Device and method for determining a dialysis fluid flow rate for extracorporeal blood treatment

• US 8,512,271 B2
• Filed: 09/25/2007
• Issued: 08/20/2013
• Est. Priority Date: 09/26/2006
• Status: Active Grant

• Current Assignee: Fresenius Medical Care Deutschland GmbH (Fresenius Medical Care AG)
• Original Assignee: Fresenius Medical Care Deutschland GmbH (Fresenius Medical Care AG)
• Inventors: Moissl, Ulrich, Wpper, Andreas
• Primary Examiner(s): Wiest, Philip R
• Application Number:
  US12/443,001
• Publication Number:
  US 20100042035A1
• Time in Patent Office: 2,156 Days
• Field of Search: 604 401- 614, 604 19- 22, 604 29- 31, 210/321.7, 210645-647, 422 44- 48, 128/898
• US Class Current: 604/6.11
• CPC Class Codes: A61M 1/16 with membranes
• CPC Class Codes: A61M 1/1613 Profiling or modelling of patient or predicted treatment evolution or outcome
• CPC Class Codes: A61M 1/1615 using measurements made at different flow rates
• CPC Class Codes: A61M 1/3607 Regulation parameters
• CPC Class Codes: A61M 2205/3331 Pressure; Flow
• CPC Class Codes: A61M 2205/3334 Measuring or controlling the flow rate
• CPC Class Codes: A61M 2205/50 with microprocessors or computers

Abstract

The present invention relates to a device and to a method for determining the dialysis fluid flow rate for an extracorporeal blood treatment device. The dialysis fluid flow rate Q_d is determined in accordance with the blood flow rate Q_b or the blood flow rate Q_b is determined in accordance with the dialysis fluid flow rate Q_d, wherein by increasing about a specific value, the increase of a variable characterising the efficiency of the blood treatment, in particular clearance K, does not exceed the specific value. The present invention also relates to a blood treatment device comprising a device for determining the dialysis fluid flow rate or blood flow rate and to a method for operating an extracorporeal blood treatment device. As a result, an optimal dialysis fluid flow rate and/or blood flow rate calculates the requirement in accordance with a high efficiency of the dialysis treatment and in accordance with a reduced consumption of the dialysis liquid.

Claims

1. A system for pre-setting a flow rate for an extracorporeal blood-treating apparatus comprising a dialyser divided into a blood chamber and a dialysis chamber by a semi-permeable membrane, wherein blood flows through the blood chamber and dialysis fluid flows through the dialysis chamber, said system comprising

a means for selecting an optimum flow rate, said means for selecting an optimum flow rate being selected from the group consisting of:

a means for selecting an optimum dialysis fluid flow rate Q_dopt as a function of a pre-set blood flow rate Q_b, wherein Q_dopt for the pre-set blood flow rate Q_b is a solution for Q_dopt such that if Q_dopt were increased by a first given amount, a metric characteristic of the effectiveness of the blood treatment would increase by approximately a second given amount; and

a means for selecting an optimum blood flow rate Q_dopt as a function of a pre-set dialysis fluid flow rate Q_d, wherein Q_bopt for the pre-set dialysis fluid flow rate Q_d is a solution for Q_bopt such that if Q_bopt were increased by a third given amount, a metric characteristic of the effectiveness of the blood treatment would increase by approximately a fourth given amount,

wherein the means for selecting Q_dopt or the means for selecting Q_bopt is a calculating unit configured such that Q_dopt or Q_bopt is calculated from a mathematical equation by an iterative approximate solution method.

2. The system of claim 1, wherein the metric characteristic of the effectiveness is a clearance K of the dialysis treatment.

3. The system of claim 2, configured such that Q_bopt or Q_dopt is selected as a function of a metric characteristic of the dialyser.

4. The system of claim 1, configured such that Q_bopt or Q_dopt is selected as a function of a metric characteristic of the dialyser.

5. The system of claim 4, wherein the metric characteristic of the dialyser is a mass transfer coefficient k0A of the dialyser.

