Dialysis recirculation monitoring

摘要

A process and device are disclosed for monitoring recirculation during an extracorporeal blood treatment. The blood to be treated flows in an extracorporeal circuit (7) through the blood chamber (10) of a dialyser (8) subdivided by a semipermeable membrane into a blood chamber (10) and a dialysis liquid chamber (9) and the dialysis liquid flows in a dialysis liquid path through the dialysis liquid chamber (9) of the dialyser (8). According to the disclosed process, a short-term concentrate bolus is added to the dialysis liquid flowing through the dialyser (8) or blood flow is distinctly slowed down for a short period. When the blood flowing in the venous branch (24) of the extracorporeal circuit (7) begins to flow in the body, the change of dialysis liquid output concentration (Cdo) also becomes visible for the same time. After the recirculation time has elapsed, part of the sang appears again at the dialyser (8) and causes again a change in the dialysis liquid output concentration (Cdo). The time variation of the change in the dialysis liquid output concentration (Cdo) is sensed and the recirculation is determined from the time variation of the change. The disclosed process is advantageous in that it does not require any measurement sensors in the arterial or venous branch (23, 24) of the extracorporeal circuit (7) to sense measurement values. The whole sensing equipment is limited to the detectors which are in general already provided at the less failure-prone dialysat side of known blood treatment devices.