SYSTEM AND METHOD FOR DETERMINING THE POINT OF HYDRATION AND PROPER TIME TO APPLY POTENTIAL TO A GLUCOSE SENSOR

• US 20120088996A1
• Filed: 12/16/2011
• Published: 04/12/2012
• Est. Priority Date: 12/30/2005
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Shah, Rajiv, Soundararajan, Gopikrishnan, Vejella, Ratnakar, COOPER, KENNETH W., Choy, David Y.
• Granted Patent: US 8,608,924 B2
• Time in Patent Office: Days
• US Class Current: 600/345
• CPC Class Codes: A61B 17/3468 for implanting or removing devices, e.g. prostheses, implants, seeds, wires devices for implanting seeds A61M37/0069
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14865 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors
• CPC Class Codes: A61B 5/6848 Needles
• CPC Class Codes: A61B 5/6849 in combination with a needle set
• CPC Class Codes: G01N 27/3271 Amperometric enzyme electrodes for analytes in body fluids, e.g. glucose in blood amperometry per se G01N27/49; aspects concerning the enzyme reagent C12Q1/001

Abstract

According to an embodiment of the invention, a method of determining hydration of a sensor having a plurality of electrodes is disclosed. In particular embodiments, the method couples a sensor electronics device to the sensor and measures the open circuit potential between at least two of the plurality of electrodes. Then, the open circuit potential measurement is compared to a predetermined value. In some embodiments, the plurality of electrodes includes a working electrode, a reference electrode, and a counter electrode. In still further embodiments, the open circuit potential between the working electrode and the reference electrode is measured. In other embodiments, the open circuit potential between the working electrode and the counter electrode is measured. In still other embodiments, the open circuit potential between the counter electrode and the reference electrode is measured.

Claims

1. A system for determining the point of hydration of a sensor, the system comprising:

a sensor, the sensor including a plurality of electrodes to be placed percutaneously or subcutaneously at a selected site in the body of a user; and

a sensor electronics device, the sensor electronics device being operably coupled to the sensor and including a hydration detection circuit,

wherein the hydration detection circuit measures successive open circuit potential values between at least two of the plurality of electrodes, calculates a rate of change of the measured open circuit potential values as the change over time between an open circuit potential value measured earlier in time and an open circuit potential value measured later in time, compares the open circuit potential values and the calculated rate of change to respective predetermined thresholds, determines that the point of hydration of the sensor has been reached if said predetermined thresholds are met, repeats said measurement, calculation, and comparison over a specified period of time if said predetermined thresholds are not met, and if said predetermined thresholds are not met after the specified period of time has been exceeded, determines that the sensor will not hydrate and notifies the user to replace the sensor.

2. The system of claim 1, wherein the plurality of electrodes includes a working electrode, a reference electrode, and a counter electrode.

3. The system of claim 2, wherein the open circuit potential between the working electrode and the reference electrode is measured.

4. The system of claim 2, wherein the open circuit potential between the working electrode and the counter electrode is measured.

5. The system of claim 2, wherein the open circuit potential between the counter electrode and the reference electrode is measured.

6. The system of claim 2, wherein the open circuit potential between the working electrode and the reference electrode is measured, and wherein the open circuit potential between the counter electrode and the reference electrode is measured.

7. The system of claim 2, wherein the open circuit potential between the working electrode and the counter electrode is measured and wherein the open circuit potential between the counter electrode and the reference electrode is measured.

8. The system of claim 2, wherein the open circuit potential between the working electrode and the reference electrode is measured, and wherein the open circuit potential between the working electrode and the counter electrode is measured, and wherein the open circuit potential between the counter electrode and the reference electrode is measured.

9. A program code storage device, comprising:

program code storage media; and

machine-readable program code, stored on the program code storage media, the machine-readable program code including instructions, which when executed cause a processor for a sensor electronics device that is operably coupled to a sensor having a plurality of electrodes to;

receive measurements of successive open circuit potential values between at least two of the plurality of electrodes;

calculate the rate of change of the measured open circuit potential values as the change over time between an open circuit potential value measured earlier in time and an open circuit potential value measured later in time;

compare the open circuit potential values and the calculated rate of change to respective predetermined thresholds;

determine that the sensor is ready for use if said predetermined thresholds are met;

repeat, over a specified period of time, the measuring, calculating, and comparing steps if said predetermined thresholds are not met; and

if said predetermined thresholds are not met after the specified period of time has been exceeded, determine that the sensor is not useable.

10. The program code storage device of claim 9, wherein the plurality of electrodes includes a working electrode, a reference electrode, and a counter electrode.

11. The program code storage device of claim 10, wherein said measurements are for open circuit potential values between the working electrode and the reference electrode.

12. The program code storage device of claim 10, wherein said measurements are for open circuit potential values between the working electrode and the counter electrode.

13. The program code storage device of claim 10, wherein said measurements are for open circuit potential values between the counter electrode and the reference electrode.

14. The program code storage device of claim 10, wherein said measurements are for open circuit potential values between the working electrode and the reference electrode and between the counter electrode and the reference electrode.

15. The program code storage device of claim 10, wherein said measurements are for open circuit potential values between the working electrode and the counter electrode and between the counter electrode and the reference electrode.

16. The program code storage device of claim 10, wherein said measurements are for open circuit potential values between the working electrode and the reference electrode, between the working electrode and the counter electrode, and between the counter electrode and the reference electrode.