Glucose sensor signal stability analysis

• US 9,101,310 B2
• Filed: 08/30/2013
• Issued: 08/11/2015
• Est. Priority Date: 06/23/2010
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Luo, Ying, Gottlieb, Rebecca K., Ramachandran, Meena, Chiu, Chia-Hung, Dangui-Patel, Nandita, Kremliovsky, Michael, Rose, Jefferson
• Primary Examiner(s): TSAI, CAROL S W
• Application Number:
  US14/015,937
• Publication Number:
  US 20140000338A1
• Time in Patent Office: 711 Days
• Field of Search: 702/19, 702/179, 702/182, 702/85, 702/23, 702/32, 702/90, 702/91, 702/189, 702/183, 600/345, 600/347, 600/365
• US Class Current: 1/1
• CPC Class Codes: A61B 5/0017 transmitting optical signals transmission by light H04B10/00
• CPC Class Codes: A61B 5/002 Monitoring the patient using a local or closed circuit, e.g. in a room or building A61B5/0017 takes precedence
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1486 using enzyme electrodes, e.g. with immobilised oxidase
• 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 5/7207 of noise induced by motion artifacts
• CPC Class Codes: G01N 33/66 involving blood sugars, e.g. galactose

Abstract

Disclosed are methods, apparatuses, etc. for glucose sensor signal stability analysis. In certain example embodiments, a series of samples of at least one sensor signal that is responsive to a blood glucose level of a patient may be obtained. Based at least partly on the series of samples, at least one metric may be determined to assess an underlying trend of a change in responsiveness of the at least one sensor signal to the blood glucose level of the patient over time. A reliability of the at least one sensor signal to respond to the blood glucose level of the patient may be assessed based at least partly on the at least one metric assessing an underlying trend. Other example embodiments are disclosed herein.

Claims

1. A method comprising:

obtaining a series of samples of at least one sensor signal is responsive to a blood glucose level of a patient;

determining, based at least partly on the series of samples, at least one metric assessing an underlying trend of a change in responsiveness of the at least one sensor signal to the blood glucose level of the patient over time, wherein said determining comprises;

iteratively updating a trend estimation at multiple samples of the series of samples of the at least one sensor signal based at least partly on a trend estimation at a previous sample and a growth term; and

assessing a reliability of the at least one sensor signal to respond to the blood glucose level of the patient based at least partly on the at least one metric assessing an underlying trend.

2. The method of claim 1, further comprising:

generating an alert signal responsive to a comparison of the at least one metric assessing an underlying trend with at least one predetermined threshold.

3. The method of claim 1, wherein said assessing comprises:

comparing the at least one metric assessing an underlying trend with at least a first predetermined threshold and a second predetermined threshold.

4. The method of claim 1, further comprising:

acquiring the at least one sensor signal from one or more subcutaneous glucose sensors, wherein the at least one metric assessing an underlying trend reflects an apparent reliability of the at least one sensor signal that is acquired from the one or more subcutaneous glucose sensors.

5. The method of claim 1, further comprising:

altering an insulin infusion treatment for the patient responsive at least partly to the assessed reliability of the at least one sensor signal.

6. The method of claim 1, wherein said determining comprises:

producing the at least one metric assessing an underlying trend using a slope of a linear regression that is derived at least partly from the series of samples of the at least one sensor signal.

7. An apparatus comprising:

a controller to obtain a series of samples of at least one sensor signal that is responsive to a blood glucose level of a patient, said controller comprising one or more processors to;

determine, based at least partly on the series of samples, at least one metric assessing an underlying trend of a change in responsiveness of the at least one sensor signal to the blood glucose level of the patient over time; and

assess a reliability of the at least one sensor signal to respond to the blood glucose level of the patient based at least partly on the at least one metric assessing an underlying trend;

wherein said controller is capable of assessing by;

comparing the at least one metric assessing an underlying trend with at least a first predetermined threshold and a second predetermined threshold; and

ascertaining at least one value indicating a severity of divergence by the at least one sensor signal from the blood glucose level of the patient over time based at least partly on the at least one metric assessing an underlying trend, the first predetermined threshold, and the second predetermined threshold.

8. The apparatus of claim 7, wherein said One or more processors of said controller are further to:

generate an alert signal responsive to a comparison of the at least one metric assessing an underlying trend with at least one predetermined threshold.

9. The apparatus of claim 7, wherein said one or more processors of said controller are further to:

acquire the at least one sensor signal from one or more subcutaneous glucose sensors, wherein the at least one metric assessing an underlying trend reflects an apparent reliability of the at least one sensor signal that is acquired from the one or more subcutaneous glucose sensors.

10. The apparatus of claim 7, wherein said one or more processors of said controller are further to:

alter an insulin infusion treatment for the patient responsive at least partly to the assessed reliability of the at least one sensor signal.

11. The apparatus of claim 7, wherein said controller is capable of determining by:

producing the at least one metric assessing an underlying trend using a slope of a linear regression that is derived at least partly from the series of samples of the at least one sensor signal.

12. The apparatus of claim 11, wherein said one or more processors of said controller are further to:

transform the series of samples of the at least one sensor signal to derive a monotonic curve, wherein said controller is capable of producing the at least one metric assessing an underlying trend by calculating the slope of the linear regression, the linear regression being derived at least partly from the monotonic curve.

13. The apparatus of claim 7, wherein said controller is capable of determining by:

decomposing the at least one sensor signal as represented by the series of samples using at least one empirical mode decomposition and one or more spline functions to remove relatively higher frequency components from the at least one sensor signal.

14. The apparatus of claim 7, wherein said controller is capable of determining by:

decomposing the at least one sensor signal as represented by the series of samples using at least one discrete wavelet transform; and

reconstructing a smoothed signal from one or more approximation coefficients resulting from the at least one discrete wavelet transform.

15. The apparatus of claim 7, wherein said controller is capable of determining by:

iteratively updating a trend estimation at multiple samples of the series of samples of the at least one sensor signal based at least partly on a trend estimation at a previous sample and a growth term.

16. An article comprising:

at least one storage medium having stored thereon instructions executable by one or more processors to;

obtain a series of samples of at east one sensor signal that is responsive to a blood glucose level of a patient;

determine, based at least partly on the series of samples, at least one metric assessing an underlying trend of a change in responsiveness of the at least one sensor signal to the blood glucose level of the patient over time; and

assess a reliability of the at least one sensor signal to respond to the blood glucose level of the patient based at least partly on the at least one metric assessing an underlying trend;

wherein to determine comprises to;

decompose the at least one sensor signal as represented by the series of samples using at least one empirical mode decomposition and one or more spline functions to remove relatively higher frequency components from the at least one sensor signal.

17. The article of claim 16, wherein said instructions are further executable by said one or more processors to generate an alert signal responsive to a comparison of the at least one metric assessing an underlying trend with at least one predetermined threshold.