Normally blood starts to clot as soon as it leaves the body. To prevent clotting of the blood in the filter, the blood has to be 'anticoagulated'. For this purpose, heparins are generally used. Heparins make the blood less likely to clot. Drawback of the use of heparins is that they not only prevent clotting of blood in the circuit and the filter, but also in the patient. Heparins thereby increase the risk of bleeding. Intensive care patients are at higher risk of bleeding due to a recent operation or trauma, ulcers in the mouth or the stomach, or abnormalities in their blood to the acute illness. Due to the continuous application of CVVH for days, anticoagulation is administered without interruption over prolonged periods of time. Studies report bleeding complications in 5 to 50% of the patients. As a result of bleeding, patients need blood transfusion and sometimes surgery. Control of bleeding is sometimes extremely difficult.