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 of a patient, said apparatus comprising: an extracorporeal blood circuit including a dialyzer, a dialyzate circuit, a control unit, and an online clearance monitor configured to take clearance measurements in real time and to send measurement values of clearance to the control unit, wherein the dialyzer comprises a first chamber, a second chamber, and a semipermeable membrane, the extracorporeal blood circuit is in fluid communication with the first chamber of the dialyzer, the dialyzate circuit includes the second chamber of the dialyzer and further comprises a dialyzate pump that is in fluid communication with the second chamber of the dialyzer, and a dialyzate supply system comprising either (i) different dialysis solutions of different concentrations, stored in different bags, or (ii) a reservoir of dialysis solution and means to vary respective concentrations of one or more ingredients of the dialysis solution, the first chamber and the second chamber are separated from one another by the semipermeable membrane, the dialyzate pump is configured to convey a dialysis solution through the dialyzate circuit; the control unit is configured to operate the apparatus in a first phase of hemodialysis and in a second phase of hemodialysis, the control unit is configured to set a duration of the first phase of hemodialysis based on one or more patient parameters including a concentration of at least one component, the at least one component being present at a concentration in the patient's blood, the control unit is configured to operate the dialyzate pump at a first flow rate during the first phase of hemodialysis, the control unit is configured to operate the apparatus in the second phase of hemodialysis following the first phase of hemodialysis, the control unit is configured to operate the dialyzate pump at a second flow rate during the second phase of hemodialysis, the control unit is configured to set a concentration of the at least one component, in the dialysis solution in the first phase, to be of a relatively higher first concentration, and the control unit is configured to control the dialyzate supply system to provide a concentration of the at least one component, in the dialysis solution in the second phase, to be of a second concentration that is relatively lower than the first concentration and that is set in dependence on the measurement values of clearance sent to the control unit from the online clearance monitor.

2. The apparatus in accordance with claim 1, wherein the control unit is configured to vary each of the first flow rate and the first concentration in the first phase and/or to vary each of the second flow rate and the second concentration in the second phase.

3. The apparatus in accordance with claim 2, wherein the control unit is configured to vary the first flow rate and the first concentration.

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

5. The apparatus in accordance with claim 1, wherein the control unit is configured such that the first phase extends over a time span of from 15 minutes to 60 minutes.

6. The apparatus in accordance with claim 1, wherein the control unit is further configured to operate the apparatus in a conditioning phase in which no dialysis takes place but hemofiltration takes place, before the first phase.

7. The apparatus in accordance with claim 1, wherein the control unit is configured such that the second concentration is set in the second phase in dependence on dialysis dosage (K t/V) reached during the treatment, where t is the treatment time, K is the clearance, and V is the distribution volume of the patient.

8. The apparatus in accordance with claim 1, wherein the control unit is configured such that the transition from the first phase into the second phase takes place continuously or step-wise with respect to setting the second concentration and/or with respect to setting the second flow rate.

9. The apparatus in accordance with claim 1, wherein the control unit is configured to operate the apparatus as a hemodialysis machine or as a hemodiafiltration machine, and optionally as a hemofiltration machine.

10. The apparatus in accordance with claim 1, wherein the control unit is configured such that the first phase extends over a time span of from 20 minutes to 40 minutes.

11. The apparatus in accordance with claim 1, wherein the control unit is configured such that the first phase extends over a time period of 30 minutes.

12. The apparatus in accordance with claim 1, wherein the control unit is configured such that each of the first flow rate and the first concentration is constant in the first phase.

13. The apparatus in accordance with claim 1, wherein the control unit is configured to maintain each of the first flow rate and the first concentration to be constant in the first phase and/or to maintain each of the second flow rate and the second concentration to be constant in the second phase.

14. The apparatus in accordance with claim 2, wherein the control unit is configured to vary the first flow rate and the first concentration in the first phase.

15. The apparatus in accordance with claim 2, wherein the control unit is configured to vary the second flow rate and the second concentration in the second phase.

16. The apparatus in accordance with claim 1, wherein the control unit is configured such that each of the first flow rate and the first concentration is varied in the first phase and the variation takes place linearly, exponentially, or step-wise.

17. The apparatus in accordance with claim 1, wherein the control unit is configured such that each of the second flow rate and the second concentration is constant in the second phase.

18. The apparatus in accordance with claim 1, wherein the control unit is configured such that each of the second flow rate and the second concentration is varied in the second phase and the variation takes place linearly, exponentially, or step-wise.

Description

(1) Further details and advantages of the invention result from an embodiment shown in the drawing.

(2) The only FIGURE shows the progression of the flow rate of the dialysis solution over time in an apparatus in accordance with the invention.

(3) The flow rate of the dialysis solution flowing through the dialyzer is shown on the ordinate and the time on the abscissa.

(4) 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.

(5) 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.

(6) 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.

(7) 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.

(8) 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.

(9) 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.

(10) The reaching of the flow rate in the second phase can take place step-wise or continuously as can be seen from the FIGURE.

(11) 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.