Abstract: Objective To explore the impact of erythrocyte storage duration on blood indexes in children with-open heart surgery by cardiopulmonary bypass（CPB）,and providing laboratory basis for the safety of clinical blood transfusion. Methods A total of 90 consecutive pediatric patients from January 2019 to July 2020 who received the open heart surgery by CPB in our hospital were retrospectively studied. They were divided into the fresher blood group（≤14 d,n=49）and the older blood group（14~35 d,n=41） according to the erythrocyte storage duration. The CRP,blood routine,blood electrolyte level, renal function,myocardial enzymes and coagulation function were collected and their differences were compared between the two groups after 48 hours of surgery. Results After surgery,there were no significant difference between the two groups in the changes of the CRP level,the count of WBC,the HGB level,the count of PLT ,the K⁺, Na⁺,CL^- and Ca²⁺ level,the CO₂,BUN,Cr and UA level,the AST,LDH,CK,CK-MB and α-HBDH level before and after surgery（P>0.05）. There was no significant difference in the changes of PT,INR and FIB between the two groups （P>0.05）,but the APTT changes in the older blood group 2.00（-1.65,6.90）s was significantly longer than that in the fresher blood group 0.00 （-4.30,2.90）s（P<0.05）. Conclusion The results showed that different erythrocyte storage duration has little effect on blood indexes of patients with the open heart surgery by CPB,but it is more important to pay attention to monitor coagulation function changes in the older blood group.

Key words: Erythrocyte storage duration, Children, Cardiopulmonary bypass, Open heart surgery, Blood indexes