System and methods for wireless body fluid monitoring

• US 9,357,932 B2
• Filed: 05/22/2015
• Issued: 06/07/2016
• Est. Priority Date: 09/14/2007
• Status: Expired due to Fees

• Current Assignee: Medtronic Monitoring, Inc. (Medtronic Plc)
• Original Assignee: Medtronic Monitoring, Inc. (Medtronic Plc)
• Inventors: Libbus, Imad, Bly, Mark J.
• Primary Examiner(s): TOWA, RENE T
• Application Number:
  US14/720,160
• Publication Number:
  US 20150250405A1
• Time in Patent Office: 382 Days
• Field of Search: 600/306, 600/372, 600/382, 600/393, 600/547, 600/554
• US Class Current: 1/1
• CPC Class Codes: A61B 2560/0412 Low-profile patch shaped housings
• CPC Class Codes: A61B 2562/0215 Silver or silver chloride containing
• CPC Class Codes: A61B 2562/043 in a linear array
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61B 5/0245 by using sensing means generating electric signals, i.e. ECG signals
• CPC Class Codes: A61B 5/0537 Measuring body composition by impedance, e.g. tissue hydration or fat content
• CPC Class Codes: A61B 5/259 using conductive adhesive means, e.g. gels
• CPC Class Codes: A61B 5/28 for electrocardiography [ECG]
• CPC Class Codes: A61B 5/282 Holders for multiple electrodes for introduction into the body A61B5/287
• CPC Class Codes: A61B 5/443 Evaluating skin constituents, e.g. elastin, melanin, water
• CPC Class Codes: A61B 5/6833 Adhesive patches
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure
• CPC Class Codes: G16H 40/67 for remote operation
• CPC Class Codes: G16H 50/30 for calculating health indices; for individual health risk assessment

Abstract

An adherent device to monitor a tissue hydration of a patient comprises an adhesive patch to adhere to a skin of the patient. A plurality of electrodes are connected to the patch and capable of electrically coupling to the patient. Circuitry is coupled to the plurality of electrodes to measure a tissue resistance of the patient at a first frequency and to detect a low frequency droop in the measured tissue resistance. In response to detected low frequency droop, the circuitry is configured to measure a tissue resistance of the patient at a second frequency that is lower than the first frequency to verify the detection of low frequency droop, and to temporarily suspend data collection based on the detection and verification of low frequency droop.

Claims

1. A method of monitoring a patient, the method comprising:

adhering an adhesive patch to a skin of the patient to couple a plurality of electrodes to the skin of the patient to form a skin-electrode interface;

measuring a plurality of tissue resistances of the patient at a first frequency with impedance circuitry coupled to the plurality of electrodes;

detecting, with the impedance circuitry, a low frequency droop in the tissue resistance measurements made at the first frequency;

measuring, with the impedance circuitry, a tissue resistance of the patient at a second frequency, wherein the second frequency is lower than the first frequency;

verifying, with the impedance circuitry, the detection of low frequency droop based on the tissue resistance measured at the second frequency; and

temporarily suspending data collection with the impedance circuitry based at least in part on the fact that the low frequency droop has been detected and verified.

2. The method of claim 1, wherein the first frequency is less than 100 kHz.

3. The method of claim 1, wherein the first frequency is less than 20 kHz.

4. The method of claim 1, wherein the second frequency is equal to about 2 kHz.

5. The method of claim 1, wherein low frequency droop is detected when the measured tissue resistances at the first frequency declines by a threshold amount.

6. The method of claim 5, wherein the threshold amount is a decline of more than 10%.

7. The method of claim 5, wherein the threshold amount is a decline of more than 20%.

8. The method of claim 1, further including calculating a change in patient body fluid based on the tissue resistance measured at the first frequency if no low frequency droop is detected.

9. An adherent device to monitor a tissue hydration of a patient, the device comprising:

an adhesive patch to adhere to a skin of the patient;

a plurality of electrodes connected to the patch and capable of electrically coupling to the patient; and

circuitry coupled to the plurality of electrodes to measure a plurality of tissue resistances of the patient at a first frequency and to detect a low frequency droop in the measured tissue resistances, wherein in response to detected low frequency droop, the circuitry is configured to measure a tissue resistance of the patient at a second frequency that is lower than the first frequency to verify the detection of low frequency droop, and to temporarily suspend data collection based on the detection and verification of low frequency droop.

10. The adherent device of claim 9, wherein the first frequency is less than 100 kHz.

11. The adherent device of claim 9, wherein the first frequency is less than 20 kHz.

12. The adherent device of claim 9, wherein the second frequency is equal to about 2 kHz.

13. The adherent device of claim 9, wherein the circuitry is configured to detect low frequency droop when the measured tissue resistances at the first frequency declines by a threshold amount.

14. The adherent device of claim 13, wherein the threshold amount is a decline of more than 10%.

15. The adherent device of claim 13, wherein the threshold amount is a decline of more than 20%.

16. The adherent deice of claim 9, wherein the circuitry is further configured to calculate a change in patient body fluid based on the tissue resistance measured at the first frequency if no low frequency droop is detected.