US 7,985,330 B2Granted

Method and system for detecting age, hydration, and functional states of sensors using electrochemical impedance spectroscopy

AssigneeMedtronic MiniMed, Inc.

InventorsLu Wang, Rajiv Shah, Kenneth W. Cooper, Richard K. Yoon, Helen Lee

Life of this patent

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Abstract

A method and program prevents a user from bypassing a limit placed on a specified operating life of a sensor by disconnecting and reconnecting the sensor. The present invention checks a characteristic of the sensor to see if the sensor is used prior to the connection of the sensor, and rejects the sensor if the sensor is determined to have been used before. The process of checking the characteristic of the sensor involves performing an Electrochemical Impedance Spectroscopy (EIS) procedure and calculating an impedance value. The impedance value can be compared to various threshold values for a variety of purposes including the determination of age, condition, hydration, and stabilization of the sensor.

Claims7

Dependent claims

A method of using a sensor placed within a subcutaneous insertion site, comprising:

(a) connecting a sensor having at least two electrodes to sensor electronics;
(b) initiating a stabilization procedure for the sensor via the sensor electronics, the stabilization procedure performing a plurality of anodic-cathodic cycles between the plurality of electrodes;
(c) verifying if a hydration time threshold has elapsed if the sensor is not operating within specified parameters;
(d) initiating a hydration assist procedure, the hydration assist procedure transmitting a signal for the sensor electronics to apply voltage pulses to the sensor;
(e) generating sensor signals when the sensor is within the operational window;
(f) performing an EIS procedure between the electrodes, the EIS procedure includes using a glucose oxidase enzyme to catalyze a reaction between the electrodes;
(g) calculating an impedance value between the electrodes;
and
(h) comparing the impedance value against a threshold to determine if the sensor has aged beyond the specified sensor life.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 11/618,183Filed 29 Dec 2006 · continuation in part
Priority: 30 Dec 2005
Published: US 2007/0169533 A126 Jul 2007
Granted: 26 Jul 2011
Term ends: Not estimatedThe source records don’t support an estimate.

Classification13 codes

A61B 5/14865
Using enzyme electrodes, e.g. with immobilised oxidase: invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors
A61B 5/14532
Measuring characteristics of blood in vivo, e.g. gas concentration or pH-value ; Measuring characteristics of body fluids or tissues, e.g.…: for…
A61B 5/1495
Measuring characteristics of blood in vivo, e.g. gas concentration or pH-value ; Measuring characteristics of body fluids or tissues, e.g.…:…
A61B 5/15003
Source of blood: for venous or arterial blood

Family

Application11/322,977Parent of this continuation-in-part · filed 30 Dec 2005
Application11/323,242Parent of this continuation-in-part · filed 30 Dec 2005
US 2007/0170073 A1Pre-grant publication · published 26 Jul 2007
US 2007/0169533 A1Published application
US 2007/0173712 A1Published application
US 7,985,330 B2This patent

From the US filing history. Foreign family members aren’t listed.