The investigators set down the West China Transfusion Score for Critically-ill Patients(WCTS-CP) ，the initial score is 6. If a patient's cardiac output is normal without infusion of inotropic drugs, the heartbeat less than 100 per minute，his saturation of oxygen could be maintained more than 95%, his core temperature is less than 38℃, and he has no history of ischemic cardiovascular disease , and he is below 55 of age，his score is 6.