Application of Large Volume Acute Normovolemic Hemodilution in Cardiac Surgery

Inclusion Criteria: * （1）18-75years old;（2）elective cardiac surgery under cardiopulmonary bypass; （3）Preoperative hemoglobin (Hb) ≥ 12g/dl; (4) Transfusion Risk Understanding Scoring Tool (TRUST) ≥ 2 (possibility of blood transfusion ≥40%). Exclusion Criteria: * （1）congenital heart disease、Cardiac tumor、aortic dissection、heart transplantation（2）Low body weight（\<50 kg）;（3）preoperative shock；（4）myocardial infarction within 3 months before surgery；（5）ischemic heart disease;Left main coronary artery stenosis \>70%;Severe aortic stenosis (area \< 0.7cm2);Severe changes in left ventricular function (ejection fraction \<30%, requiring vasoactive agents to assist circulation);（6）severe carotid artery stenosis (\>70% or with symptoms);（7） kidney failure (blood creatinine level \>442 mmol/L) or dialysis treatment;（8） serum albumin level (ALB) is less than 25 g/L.（9） international standardized ratio (INR) \>1.5 or platelet count \<100 103/mm3;（10）Inherited/acquired coagulation function defect;（11）contagious or infectious diseases;（12） patient or family members refused to participate in research;（13）refused to infusion of autologous blood or allogeneic blood products