Effects of blood washing and autotransfusion during cardiopulmonary bypass on erythrocyte immune and kidney function

Objective To study changes of erythrocyte immune and kidney function after autotransfusing washed red blood cells during cardiopulmonary bypass ( CPB) . Methods Thirty-two patients undergoing valve replacement with CPB were randomly divided into study group and control group (16 in each group). In study group, the blood in operative field and the residual blood in the extracorporal machine were collected, centrifuged, washed and retransfused to patients. Patients in control group were transfused with the residual blood in the extracorporal machine without any disposal or banked blood. All patients were used with membrane oxygenator. Before CPB, 12 h、24 h、72 h and 7 d after CPB, whole blood were taken, then the erythrocyte immune function(C3bRR, RICR) and level of plasma free hemoglobin (FHB) were assayed, and post-operation renal function were compared between the two groups. Moreover, total volume of banked blood transfused to patients after CPB were recorded. Results (1) After 12 hours, 24 hours,72 hours, 7days of CPB, the RBC-C3bRR ( 14. 3%±4. 7%、15. 9%±3. 6%、16. 6%±2. 8%、19. 9%±4. 1 % ) and RBC-ICR(8. 7%±1. 9%、9. 2%±2.0 %、9. 5%±2. 6%、12. 0%±2. 0% ) in study group were significantly elevated than that in control group( RBC-C3bRR 10. 7%±2.4%、11. 3%±3. 0%、12.3%±3. 5%、14.5%±2. 0%、RBC-ICR 5. 9%±1.4%、6.0%±1. 8%、7.0%±1.7%、8.7%±2. 7% ). The erythrocyte immune function after CPB was better and restored faster in study group than that in control group (P 0. 05 in all). (2) After 12 hours,24 hours of CPB,the levels of FHB (0. 41 g/L±0. 13 g/L、0. 03 g/L±0.02 g/L) in study group were significantly lower than that in control group (1.02 g/L±0.23 g/L、0. 54 g/L±0.09 g/L) (P 0.01). After 24hours of CPB, the level of urinary protein excretion (0.19 g/d±0.08 g/d) in study group was significantly lower than that in control group (0. 32 g/d±0.07 g/d) (P 0.05). (3 ) After 24 hours of CPB, the level of 24 h creatinine clearance was significantly elevated in study group (68 ml·min-1·1. 73 m-2±10 ml·min-1·1. 73 m-2) than that in control group (45 ml·min-1·1.73 m-2±4 ml·min-1·1.73 m-2) (P0.01) . (4) The total volume of banked RBCs transfused after CPB were fewer in study group (2. 0 U±1. 1 U) than that in control group (7.4 U±2.3 U) ( P 0. 01) . Conclusion Autotransfusion of washed red blood cells during CPB may improve significantly the erythrocyte immune function and protect kidney function better than transfusion of residual blood in the extracorporal machine or banked blood.