Is the precise control of circulating heparin levels during cardiopulmonary bypass beneficial in paediatric open-heart surgery?

Twenty patients, aged 4 months to 17 years, undergoing elective cardiac surgery were prospectively randomized to receive either a standard dose of heparin (300 IU/kg) (Group A, n = 10) or a dose sufficient to achieve a whole blood heparin concentration [Hep]=4.8 IU/ml (Group B, n = 10). ACT was maintained > 480 s in both groups. [Hep] was measured by on-site testing with a heparin-protamine titration method (HMS, Medtronic, Inc.). The following variables were studied: prothrombin fragments (PF1+2), D-dimers (D-d), β-thromboglobulin (β-TG), platelet count, postoperative blood losses, standardized blood and blood products administration, intensive care and hospital stay.The groups were comparable with regards to age, weight, disease complexity, duration of CPB and a number of other variables. The results are summarized in the Table.Blood losses during the first 24 h (26.4 ± 4.7 vs 15.2 ± 3.7 ml/kg/24 h, P = 0.05) and requirement for transfusion of blood (11.4 ± 3.6 vs 3.1 ± 1.3 ml/kg, P = 0.05) and fresh frozen plasma (6.1 ± 2.2 vs 0.9 ± 0.3 ml/kg, P = 0.09) were lower in Group B, when compared to Group A.Management of anticoagulation during CPB aiming to achieve and maintain an [Hep] significantly higher than 'normal' results in less activation of the coagulation cascade, lower fibrinolysis, and lower blood losses and need for tranfusions. Further studies, on a larger number of children, are warranted to better define the clinical impact of these findings.