USE OF ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY (EIS) IN INTELLIGENT DIAGNOSTICS

• US 20150164387A1
• Filed: 08/22/2014
• Published: 06/18/2015
• Est. Priority Date: 12/16/2013
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: VARSAVSKY, ANDREA, MILLER, MICHAEL E., LIANG, BRADLEY C.
• Granted Patent: US 10,638,947 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 5/0537 Measuring body composition by impedance, e.g. tissue hydration or fat content
• CPC Class Codes: A61B 5/0538 invasively, e.g. using a catheter
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1468 using chemical or electrochemical methods, e.g. by polarographic means A61B5/1486 takes precedence
• CPC Class Codes: A61B 5/1473 invasive, e.g. introduced into the body by a catheter A61B5/1482 takes precedence
• 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 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: A61B 5/6849 in combination with a needle set
• CPC Class Codes: A61B 5/7221 Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 take precedence
• CPC Class Codes: A61B 5/7246 using correlation, e.g. template matching or determination of similarity
• CPC Class Codes: A61M 2005/1726 the body parameters being measured at, or proximate to, the infusion site
• CPC Class Codes: A61M 5/14244 adapted to be carried by the patient, e.g. portable on the body
• CPC Class Codes: A61M 5/14276 specially adapted for implantation
• CPC Class Codes: A61M 5/1582 Double lumen needles
• CPC Class Codes: G01N 27/026 Dielectric impedance spectroscopy electrochemical impedance spectroscopy for measuring corrosion G01N17/02

Abstract

Electrochemical Impedance Spectroscopy (EIS) is used in conjunction with continuous glucose monitors and continuous glucose monitoring (CGM) to enable in-vivo sensor calibration, gross (sensor) failure analysis, and intelligent sensor diagnostics and fault detection. An equivalent circuit model is defined, and circuit elements are used to characterize sensor behavior.

Claims

1. A method for determining the age of a sensor, the method comprising:

performing an electrochemical impedance spectroscopy (EIS) procedure prior to initialization of said sensor;

generating a Nyquist plot based on the output of said EIS procedure; and

based on a lower-frequency Nyquist slope, determining whether the sensor is new.

2. The method of claim 1, wherein said determination is based on comparison of the lower-frequency Nyquist slope to a threshold slope.

3. The method of claim 2, wherein the threshold slope is 3.

4. A method of differentiating between different glucose sensors, the method comprising:

performing an electrochemical impedance spectroscopy (EIS) procedure for said sensor;

generating a Nyquist plot based on the output of said EIS procedure; and

based on said Nyquist plot, identifying one or more of said different sensors.

5. The method of claim 4, wherein said identification is made based on the lower-frequency Nyquist slope length.

6. The method of claim 5, wherein said length is calculated as the Cartesian distance between EIS at 0.105 Hz and 1 Hz.