Platelet Activity of Residual Blood Remained in the Cardiopulmonary Bypass Circuit After Cardiac Surgery

BACKGROUND: We measured the platelet count and platelet function in residual blood in the cardiopulmonary bypass (CPB) circuit after cpb and compared them with data before CPB operation.

METHODS: The subjects included 34 cases of patients subjected to CPB surgery. The residual blood was concentrated by ultrafiltration after CPB, collected in the bag and the platelet count and platelet activity was measured. ADP 2, 5, 10 microM was used as agonists and measurement was made by turbidimetry.

RESULTS: The mean value of the platelet count was 18.3+/-5.65×10(4)/mm(3) before surgery and 17.2+/-8.39×10(4)/mm(3) in the residual blood, there is no difference. Concerning the platelet aggregation activity, the maximum aggregation rate decreased significantly with ADP 2 microM from 47.4+/-19.6% before surgery to 27.1+/-17.2% in the residual blood (p<0.01). Likewise, it decreased significantly with ADP 5 and 10 microM. The reduction rate of the platelet aggregation activity was higher in the group of not less than 100 minutes compared with the group of less than 100 minutes, but no significant difference was found. CONCLUSION: Autotransfusing whole blood per se without the “cell saver” treatment is more advantageous to keep hemostasis function after surgery since many platelets having the aggregation activity exist in residual blood in the CPB circuit.