Severely ill patients admitted to the intensive care unit may develop an acute failure of kidney function. To bridge the period to recovery, renal function is temporarily replaced by continuous venovenous hemofiltration (CVVH). To prevent clotting of the hemofiltration circuit, heparin is generally used, providing anticoagulation in the circuit and the patient. As a result, bleeding complications may occur, necessitating the transfusion of blood. Anticoagulation of the circuit can also be obtained with the use of tri-sodium citrate, which provides anticoagulation of the circuit without affecting coagulation in the patient and thus without increasing his/her risk of bleeding. The use of citrate may however cause metabolic complications.