Method and apparatus for determining a patient's filtration rate

Patent metadata

Field	Value
Publication number	US-11079397-B2
Application number	US-201615558224-A
Country	US
Kind code	B2
Filing date	Mar 24, 2016
Priority date	Mar 24, 2015
Publication date	Aug 3, 2021
Grant date	Aug 3, 2021

Abstract

A method and an apparatus for determining or approximating a patient's glomerular filtration rate or a patient's creatinine clearance are disclosed. The method comprises the following steps: determining a serum creatinine concentration of the patient, determining a lean tissue mass of the patient, and determining the glomerular filtration rate of the patient or the creatinine clearance of the patient based on the serum creatinine concentration of the patient and the lean tissue mass of the patient.

First claim

The invention claimed is:

1. Method for determining or approximating a patient's glomerular filtration rate or a patient's creatinine clearance in a patient undergoing intermittently a renal replacement treatment, the method comprising the steps of:
determining a serum creatinine concentration of the patient,
determining a lean tissue mass of the patient,
determining the glomerular filtration rate of the patient or the creatinine clearance of the patient without using age or gender of the patient and based on the serum creatinine concentration of the patient and the lean tissue mass of the patient,
determining which of chronic kidney disease (CKD) stages 1-5 the patient is in based on the determined glomerular filtration rate or creatinine clearance, and
determining a criterion for applying a renal replacement therapy to the patient based on the determined glomerular filtration rate or creatinine clearance of the patient,

wherein the step of determining the serum creatinine concentration includes determining a first serum creatinine concentration at a first time between treatment sessions and determining a second serum creatinine concentration at a second time between treatment sessions and wherein the step of determining the patient's glomerular filtration rate or creatinine clearance is based on the first creatinine concentration and on the second creatinine concentration.

2. Method according to claim 1 , wherein the step of determining the lean tissue mass includes measuring the lean tissue mass.

3. Method according to claim 2 , wherein the step of measuring the lean tissue mass includes applying a bioimpedance measurement.

4. Method according to claim 1 , wherein the step of determining the serum creatinine concentration includes measuring the serum creatinine concentration from a blood sample of the patient.

5. Method according to claim 1 , wherein the glomerular filtration rate Q gfr is determined by applying the formula:

Q
gfr

=

α
ltm

·

M

LT
m

β
ts

·

[
Cr
]

s

,

wherein M LTm is the lean tissue mass of the patient, [Cr] s is the serum creatinine concentration and α ltm and β ts are proportionality constants.

6. Method according to claim 1 , further comprising the step of measuring the weight gain of the patient between the first time and the second time and wherein the step of determining the patient's glomerular filtration rate or creatinine clearance is based on the weight gain of the patient.

7. Method according to claim 1 , further comprising the step of measuring a total body water of the patient by applying a bioimpedance measurement and wherein the step of determining the patient's glomerular filtration rate or creatinine clearance is based on the total body water of the patient.

8. Method according to claim 1 , wherein the patient's glomerular filtration rate or creatinine clearance is determined at a plurality of times and wherein a timely average is determined of the patient's glomerular filtration rate or creatinine clearance and wherein an outlier is disregarded from the determination of the timely average.

9. Method according to claim 1 , further comprising the step of determining a criterion for the prescription of a diuretic based on the determined glomerular filtration rate or creatinine clearance of the patient.

10. Apparatus for determining or approximating a patient's glomerular filtration rate or a patient's creatinine clearance, the apparatus comprising:
a first receiver configured to receive a serum creatinine concentration of the patient, a second receiver configured to include or connect to a measuring unit for measuring a lean tissue mass of the patient, and a central processing unit configured to determine (i) the glomerular filtration rate Q gfr of the patient by applying the formula

Q
gfr

=

α
ltm

·

M

LT
m

β
ts

·

[
Cr
]

s

wherein M LTm is the lean tissue mass of the patient, [Cr] s is the serum creatinine concentration, and α ltm and β ts are proportionality constants, or (ii) the creatinine clearance of the patient by applying the formula

K
Cr_WB

=

α
ltm

·

M
LT_m

[
Cr
]

s

wherein M LT_m is the lean tissue mass of the patient, [Cr] s is the serum creatinine concentration and α ltm is a proportionality constant, without using age or gender of the patient.

11. Apparatus according to claim 10 , wherein the measuring unit for measuring the lean tissue mass comprises a bioimpedance measuring unit.

12. Apparatus according to claim 10 , wherein the central processing unit is configured to determine a criterion for the prescription of a diuretic based on the determined glomerular filtration rate or creatinine clearance of the patient.

13. Apparatus according to claim 10 , wherein the central processing unit is configured to determine a criterion for applying a renal replacement therapy to the patient based on the determined glomerular filtration rate or creatinine clearance of the patient.

14. Apparatus according to claim 10 , adapted for a patient undergoing a renal replacement therapy, wherein the first receiver is configured to receive a first serum creatinine concentration at a first time between treatment sessions and to receive a second serum creatinine concentration at a second time between treatment sessions and wherein the central processing unit is configured to determine the p

Assignees

• Fresenius Medical Care Deutschland Gmbh

Inventors

• Chamney Paul
• Wabel Peter

Classifications

• G01N2800/347

  Renal failures; Glomerular diseases; Tubulointerstitial diseases, e.g. nephritic syndrome, glomerulonephritis; Renovascular diseases, e.g. renal artery occlusion, nephropathy · CPC title

• G01N33/70 Primary

  involving creatine or creatinine · CPC title

• G01N2800/52

  Predicting or monitoring the response to treatment, e.g. for selection of therapy based on assay results in personalised medicine; Prognosis · CPC title

• A61B5/0531

  Measuring skin impedance · CPC title

• A61P7/10

  Antioedematous agents; Diuretics · CPC title