Apparatus for determining a parameter indicative of the progress of an extracorporeal blood treatment

Abstract

An apparatus for extracorporeal treatment of blood (1) comprising a treatment unit, a blood withdrawal line, a blood return line, a preparation line and a spent dialysate line. A control unit (10) is configured to calculate values of a parameter relating to treatment effectiveness based on measures of the conductivity in the spent dialysate line. The value of the effectiveness parameter is calculated using one or more values representative of the conductivity in the spent dialysate line obtained relying on a mathematical model.

Description

technical field [0001] The present invention relates to a device for determining parameters (called effectiveness parameters) indicative of the progress of extracorporeal blood treatment, in particular purification treatments aimed at alleviating renal insufficiency, such as but not limited to blood Dialysis or hemodiafiltration. Also disclosed is a method of determining said parameter indicative of the progress of extracorporeal blood treatment. This parameter can be, for example, one of the following: [0002] - the concentration of a given solute (for example, sodium) in the blood, [0003] - the actual dialysis rate D or the actual clearance K of the exchanger for a given solute (dialysis rate D and clearance K indicate the purification efficiency of the hemodialyzer or hemofilter used in blood treatment), [0004] - the dialysis dose given after the treatment time t, which can be related to the dimensionless ratio Kt / V according to the studies of Sargent and Gotch, whe...

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Problems solved by technology

In other words, throughout the process of changing the conductivity / concentration of the dialysate upstream of the dialyzer or hemofilter and measuring the corresponding change in conductivity / concentration downstream, the control system of the dialysis machine does not allow for implementations that could affect the conductivity or composition of the dialysate. other tasks, thereby limiting the operational flexibility of the dialysis machine

[0021] Furthermore, the method described above is sensitive to artifacts that may be present in the conductivity measured downstream of the dialyzer, which may be caused by several factors (e.g. air bubbles present in the dialysis circuit, activation / deactivation of some actuators such as pumps, etc. , valve open or close, etc.)

[0022] Additionally, it may be difficult to accurately measure the properties of the fluid downstream of the dialyzer due to several factors

In fact, in the case of a step-like upstream perturbation, it may be difficult to measure the asymptotic value of the response unless the downstream conductivity is measured for a relatively long time

On the other hand, it can be difficult to correctly interpret sensor detections without sinusoidal upstream perturbations that do not lead to any equilibrium state

[0023] In addition, hydraulic delays caused by the dialyzer or hemofilter, damping effects, the effect of blood conductivity / concentration on the value of the baseline conductivity downstream of the dialyzer or hemofilter, and noise caused by the machine and its components can make it more difficult to Interpret signals detected by sensors, especially in the presence of continuously varying disturbances

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