Systems and methods for replacing signal artifacts in a glucose sensor data stream

• US 9,510,782 B2
• Filed: 04/04/2012
• Issued: 12/06/2016
• Est. Priority Date: 08/22/2003
• Status: Expired due to Term

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Kamath, Apurv Ullas, Brauker, James H., Mahalingam, Aarthi, Li, Ying
• Primary Examiner(s): Jiang, Christian
• Application Number:
  US13/439,701
• Publication Number:
  US 20120203467A1
• Time in Patent Office: 1,707 Days
• Field of Search: 600/345, 600/347, 600/365
• US Class Current: 1/1
• CPC Class Codes: A61B 2560/0252 using ambient temperature
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61B 5/145 Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissuemeasuring of blood pressure or blood flow A61B5/02; non-radiation detecting or locating of foreign bodies in blood A61B5/06
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14539 for measuring pH
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 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 5/6848 Needles
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7225 Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation A61B5/30, A61B5/316 take precedence; transformers for specific applications H01F38/00; amplifiers H03F
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems
• CPC Class Codes: Y02A 90/10 Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Abstract

Systems and methods for minimizing or eliminating transient non-glucose related signal noise due to non-glucose rate limiting phenomenon such as interfering species, ischemia, pH changes, temperatures changes, known or unknown sources of mechanical, electrical and/or biochemical noise, and the like. The system monitors a data stream from a glucose sensor and detects signal artifacts that have higher amplitude than electronic or diffusion-related system noise. The system processes some or the entire data stream continually or intermittently based at least in part on whether the signal artifact event has occurred.

Claims

1. A method for a continuous analyte monitoring system to output estimated analyte values generated using a continuous analyte sensor, the method comprising:

receiving sensor data from a continuous analyte sensor for a time period;

determining in substantially real-time, using a processor module, a first level of reliability of the continuous analyte sensor based on a first portion of the sensor data, wherein the first level of reliability is selected from a plurality of predetermined levels of reliability;

estimating, using the processor module, at least one analyte value for a first future time period based at least in part on the first portion of the sensor data;

turning on or maintaining outputting, using the processor module, the estimated at least one analyte value for the future time period based on the determined first level of reliability;

determining in substantially real-time, using the processor module, a second level of reliability of the continuous analyte sensor based on a second portion of the sensor data, wherein the second level of reliability is selected from the plurality of predetermined levels of reliability;

estimating, using the processor module, at least another analyte value for a second future time period based at least in part on the second portion of the sensor data; and

turning off outputting, using the processor module, the estimated at least another analyte value for the second future time period based on the determined second level of reliability,

wherein the first level of reliability indicates a higher level of reliability than the second level of reliability.

2. The method of claim 1, wherein the determining of the first or the second level of reliability comprises evaluating a rate of change.

3. The method of claim 1, wherein the determining of the first or the second level of reliability comprises performing a first derivative analysis or a second derivative analysis.

4. The method of claim 1, wherein the determining of the first or the second level of reliability comprises determining a level of confidence.

5. The method of claim 1, wherein the estimating is not performed responsive to the first or the second level of reliability failing a criterion.

6. The method of claim 1, wherein the determining of the first or the second level of reliability comprises determining a residual associated with the corresponding first or second portion of the sensor data.

7. The method of claim 1, wherein the first or the second level of reliability is selected from three or more predetermined levels of reliability.

8. The method of claim 1, further comprising triggering an alarm responsive to the at least one analyte value meeting one or more predetermined criteria.

9. The method of claim 1, wherein the at least one analyte value for the first future time period comprises a projected glucose value.

10. The method of claim 9, further comprising providing information for controlling an insulin pump.

11. The method of claim 10, wherein the information comprises the projected glucose value.

12. The method of claim 10, wherein the information comprises an amount or timing associated with insulin delivery using the insulin pump based on the projected glucose value.

13. The method of claim 10, wherein the information is based on the first level of reliability.

14. The method of claim 10, wherein the information comprises the first level of reliability.

15. A system for estimating an analyte value from a continuous analyte sensor, the system comprising:

a sensor data receiving module configured to receive a data stream from a continuous analyte sensor for a time period; and

a processor module configured to determine a first level of reliability of the continuous analyte sensor based on a first portion of the data stream, wherein the first level of reliability is selected from a plurality of predetermined levels of reliability, wherein the processor module is configured to estimate at least one analyte value for a first future time period based at least in part on the first portion of the data stream, and turn on or maintain outputting of the estimated at least one analyte value for the first future time period based on the determined first level of reliability, wherein the processor is configured to determine a second level of reliability of the continuous analyte sensor based on a second portion of the data stream, wherein the second level of reliability is selected from the plurality of predetermined levels of reliability, wherein the processor module is configured to estimate at least another analyte value for a second future time period based at least in part on the second portion of the data stream, and turn off outputting of the estimated at least another analyte value for the second future time period based on the determined second level of reliability, and wherein the first level of reliability indicates a higher level of reliability than the second level of reliability.

16. The system of claim 15, wherein the processor module is configured to determine the first level of reliability or the second level of reliability based on a rate of change of the corresponding first portion or the second portion of the data stream.

17. The system of claim 15, wherein the processor module is configured to determine the first level of reliability or the second level of reliability by performing a first derivative analysis or a second derivative analysis.

18. The system of claim 15, wherein the processor module is configured to determine the first level of reliability or the second level of reliability by determining a level of confidence associated with the corresponding data stream.

19. The system of claim 15, wherein the processor module is configured to not estimate the at least one analyte value or the at least another analyte value when the first level of reliability or the second level of reliability fails a criterion.

20. The system of claim 15, wherein the processor module is configured to determine the first level of reliability or the second level of reliability based on a residual associated with the corresponding data stream.

21. The system of claim 15, wherein the plurality of levels of reliability comprises three or more predetermined levels of reliability.

22. The system of claim 15, wherein the processor module is configured to trigger an alarm responsive to the at least one analyte value meeting one or more predetermined criteria.

23. The system of claim 15, wherein the at least one analyte value for the first future time period comprises a projected glucose value.

24. The system of claim 23, wherein the processor module is configured to provide information for controlling an insulin pump.

25. The system of claim 24, wherein the information comprises the projected glucose value.

26. The system of claim 24, wherein the information comprises an amount or timing associated with insulin delivery using the insulin pump based on the projected glucose value.

27. The system of claim 24, wherein the information is based on the first level of reliability.

28. The system of claim 24, wherein the information comprises the first level of reliability.