Method for measuring the degree of edema and apparatus using the same

• US 6,714,813 B2
• Filed: 01/16/2001
• Issued: 03/30/2004
• Est. Priority Date: 01/21/2000
• Status: Active Grant

• Current Assignee: Tanita Corporation (Tanita)
• Original Assignee: Tanita Corporation (Tanita)
• Inventors: Fukuda, Yoshinori, Ishigooka, Maki
• Primary Examiner(s): FUQUA, SHAWNTINA T
• Application Number:
  US09/759,320
• Publication Number:
  US 20010020138A1
• Time in Patent Office: 1,169 Days
• Field of Search: 600/547, 600/300, 600/372, 600/393, 600/399, 600/548, 600/544, 600/322
• 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 5/4869 Determining body composition

Abstract

Disclosed is an edema measuring method comprising the steps of: putting at least two pairs of electrodes on different locations selected in the body; making an alternating current to flow in the body via one pair of electrodes; measuring voltage appearing between the other pair of electrodes; calculating impedance on the basis of the supplied alternating current and the measured voltage; and calculating an index value representing the degree of edema on the basis of the impedance. Also, an apparatus using the method is disclosed.

Claims

1. An apparatus which is capable of measuring a degree of edema of a person characterized in that it comprises:

at least two pairs of electrodes to be put on selected locations in the body of the person;

an alternating current supplying device which supplies alternating current to one pair of the electrodes;

a voltage measuring device which measures the voltage appearing between the other pair of electrodes;

an arithmetic unit which calculates impedance on the basis of the supplied alternating current and the determined voltage, and calculates an index value representing the degree of edema on the basis of the so calculated impedance; and

an estimating device which determines the degree of edema the person has from the calculated index value of edema and a body weight or fat free mass of the person.

5. An apparatus according to any of claims 1 to 4, wherein:

the alternating current supplying device supplies a plurality of alternating currents of different frequencies to said one pair of electrodes; and

the voltage measuring device measures the voltage appearing between said the other pair of electrodes each time an alternating current of selected frequency is supplied, allowing the arithmetic unit to calculate the impedance values on the basis of each alternating current and corresponding voltage and to calculate the index value of edema on the basis of the so calculated impedance values.

6. An apparatus according to claims 1 to 4, wherein the index value of edema includes a ratio of intra-cellular water to extra-cellular water or inversely, or a ratio of extra-cellular water to total body water or inversely.

7. An apparatus according to any of claims 1 to 4, wherein it further comprises a phase difference measuring device which measures the phase difference between the supplied alternating current and the measured voltage, whereby the arithmetic device may calculate the index value of edema on the basis of the phase difference and the resistance value calculated from the alternating current and the voltage when an alternating current of single frequency is supplied to said one pair of electrodes.

8. An apparatus according to any of claims 1 to 4, wherein it further comprises an estimating device which determines the stage of edema of the person based on the calculated index value of edema and other relevant data.

9. An apparatus according to claim 1, wherein the index value of edema is a ratio of intra-cellular water to extra-cellular water, and wherein said estimating device determines that the person should reduce food intake because an excessive amount of food has been taken when the ratio decreases and the body weight increases.

10. An apparatus according to claim 1, wherein the index value of edema is a ratio of intra-cellular water to extra-cellular water, and wherein said estimating device determines that extra attention to malnutrition is required due to an insufficient amount of food being taken when the ratio decreases and the body weight remains unchanged.

11. An apparatus according to claim 1, wherein the index value of edema is a ratio of intra-cellular water to extra-cellular water, and wherein said estimating device determines that the person takes an appropriate amount of food when the ratio and the body weight remain unchanged.

12. An apparatus according to any of claims 1, 3, 4, 9, 10 or 11, wherein said estimating device further determines whether an amount of food has been regulated well based on the calculated index value of edema and other relevant data.

14. An apparatus according to any of claims 1 to 4, wherein it further comprises a second estimating device which determines the stage of edema of the person by comparing the calculated index value of edema with a reference value which represents an index value of edema of a person in normal physical condition.

15. An apparatus according to claim 14, wherein it further comprises a third estimating device which determines the stage of edema of the person by comparing the index value of edema with an average of the index values of edema previously calculated.

16. An apparatus according to claim 15, wherein it further comprises a display which shows the calculated index value of edema and/or the determined stage of edema of the person.

17. An apparatus according to claim 16, wherein said display shows a series of index values of edema previously calculated, representing how the index value of edema has varied.

18. An apparatus according claim 17, wherein said display shows 10 to 15 averages of index values of edema, each average representing the average of the index values calculated in each of 10 to 15 equi-divisions into which the length of time spanning from a first measurement to the latest measurement is divided.

19. An apparatus according to claim 18, wherein it further comprises a communication device which transmits to other data processors at least one piece of information selected among measured voltage , measured phase difference, some derivations therefrom, the calculated index value of edema, a determined stage of edema of the person, and personal particulars of the person.

20. An apparatus according to claim 19, wherein said communication device receives the results of a given process executed on said information in said other data processors.

21. An apparatus according to claim 20, wherein it further comprises a writing device which writes one piece of information selected among measured voltage, measured phase difference, some derivations therefrom, the calculated index value of edema, a determined stage of edema of the person, and personal particulars of the person.

2. An apparatus which is capable of measuring a degree of edema of a person characterized in that it comprises:

at least two pairs of electrodes to be put on selected locations in the body of the person;

an alternating current supplying device which supplies alternating current to one pair of the electrodes;

a voltage measuring device which measures the voltage appearing between the other pair of electrodes;

an arithmetic unit which calculates impedance on the basis of the supplied alternating current and the determined voltage, and calculates a preset index value representing the degree of edema on the basis of the so calculated impedance; and

an estimating device which determines a stage of edema of the person by comparing the preset index value of edema with an average of index values of edema previously calculated.

3. An apparatus which is capable of measuring a degree of edema of a person characterized in that it comprises:

at least two pairs of electrodes to be put on selected locations in the body of the person;

an alternating current supplying device which supplies alternating current to one pair of the electrodes;

a voltage measuring device which measures the voltage appearing between the other pair of electrodes;

an arithmetic unit which calculates impedance on the basis of the supplied alternating current and the determined voltage, and calculates an index value representing the degree of edema on the basis of the so calculated impedance; and

a display which shows a series of index values of edema previously calculated, representing how the index value of edema has varied.

13. An apparatus according to claim 3, wherein said other relevant data is a body weight or fat free mass of the person.

4. An apparatus which is capable of measuring a degree of edema of a person characterized in that is comprises:

at least two pairs of electrodes to be put on selected locations in the body of the person;

an alternating current supplying device which supplies alternating current to one pair of the electrodes;

a voltage measuring device which measures the voltage appearing between the other pair of electrodes;

an arithmetic unit which calculates impedance on the basis of the supplied alternating current and the determined voltage, and calculates an index value representing the degree of edema on the basis of the so calculated impedance; and

a communication device which transmits to other data processors at least one piece of information selected among measured voltage, measured phase difference, some derivations therefrom, the calculated index value of edema, a determined stage of edema of the person, and personal particulars of the person.