Patent ID: 7172569

Claim:
A device for determining blood flow in a vascular access during an extracorporeal blood treatment, comprising: an arterial branch of an extracorporeal circulation in fluid connection with the vascular access at an arterial connection; a blood treatment unit for receiving blood from the arterial branch; a venous branch of the extracorporeal circulation in fluid connection with the vascular access at a venous connection; a blood pump connected to the extracorporeal circulation; a control unit for varying the flow rate of the blood pump; at least one of an arterial pressure measurement device for measuring pressures p art , p art comp , respectively, in the arterial branch of the extracorporeal circulation with the vascular access open and with the vascular access interrupted when there is no blood flow through the vascular access between the arterial connection and the venous connection, and a venous pressure measurement device for measuring pressures p ven , p ven comp , respectively, in the venous branch of the extracorporeal circulation with the vascular access open and with the vascular access interrupted when there is no blood flow through the vascular access between the arterial connection and the venous connection; a memory unit for storing at least one of the measured arterial and venous pressures; and a computer unit configured to calculate the blood flow Q F in the open vascular access from the measured values of the arterial pressures p art , p art comp or the venous pressures p ven , p ven comp .