Alterations Of Hemostasis During Cardiopulmonary Bypass (CPB): A Comparison Between Membrane And Bubble Oxygenators

Abstract

Alterations of hemostasis during cardiopulmonary bypass (CPB) using bubble oxygenators have been previously defined and found to consist of a severe platelet function defect, a primary hyperfibrino(geno)lytic syndrome, and minimal thrombocytopenia. This study compares defects in hemostasis with membrane oxygenators and bubble oxygenators. 30 consecutive patients were studied and all patients studied were undergoing elective coronary artery bypass surgery. Tests of hemostasis included thrombin and reptilase times, protamine corrected thrombin times, soluble fibrin monomer, fibrinogen degradation products, fibrinolytic assays, platelet counts, and tests of platelet function. Studies were drawn pre-bypass, mid-bypass, and 1 hour post bypass. It was found that thrombocytopenia was much less in membrane patients. All patients developed a primary hyperfibrino(geno)lytic syndrome and the degree of this was equal in bubble or membrane oxygenators. Platelet dysfunction also was seen in all patients but was significantly different between the two oxygenation systems. At one hour postop, membrane patients showed no correction of platelet function as assessed by adhesion (14%), while those perfused with bubble oxygenators showed significant correction (67%) at one hour postop.In conclusion, the primary hyperfibrino(geno)lytic syndrome occurring during cardiopulmonary bypass appears to be of equal significance regardless of oxygenation mechanism. Less thrombocytopenia, but more platelet dysfunction is seen with the membrane system.

Hemostasis Defects Associated with Cardiac Surgery, Prosthetic Devices, and Other Extracorporeal Circuits

“…In our experience, the type of oxygenation mechanism used appears to play little role, if any, in causing clinically significant thrombocytopenia. 25 Thrombocytopenia with bubble oxygenators is slightly greater than that seen with membrane oxygenators, but this does not often reach clinical significance. The most commonly cited mechanisms for the development of CPB thrombocytopenia are hemodilution, formation of intravascular platelet thrombi, platelet utilization in the pump and/or oxygenation system, and peripheral utilization due to DIC.…”

The Clinical Significance of Fibrinogen Degradation Products

“…More recent studies, which have utilized more specific methods for assessing fibrinolysis, have confirmed earlier reports of a primary hyperfibrino(geno)lytic syndrome in the majority of patients undergoing cardiopulmonary bypass. 24 Figure 14 depicts changes in the fibrinolytic system in patients undergoing cardiopulmonary bypass.…”

“…In fact, the pathogenesis of fibrinolytic activation during cardiopulmonary bypass remains totally unclear and the degree of fibrinolysis appears to be equal between bubble and and membrane oxygenation systems. 24 Solid tumors have been reported to be associated with a clinical hyperfibrino(geno)lytic syndrome. 89 The spectrum of tumors involved is wide and includes breast, lung, gallbladder, prostatic, and gastrointestinal malignancies, but the most pronounced effect is seen in the sarcomas.…”