Objective:To compare the cerebral protective effect of conventional and hyperoxia management strategy during deep hypothermia in patients with DeBake type 1 aortic dissection or aortic arch aneurysm undergoing total aortic arch replacement.Methods:From June 2003 to July 2005,32 adult patients undergoing total aortic arch replacement were randomly allocated to one of two groups (n=16 each):conventional (C) and hyperoxia group (H).The patients had no history of cerebral vascular disease.Left radial artery and dorsal artery of left foot were cannulated for monitoring of blood pressure.