APPARATUS FOR AN EXTRACORPOREAL BLOOD TREATMENT

Abstract

The present invention relates to an apparatus for an extracorporeal blood treatment having an extracorporeal blood circuit in which a dialyzer is arranged and having a dialyzate circuit, wherein the blood circuit is in fluid communication with a first chamber and the dialyzate circuit is in fluid communication with a second chamber of the dialyzer, and wherein the two chambers are separated from one another by a semipermeable membrane, with a dialyzate pump for a conveying of the dialysis solution being present in the dialyzate circuit, wherein the apparatus has a control unit that is configured to operate the apparatus in a first phase and in a second phase following the first phase, wherein the dialyzate pump is operated with a smaller flow rate in the first phase than in the second phase and/or wherein the dialyzate pump conveys a dialysis solution in the first phase that is of a higher concentration with respect to at least one component than in the second phase.

Claims

1. An apparatus for an extracorporeal blood treatment having an extracorporeal blood circuit in which a dialyzer is arranged and having a dialyzate circuit, wherein the blood circuit is in fluid communication with a first chamber and the dialyzate circuit is in fluid communication with a second chamber of the dialyzer, and wherein the two chambers are separated from one another by a semipermeable membrane, with a dialyzate pump for a conveying of the dialysis solution being present in the dialyzate circuit, characterized in that the apparatus has a control unit that is configured to operate the apparatus in a first phase and in a second phase following the first phase, wherein the dialyzate pump is operated with a smaller flow rate in the first phase than in the second phase and/or wherein the dialyzate pump conveys a dialysis solution in the first phase that is of a higher concentration with respect to at least one component than in the second phase.

2. An apparatus in accordance with claim 1, characterized in that the control unit is configured such that the flow rate and/or the concentration is constant or varies in the first phase and/or in the second phase, with the variation preferably taking place linearly, exponentially, or step-wise.

3. An apparatus in accordance with claim 2, characterized in that the control unit is designed such that the variation of the flow rate and/or of the concentration only takes place in the first phase or both in the first and second phases.

4. An apparatus in accordance with claim 1, characterized in that the control unit is configured such that no variation of the flow rate and/or no variation of the concentration takes place in the second phase.

5. An apparatus in accordance with claim 1, characterized in that the control unit is configured such that the first phase extends over a time span of 15 min. to 60 min., preferably over a time span of 20 min. to 40 min., and particularly preferably over a time period of 30 min.

6. An apparatus in accordance with claim 1, characterized in that the control unit is configured such that a conditioning phase in which no dialysis takes place, but rather only hemofiltration, takes place before the first phase.

7. An apparatus in accordance with claim 1, characterized in that the control unit is configured such that the duration of the first phase is dependent on one or more treatment parameters and/or patient parameters.

8. An apparatus in accordance with claim 7, characterized in that the patient parameters are the body weight and/or the distribution volume of the patient and/or the substance concentration in the blood such as the predialytic urea concentration.

9. An apparatus in accordance with claim 1, characterized in that the control unit is designed such that the flow rate and/or the concentration is/are set in the second phase in dependence on the clearance determined during the treatment or on the dialysis dosage reached during the treatment.

10. An apparatus in accordance with claim 1, characterized in that the control unit is designed such that the transition from the first phase into the second phase takes place continuously or step-wise with respect to the concentration and/or with respect to the dialyzate flow.

11. An apparatus in accordance with claim 1, characterized in that the control unit is configured to operate the apparatus as a hemodialysis machine or as a hemodiafiltration machine and optionally at times as a hemofiltration machine.

Description

[0028] Further details and advantages of the invention result from an embodiment shown in the drawing.

[0029] The only Figure shows the progression of the flow rate of the dialysis solution over time in an apparatus in accordance with the invention.

[0030] The flow rate of the dialysis solution flowing through the dialyzer is shown on the ordinate and the time on the abscissa.

[0031] As can be seen from the Figure, an increase of the flow rate of the dialysis solution through the dialyzer takes place in a first phase P1 after a conditioning phase (point A) in which no diffuse mass transfer, but only a convective mass transfer of blood via the membrane into the dialysis solution takes place, with the increase becoming smaller in the first phase as time passes.

[0032] The vertical line in the Figure marks the border between the first and second phases. In the second phase P2, the flow rate of the dialysis solution is higher than in the first phase and largely constant.

[0033] The transition of the progression of the flow rate from the first phase to the second takes place, as can be seen from the Figure, steadily and without steps.

[0034] In the first phase P1, the progression of the flow rate is profiled, with the profile being able to be fixedly predefined or being able to depend on one or more parameters such as on the condition of the patient, on the body weight of the patient, on his distribution volume, etc.

[0035] In the second phase P2, the setting of the flow rate of the dialysis solution takes place in dependence on the clearance K (OCM controlled clearance modeling) measured in the second phase and/or in dependence on the prescribed treatment time in which a specific dialysis dosage has to be reached or in accordance with a prescribed desired value or desired value profile.

[0036] As can be seen from the Figure, a fast removal of salts, urea, etc. is directly prevented at the start of the treatment due to the arising disequilibrium with its consequences associated therewith in that a comparatively small dialysis flow is set. The actually prescribed flow rate of the dialysis solution is therefore not reached by a ramping of the dialysate pump as fast as possible, but is rather reached with a deliberate time delay by a slow increase of the flow rate.

[0037] The reaching of the flow rate in the second phase can take place step-wise or continuously as can be seen from the Figure.

[0038] A slower withdrawal of substances usually excreted in the urine at the start of the treatment with respect to the later treatment can also be achieved in that a different dialysis solution is used at the start of the treatment than at a later time in the treatment. An initially low and then higher reduction of the concentration of the substances in question in the blood can also be achieved in this manner. It is conceivable with this procedure that different dialysis solutions are used that are stored in different bags, etc. or that the concentration of one or more ingredients is varied linearly or step-wise in one and the same reservoir of the dialysis solution.