Glucose sensor signal reliability analysis

• US 9,033,878 B2
• Filed: 10/26/2011
• Issued: 05/19/2015
• Est. Priority Date: 10/28/2010
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Liang, Bradley, Cooper, Kenneth W., Gautham, Raghavendhar, Shah, Rajiv
• Primary Examiner(s): Kahelin, Michael
• Assistant Examiner(s): Alter, Mitchell E
• Application Number:
  US13/282,228
• Publication Number:
  US 20120108935A1
• Time in Patent Office: 1,301 Days
• Field of Search: 600/365
• US Class Current: 600/365
• CPC Class Codes: A61B 2560/0276 Determining malfunction
• CPC Class Codes: A61B 5/14503 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors A61B5/1459, A61B5/1464, A61B5/1473, A61B5/1482, A61B5/14865 take precedence
• CPC Class Codes: A61B 5/1451 for interstitial fluid
• 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 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: A61B 5/4839 combined with drug delivery
• 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 5/746 Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms alarms per se G08B
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 2230/201 Glucose concentration
• CPC Class Codes: A61M 5/14248 of the skin patch type
• CPC Class Codes: A61M 5/1723 using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00

Abstract

Disclosed are methods, apparatuses, etc. for glucose sensor signal reliability analysis.

Claims

1. An apparatus comprising:

a glucose sensor to obtain measurements responsive to a presence of glucose in a fluid; and

a processor to;

detect a change in responsiveness of said glucose sensor to said presence of glucose in a fluid based, at least in part, on an application of one or more thresholds to one or more sensitivity metrics,

at least one of said sensitivity metrics being computed based, at least part, on said measurements, wherein said change in responsiveness of said glucose sensor to the presence of glucose in said fluid is detected by;

defining a sequence of windows in time;

for at least one of said windows, computing a measure of dispersion of said rate of change; and

determining at least one of said sensitivity metrics based, at least in part, on said computed measure of dispersion;

wherein said at least one of said sensitivity metrics are detected by determining said at least one of said sensitivity metrics based, at least in part, on a ratio of said computed measure of dispersion and a mean value of glucose sensor measurements obtained in said at least one of said windows.

2. The apparatus of claim 1, wherein said change in responsiveness comprises a decrease in sensitivity of said glucose sensor to the presence of glucose in said fluid.

3. The apparatus of claim 1, wherein said computed measure of dispersion of said rate of change comprises a variance of said rate of change.

4. An article comprising:

a non-transitory storage medium having machine-readable instructions stored thereon which are executable by a special purpose computing apparatus to;

obtain a plurality of glucose sensor measurements at a glucose sensor over a time interval; and

detect a change in responsiveness of said glucose sensor to a presence of glucose in a fluid based, at least in part, on an application of one or more thresholds to one or more sensitivity metrics, at least one of said sensitivity metrics being based, at least in part, on said glucose sensor measurements, wherein said change in responsiveness of said glucose sensor to the presence of glucose in said fluid is detected by;

defining a sequence of windows in time;

for at least one of said windows, computing a measure of dispersion of said rate of change; and

determining at least one of said sensitivity metrics based, at least in part, on said computed measure of dispersion;

wherein said at least one of said sensitivity metrics are detected by determining said at least one of said sensitivity metrics based, at least in part, on a ratio of said computed measure of dispersion and a mean value of glucose sensor measurements obtained in said at least one of said windows.

5. The article of claim 4, wherein said change in responsiveness comprises a decrease in sensitivity of said glucose sensor to the presence of glucose in said fluid.

6. The article of claim 4, wherein said computed dispersion of said rate of change comprises a variance of said rate of change.

7. An apparatus comprising:

means for obtaining a plurality of glucose sensor measurements at a glucose sensor over a time interval; and

means for detecting a change in responsiveness of said glucose sensor to a presence of glucose in a fluid based, at least in part, on an application of one or more thresholds to one or more sensitivity metrics, at least one of said sensitivity metrics being based, at least in part, on said glucose sensor measurements, wherein said means for detecting a change in responsiveness of said glucose sensor to the presence of glucose in said fluid detects said change in responsiveness by defining a sequence of windows in time;

for at least one of said windows, computing a dispersion of said rate of change; and

determining at least one of said sensitivity metrics based, at least in part, on said computed dispersion;

wherein said at least one of said sensitivity metrics are detected by determining said at least one of said sensitivity metrics based, at least in part, on a ratio of said computed dispersion and a mean value of glucose sensor measurements obtained in said at least one of said windows.