Method and a Device for Determining the Hydration and/or Nutrition Status of a Patient

• US 20080086058A1
• Filed: 06/29/2004
• Published: 04/10/2008
• Est. Priority Date: 06/29/2004
• Status: Active Grant

• Current Assignee: Fresenius Medical Care Deutschland GmbH (Fresenius SE & Co. KGaA)
• Original Assignee: Fresenius Medical Care Deutschland GmbH (Fresenius SE & Co. KGaA)
• Inventors: Chamney, Paul, Wabel, Peter
• Granted Patent: US 7,917,202 B2
• Time in Patent Office: Days
• US Class Current: 600/547
• CPC Class Codes: A61B 5/0537 Measuring body composition by impedance, e.g. tissue hydration or fat content
• CPC Class Codes: A61B 5/1073 Measuring volume, e.g. of limbs
• CPC Class Codes: A61B 5/4869 Determining body composition
• CPC Class Codes: A61B 5/4872 Body fat
• CPC Class Codes: A61B 5/7278 Artificial waveform generation or derivation, e.g. synthesising signals from measured signals A61B5/327 takes precedence

Abstract

Monitoring the hydration and/or nutrition status of a patient by bioimpedance. A bioimpedance method and device that makes use of a refined model by which the conductivity contributions from intracellular tissues can be taken better into account to enable an improved assessment of the body composition of a patient with increased accuracy. The intracellular volume (ICV) of a patient is determined by determining an intracellular electrical resistance R_mix of the patient and deriving the intracellular volume ICV using R_mix by taking into account that a cell of a kind of tissue contributes differently to the electrical resistance R_mix of the intracellular volume ICV compared with a cell of a second kind of tissue. The application also relates to a device for carrying out the method according to the invention and to a computer program product to be used on such a device.

Claims

1. A method for determining an intracellular volume ICV of a patient comprising the steps of:

determining an intracellular electrical resistance R_mix of the patient,

deriving the intracellular volume ICV using R_mix by taking into account that a cell of a first kind of tissue contributes differently to the electrical resistance R_mix of the intracellular volume ICV compared with a cell of a second kind of tissue.

2. The method according to claim 1 characterised in that it further comprises the steps of determining at least one anthropometric measure X of the patient and to derive the intracellular volume ICV by also using the anthropometric measure X.

3. The method according to claim 2 characterised in that the at least one anthropometric measure X is the height Hgt of the patient.

4. The method according to claim 1 characterised in that it further comprises the steps of determining an extracellular electrical resistance R_E of the patient and deriving an extracellular water volume ECW of the patient using R_E.

5. The method according to claim 4 characterised in that it further comprises the step of deriving a mal-hydration water volume ECW_EX of the patient by using the extracellular water volume ECW.

6. The method according to claim 5 characterised in that it further comprises the steps of determining the total mass M of the patient and to derive the mal-hydration water volume ECW_EX by also using the total mass M.

7. The method according to claim 1 characterised in that it further comprises the step of deriving the masses M_AT of the first kind of tissue and M_LT of the second kind of tissue of the patient.

8. The method according to claim 1 characterised in that the first kind of tissue is adipose tissue and the second kind of tissue is lean tissue.

9. The method according to claim 8 characterised in that the lean tissue is defined by the tissue of the patient not being adipose tissue.

10. A device (10) for carrying out the method according to claim 1 comprising

a measurement unit (5), wherein the measurement unit comprises a bioimpedance device for determining an intracellular electrical resistance R_mix of the patient and

an evaluation unit (1) configured to derive the intracellular volume ICV using R_mix by taking into account that a cell of a first kind of tissue contributes differently to the electrical resistance R_mix of the intracellular volume ICV compared with a cell of a second kind of tissue.

11. The device according to claim 10 characterised in that the evaluation unit is a microprocessor unit (1) which in turn comprises a microprocessor program storage unit (1a), wherein in the microprocessor program storage unit (1a) a program for deriving the intracellular volume ICV using R_mix by taking into account that a cell of a first kind of tissue contributes differently to the electrical resistance R_mix of the intracellular volume ICV compared with a cell of a second kind of tissue is stored.

12. The device according to claim 11 characterised in that the program stored in the microprocessor storage unit (1a) also controls the measurement unit for determining the resistance R_mix.

13. The device according to claim 10 characterised in that the device further comprises input means (2) for entering an anthropometric measure X of the patient into the evaluation unit (1) and that the evaluation unit is configured of deriving the intracellular volume ICV using X.

14. The device according to claim 10 characterised in that the measurement unit (5) is also configured to determine an extracellular electrical resistance R_E of the patient and in that the evaluation unit (1) is configured to derive the extracellular water volume ECW using R_E.

15. The device according to claim 14 characterised in that the evaluation unit (1) is further configured to derive a mal-hydration water volume ECW_EX using the extracellular water volume ECW.

16. The device according to claim 15 characterised in that the device further comprises input means (5) for entering the total mass M of the patient into the evaluation unit (1) and that the evaluation unit is configured to derive the mal-hydration water volume ECW_EX using M.

17. The device according to claim 10 characterised in that the evaluation unit (1) is configured to derive the masses M_AT of the first kind of tissue and M_LT of the second kind of tissue of the patient.

18. The device according to claim 10 characterised in that the first kind of tissue is adipose tissue and the second kind of tissue is lean tissue.

19. The device according to claim 18 characterised in that the lean tissue is defined as the tissue of the patient not being adipose tissue.

20. The device according to claim 10 characterised in that it further comprises an output unit (9) linked to the evaluation unit (1) for outputting, preferably displaying, any data derived from the evaluation unit.

21. A computer program product characterised in that it comprises a storage medium on which a microprocessor program to be stored in the microprocessor program storage unit (1a) of the device (10) according to claim 11 is stored.