The Effects Of Platelepheresis On The Blood Conservation During Cardiac Surgery With Cardiopulmonary Bypass

Objectives: This study was undertaken to investigate the inference of cardiopulmonary bypass on the blood system, especially in platelet quantity and function, and to evaluate the effects of plateletpheresis in the blood conservation following cardiopulmonaiy bypass. We also discuss its mechanism further more. Methods: 21 patients undergoing open-heart surgery were divided randomly into control or experimental groups. There was no significant difference between two groups with respect to preoperative perameters, CPB time and postoperative hematocrit. All patients underwent routine CPB. Plateletpheresis was used to sequestrate platelet concentrates (PCs) in the experimental group by COBE SPECTRA, but other blood conservation approaches were similar between the two groups. Blood samples were taken to measure haemoglobin, haematocrit, platelet count, fibrinogen, prothrombin time(PT), platelet x -granule membrane glycoprotein 1 40(GMP- 140), 13 -thromboglobulin( 13 -TG), D-dimer at seven time points perioperatively. In order to mitigate the effect of hemodilution, the platelet count and plasma level of soluble GMP-140, 13 -TG, D- dimer in each sample were standardized to the pre-operation level using the haemotocrit(I-ICT) value with Taylor's formula ( Corrected value of components = measured value x HCT before operation/HCT when sample was taken). The chest tube drainage during 2 hours, 4 hours, 8 hours, 16 hours, 24 hours and total drainage volume after operation were recorded respectively, the amount of blood transfusion during and after operation and mechanical ventilated support time after operation were also observed. The results were expressed as the mean and the standard deviation of mean (x ?SD). Statistical analysis of all values was performed using SPSS 8.0. LSD was used to assess differences inter-group and Independent-sample T test was employed to assess those between groups. Results: 1) The chest tube drainage during 2 hours, 4 hours, 8 hours, 16 hours and total drainage after operation was significantly lower in the experiment group than those in the control group. 2) In the control group, the platelet count after operation returned to normal range after 4 hours, but in the first postoperative day it was still lower compared to preoperative level. However, in the experiment group, platelet count was returned to pre-operative level in the first postoperative day. 3) Platelet aggregation restored to pre-operative level in the experimental group whereas of the control group. 4) The plasma level of GMP- 140 and D-dimer during and after CPB was higher than pre-operation in both groups, and there was no significant difference between two groups. 5) The plasma level of 13 -TG was significantly higher after heparin administered as well as during CPB in the experimental group, and returned to baseline after CPB. 6 ) The mechanical ventilated support time was significantly shorter in the experimental group than in the control group. Conclusions: The results demonstrate that 1) CPB have serious effects on blood system. 2) Platelet dysfunction is the main cause of disturbances of the hemostatic system after CPB. 3) Plateletpheresis is beneficial to the recovety of hemostatic system by protect platelets. It is a useful blood conservation method. 4) Plateletpheresis can also reduce the lung injury during CPB 4and postoperative mechanical ventilated support time.