We found that during both hypothermic and normothermic CPB there was an effect on hepatic perfusion and integrity by both direct ischemic effects and indirect functional impairment. In patients without underling hepatic dysfunction, the hepatocytes are usually will protected against this transient decrease in oxygen delivery and can withstand hypoxia and proinflammatory effects of CPB without major postoperative consequences in their function or integrity. The hepatic SECs which are responsible of HA uptake and metabolism, are the most sensitive hepatic cells to hypoxia and the proinflammatory effects of CPB leading to impairment of their function and elevation of serum HA level during CPB period even in patients with preoperative normal hepatic function.