Background

The contact of the blood with non-biological surfaces causes the activation of the coagulation cascade and that is why any extracorporeal treatment of
the blood requires anticoagulant therapy. The systems designed to keep anticoagulated the blood in extracorporeal circuits involve the use of anticoagulants which, such as heparin, act systemically over all the patient’s blood or which, like citrate, are infused directly at the beginning of the circuit anticoagulating only the extracorporeal blood. The use of heparin, having a systemic effect, increases the risk of bleeding complications; the use of citrate, having a local effect in the extracorporeal circuit, prevents this complication but, having a limited clearance, allows anticoagulation blood flows not exceeding 200 mL /min, threshold that can be crossed only causing high systemic toxicity.