De effecten van verschillende doseringsverhoudingen van middelen die de stolling remmen of activeren op bloedverlies tijdens hartchirurgie.

Prior to, and during cardiopulmonary bypass, heparin is transfused in order to avoid massive coagulation activation by the contact surface of the heart-lung-machine. Heparin dosing is commonly based on bodyweight and activated clotting time (ACT). After cardiopulmonary bypass, protamine is transfused to neutralize heparin, thereby reactivating the clotting cascade. Protamine forms a 1:1 salt complex with heparin, but may exhibit an intrinsic anticoagulant activity after overdosing.
According to current guidelines, protamine dosing is performed in a 1.0-1.3:1.0 ratio with heparin. However, our own observations and several literature reports suggest that, due to the degrading and loss of heparin during surgery, protamine is usually overdosed. The consequent overdosing of protamine might deteriorate postoperative hemostasis. The present study investigates whether the use of a lower dosing protamine-to-heparin dosing ratio (0.8) is superior as compared to a high protamine-to-heparin dosing ratio (1.3) with respect to postoperative hemostasis, blood loss and transfusion.

It is hypothesized that a low protamine-to-heparin ratio leads to improved hemostasis after cardiac surgery with cardiopulmonary bypass as compared to a high ratio as measured by rotational thromboelastometry, and reduces postoperative blood loss and blood product transfusion.

At three time points during cardiac surgery (before cardiopulmonary bypass, and at 3 and 30 minutes following protamine administration, blood samples are drawn for further analysis. Postoperative hemostasis monitoring continues until 24 hours following surgery.

Prior to and during cardiopulmonary bypass heparin is transfused in order to avoid massive coagulation activation by the contact surface of the heart-lung-machine. This administration is based on the bodyweight and activated clotting time (ACT) of the patient after heparin administration. Protamine is transfused after cardiopulmonary bypass in order to inactivate the heparin and thereby reactivate clotting. It does so by forming a 1:1 salt complex with heparin. The protamine dosing is according to current guidelines done in a 1.0-1.3 : 1.0 ratio with heparin. However it is suggested that due to the degrading and loss of heparin during surgery using this approach protamine is overdosed when transfused. Since protamine itself has anticoagulant properties this would deteriorate postoperative hemostasis.



Therefore this study investigates if the use off a lower dosing ratio (0.8) is superior as compared to the general protamine dosing, a high protamine-to-heparin dosing ratio (1.3).