6. The system of claim 5, further comprising

an input unit for presetting various modes of treatment in which the effectiveness of the blood treatment differs, configured such that for a first given mode of treatment and a second given mode of treatment:

a ratio of the first given amount to the second given amount for the first given mode of treatment differs from a ratio of the first given amount to the second given amount for a second given mode of treatment;

or

a ratio of the third given amount to the fourth given amount for the first given mode of treatment differs from a ratio of the third given amount to the fourth given amount for the second given mode of treatment.

7. The system of claim 1, further comprising:

an input unit for presetting various modes of treatment in which the effectiveness of the blood treatment differs, configured such that for a first given mode of treatment and a second given mode of treatment;

a ratio of the first given amount to the second given amount for the first given mode of treatment differs from a ratio of the first given amount to the second given amount for the second given mode of treatment;

or

a ratio of the third given amount to the fourth given amount for the first given mode of treatment differs from a ratio of the third given amount to the fourth given amount for the second given mode of treatment.

8. The system of claim 1, wherein the mathematical equation is a multi-order polynomial.

9. A blood-treating apparatus for the extracorporeal treatment of blood, comprising:

a dialyser divided by a semi-permeable membrane into a blood chamber and a dialysis chamber, wherein blood flows through the blood chamber at a pre-set blood flow rate Q_b, or a dialysis fluid flows through the dialysis chamber a pre-set dialysis fluid rate Q_d; and

the system for pre-setting a flow rate of claim 1.

10. The blood-treating apparatus of claim 9, further comprising:

a control unit for pre-setting Q_d or Q_b.

11. The blood-treating apparatus of claim 10, further comprising:

at least one of;

a dialysis-fluid pump for pumping the dialysis fluid, and

a blood pump for pumping blood,

wherein the control unit is configured to set the speed of the dialysis fluid pump at the pre-set dialysis flow rate Q_d or to set the speed of the blood pump at the pre-set blood flow rate Q_b.

12. A method for pre-setting a dialysis fluid flow rate or a blood flow rate for an extracorporeal blood-treating apparatus comprising a dialyser divided into a blood chamber and a dialysis chamber by a semi-permeable membrane, wherein the blood flows through the blood chamber and dialysis fluid flows through the dialysis chamber, the method comprising:

selecting an optimum dialysis fluid flow rate Q_dopt as a function of a pre-set blood flow rate Q_b at a pre-set blood flow rate Q_b such that if Q_dopt were increased by a first given amount, a metric characteristic of the effectiveness of the blood treatment would increase by approximately a second given amount;

or

selecting an optimum blood flow rate Q_bopt as a function of a pre-set dialysis fluid flow rate Q_d at a pre-set dialysis fluid flow rate Q_d such that if Q_bopt were increased by a third given amount, a metric characteristic of the effectiveness of the blood treatment would increase by approximately a fourth given amount,

wherein Q_dopt or Q_bopt is calculated from a mathematical equation by an iterative approximate solution method.

13. The method of claim 12, wherein the metric characteristic of the effectiveness is a clearance K of the dialysis treatment.

14. The method of claim 12, further comprising selecting Q_bopt or Q_dopt as a function of a metric characteristic of the dialyser.

15. The method of claim 14, wherein the metric characteristic of the dialyser is a mass transfer coefficient k0A of the dialyser.

16. The method of claim 12, further comprising:

presetting at least two modes of treatment in which the effectiveness of the blood treatment differs, such that for a first given mode of treatment and a second given mode of treatment;

a ratio of the first given amount to the second given amount for the first given mode of treatment differs from a ratio of the first given amount to the second given amount for the second given mode of treatment;

or

a ratio of the third given amount to the fourth given amount for the first given mode of treatment differs from a ratio of the third given amount to the fourth given amount for the second given mode of treatment.

17. The method of claim 12, wherein the mathematical equation is a multi-order polynomial.

18. A method comprising:

performing the method for pre-setting the dialysis fluid flow rate or the blood flow rate of claim 12; and

operating the extracorporeal blood-treating apparatus comprising a dialyser divided by a semi-permeable membrane into a blood chamber and a dialysis chamber, wherein blood flows through the blood chamber at the pre-set blood flow rate Q_b, or a dialysis fluid flows through the dialysis chamber at the pre-set dialysis fluid rate Q_d.