METHOD FOR DETERMINING THE REDUCTION RATIO OR THE Kt/V VALUE OF A KIDNEY SUBSTITUTION TREATMENT AND APPARATUS FOR THE REALISATION OF THE METHOD

• US 20100213127A1
• Filed: 06/20/2008
• Published: 08/26/2010
• Est. Priority Date: 06/20/2007
• Status: Active Grant

• Current Assignee: B. Braun Avitum AG (B. Braun Holding GmbH & Co. KG)
• Original Assignee: B. Braun Avitum AG (B. Braun Holding GmbH & Co. KG)
• Inventors: Castellarnau, Alex
• Granted Patent: US 8,702,979 B2
• Time in Patent Office: Days
• US Class Current: 210/647
• CPC Class Codes: A61M 1/16 with membranes
• CPC Class Codes: A61M 1/1609 after use, i.e. downstream of dialyser
• CPC Class Codes: A61M 1/1613 Profiling or modelling of patient or predicted treatment evolution or outcome
• CPC Class Codes: A61M 1/1694 with recirculating dialysing liquid
• CPC Class Codes: A61M 1/3406 Physical characteristics of the filtrate, e.g. urea
• CPC Class Codes: A61M 1/361 before treatment
• CPC Class Codes: A61M 1/3612 after treatment
• CPC Class Codes: A61M 2202/0498 Urea
• CPC Class Codes: A61M 2205/15 Detection of leaks
• CPC Class Codes: A61M 2205/3313 used specific wavelengths
• CPC Class Codes: A61M 2205/3334 Measuring or controlling the flow rate
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 2230/20 Blood composition characteristics

Abstract

A method for determining online adequacy parameters for any hemodialysis, hemofiltration and hemodiafiltration treatment modality is provided. Blood equilibrated dialysate samples at the begin and/or at the end of the treatment; and a continuous measurements of waste compounds in the effluent dialysate by means of spectroscopic techniques, are required. With the data coming from the measurements and a simple mathematic approach Kt/V and reduction ratios for different compounds, which are important from the medical point of view, are obtained.

Claims

1-14. -14. (canceled)

15. A Method for determining the reduction ratio or the Kt/V value of a kidney substitution treatment wherein the measurement of the concentration of at least one waste product is effected spectrophotometrically and directly on the effluent kidney substitution treatment liquid, the method comprising:

recirculating an effluent kidney substitution treatment liquid against the blood flowing through the kidney substitution until the spectrophotometrical value of the effluent kidney substitution treatment liquid has reached a (nearly) constant value A_B0 and

determining the reduction ratio (RR) of the at least one waste product with the equation

$\mathrm{RR}=1<br><br>\frac{A_{B<br><br>\left(t\right)}}{A_{\mathrm{B0}}}.$

or the value Kt/V value with the equation

$\mathrm{Kt}/V=-1<br><br><br><br>n<br><br>\frac{A_{B<br><br>\left(t\right)}}{A_{\mathrm{B0}}}$

wherein A_B(t) is the spectrophotometrical value on the effluent kidney substitution treatment liquid at the treatment time t during the kidney substitution treatment which is commenced after the recirculation of the effluent kidney substitution treatment liquid and wherein K is the effective clearance of the waste product and V is the distribution volume of the waste product.

16. Method according to claim 15, characterised in that the kidney substitution treatment is commenced on cessation of the recirculation of the effluent kidney substitution treatment liquid.

17. Method according to claim 15, characterised in that the effluent kidney substitution treatment liquid is recirculated against the blood flowing through the kidney substitution after a predetermined treatment time or after the RR or the Kt/V, respectively, has reached a predetermined value.

18. Method according to claim 15, characterized in that the absorbance or the transmission of electromagnetic radiation is measured to determine the spectrophotometrical values of the effluent kidney substitution treatment liquid.

19. Method according to claim 18, characterized in that ultraviolet light is used as electromagnetic radiation.

20. Method according to claim 19, characterized in that the wavelength of the ultraviolet light is in the range 180 nm to 380 nm.

21. Method according to claim 20, characterized in that the wavelength of the ultraviolet light is in the range 200 nm to 320 nm.

22. Method according to any of the claims 15, characterized in that as waste product at least one of urea, uric acid, creatinine, phosphates, B2 microglobuline, B12 vitamin (or any other compound which has to be cleared from the blood of the patient) is used.

23. Method according to claim 15, characterized in that hemodialysis, hemofiltration, pre-dilution hemofiltration, post-dilution hemofiltration, pre-post-dilution hemofiltration, hemodiafiltration, pre-dilution hemodiafiltration, post-dilution hemodiafiltration or pre-post-dilution hemodiafiltration is used as kidney substitution treatment.

24. Method according to claim 15, characterized in that the determination of A_B(t) is performed continuously.

25. An apparatus for determining the reduction ratio or the Kt/V value of a kidney substitution treatment comprising:

a kidney substitution device;

an external blood circuit which is connected to the kidney substitution device;

a kidney substitution liquid conduit system which is connected to the kidney substitution device, a kidney substitution liquid source and a kidney substitution liquid drain wherein the kidney substitution liquid conduit system comprises a valve system to recirculate the effluent kidney substitution treatment liquid of the kidney substitution device to the kidney substitution device;

wherein a measuring device for determining spectrophotomertric values of the effluent kidney substitution treatment liquid is located at the outflow of the kidney substitution treatment liquid conduit between the kidney substitution device and the kidney substitution liquid drain such that the effluent kidney substitution liquid either has to pass the measuring device during recirculation or has to pass the measuring device as it flows into the kidney substitution liquid drain.

26. Apparatus according to claim 25, characterized in that the measuring device is a spectrophotometer.

27. Apparatus according to claim 25, characterized in that the measuring device is an UV spectrophotometer.

28. Apparatus according to claim 25, characterized in that the valve system comprises:

a valve between the kidney substitution liquid source kidney substitution device,

a valve between the kidney substitution liquid drain and the kidney substitution device,

and two valve in a kidney substitution liquid circuit.