APPARATUS AND METHOD FOR CONTROLLING INFUSION RATE OF PRE- AND POST-DILUTION IN EXTRACORPOREAL BLOOD TREATMENT

An apparatus (1a) for extracorporeal blood treatment, comprising an infusion control arrangement (8) arranged for infusing a pre-dilution flow rate upstream a blood treatment unit (4) and a post-dilution flow rate downstream the blood treatment unit (4), an ultrafiltration, UF, arrangement (40) arranged for ultrafiltration of a liquid through a semipermeable membrane (7) of the blood treatment unit (4) and a control unit (31). The control unit (31) is configured to configure the infusion control arrangement (8) to obtain a plurality of different configurations of the pre-dilution flow rate and/or post-dilution flow rate. For each of the plurality of different configurations, the control unit (31) is configured to change an operating situation of the UF arrangement (40), to detect a plurality of ultrafiltration flow rate values through the membrane (7) as a function of TMP, on changing said operating situation, and to evaluate an optimal ultrafiltration flow rate value from a comparison of the detected ultrafiltration flow rates. The apparatus (1a) is also configured to estimate a clearance value for a certain solute at the optimal ultrafiltration flow rate value and to evaluate a preferred configuration of the pre-dilution flow rate and/or post-dilution flow rate from a comparison of the corresponding estimated clearance values.