Device and a method for determining blood recirculation in a vascular access

摘要

A method is described for determining recirculation of blood in a vascular access of a patient undergoing dialysis treatment using a dialysis machine with an arterial line for withdrawing blood from the patient's body, a dialysis filter, and a venous line for returning blood to the patient's body. The method induces a disturbance in the blood flowing in the venous line. The disturbance is of a magnitude capable of bringing the system into a transient state and determining blood recirculation in the vascular access during the transient state as a function of the magnitude of the disturbance induced in the arterial line. In particular, the disturbance relates to the variation of the hemoglobin concentration in the blood flowing in the venous line. The variation is caused by controlling a change in the ultrafiltration flow in the dialysis filter.