Transfusion of patients undergoing cardiopulmonary bypass

Hemotherapy in open heart surgery

The clinical charts and transfusion records of 216 patients who underwent open heart surgery with cardiopulmonary bypass between August 1983 and July 1684 were reviewed. The patients were categorized into five groups according to their operative procedures. Findings from preoperative hemostatic function tests in all groups were normal. Heparin rebound was observed in all groups, probably due to underneutralization by protamine. The results suggest that the neutralization dose of protamine per milligram of heparin should be increased to a range of between 1.5 and 1.7 mg in the post-cardiopulmonary bypass period. This should also reduce the need for fresh frozen plasma. Non-blood priming of the pump for adults and acceptance of a degree of thrombocytopenia (in the range of 60 to 80 x 10(9)/L) after cardio-pulmonary bypass will lower the blood component usage. A preoperative blood order schedule for patients with open heart surgery/cardiopulmonary bypass has been suggested.

Heparin monitoring and neutralization during cardiopulmonary bypass using a rapid plasma separator and a fluorometric assay

Avoidance of over- or underheparinization during cardiopulmonary bypass (CPB) is crucial in preventing bleeding or clotting. Currently no completely satisfactory method is available for measuring heparin levels--a method that would be rapid, inexpensive, specific, and reproducible. We combined the use of two devices, a rapid plasma separator and a fluorometric heparin assay system, in an attempt to satisfy these requirements in 15 patients having CPB during cardiac surgical procedures. The first instrument separates plasma from whole blood using a pneumatic filtration principle, while the heparin assay system measures the effect of heparin on thrombin conversion of a synthetic fluorogenic substrate. Accurate plasma heparin levels can be generated in less than five minutes, and the assays are inexpensive and easy to perform. Performing heparin assays at critical intervals during CPB allowed desired heparin levels to be maintained and the protamine dose for heparin neutralization to be reduced to a minimum. In addition, studies for heparin rebound revealed negligible rebound up to six hours postoperatively despite the reduced doses of protamine. There were no hemorrhagic or clotting complications in the series.