System and methods for processing analyte sensor data

• US 7,826,981 B2
• Filed: 01/18/2005
• Issued: 11/02/2010
• Est. Priority Date: 08/01/2003
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Goode, Paul V. Jr., Brauker, James H., Kamath, Apurv U.
• Primary Examiner(s): Nghiem; Michael P
• Application Number:
  US11/038,340
• Publication Number:
  US 20050187720A1
• Time in Patent Office: 2,114 Days
• Field of Search: 702/22, 702/23, 702/26, 702/27, 702/67, 702/68, 600/309, 600/345, 600/347, 600/365
• US Class Current: 702/23
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 2560/04 Constructional details of apparatus
• CPC Class Codes: A61B 2562/085 combined with means for recording calibration data
• CPC Class Codes: A61B 3/10 Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/1433 provided with locking means details of syringes A61M5/315
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• 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 5/150022 for capillary blood or interstitial fluid
• CPC Class Codes: A61B 5/4839 combined with drug delivery
• CPC Class Codes: A61B 5/743 Displaying an image simultaneously with additional graphical information, e.g. symbols, charts, function plots
• CPC Class Codes: G01N 33/48707 by electrical means G01N33/49, G01N33/493 take precedence
• 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 processing sensor analyte data, including initiating calibration, updating calibration, evaluating clinical acceptability of reference and sensor analyte data, and evaluating the quality of sensor calibration. During initial calibration, the analyte sensor data is evaluated over a period of time to determine stability of the sensor. The sensor may be calibrated using a calibration set of one or more matched sensor and reference analyte data pairs. The calibration may be updated after evaluating the calibration set for best calibration based on inclusion criteria with newly received reference analyte data. Fail-safe mechanisms are provided based on clinical acceptability of reference and analyte data and quality of sensor calibration. Algorithms provide for optimized prospective and retrospective analysis of estimated blood analyte data from an analyte sensor.

Claims

1. A continuous glucose sensor system, the system comprising:

a sensor configured to measure a glucose concentration in a host;

sensor electronics configured to process continuous glucose sensor data from the sensor; and

a user interface configured to display information associated with the continuous glucose sensor data, wherein the information comprises one or more prospectively calibrated glucose sensor values and a plurality of different graphical representations indicative of smoothed glucose trend information over a plurality of different predetermined time periods to provide a plurality of different resolutions of the smoothed glucose trend information, wherein the user interface is configured to selectively display the plurality of different graphical representations responsive to a user selection, wherein the smoothed glucose trend information comprises a plurality of time-spaced sensor values, wherein the sensor electronics are configured to smooth the plurality of time-spaced sensor values associated with a predetermined window of the continuous glucose sensor data, and wherein the user interface is configured to display sensor data or not based at least in part on a level of stability of the continuous glucose sensor data, wherein the level of stability is based at least in part on an evaluation of a sensor sensitivity associated with signal strength with respect to glucose concentration.

2. The system of claim 1, further comprising a blood glucose monitor configured to measure a reference glucose value.

3. The system of claim 2, wherein the user interface is further configured to selectively display the reference glucose value.

4. The system of claim 2, wherein the blood glucose monitor is integral with the user interface.

5. The system of claim 1, wherein information is selectively displayed on one or more screens viewable on the user interface.

6. The system of claim 1, wherein the user interface is configured for wireless communication with the sensor.

7. The system of claim 1, wherein the sensor electronics are configured to determine at least one of a hyperglycemic or hypoglycemic alarm.

8. The system of claim 1, wherein the sensor electronics are configured to process a sensor ID associated with the sensor.

9. The system of claim 1, wherein the sensor electronics are configured to wirelessly communicate with a reference glucose monitor.

10. The system of claim 1, wherein the user interface is configured to accept user input comprising information selected from the group consisting of mealtime, exercise, insulin administration, reference glucose values, and combinations thereof.

11. The system of claim 10, wherein the user interface is configured to display at least some of the user input.

12. The system of claim 1, wherein the user interface comprises a plurality of buttons configured to provide at least one action selected from the group consisting of toggle, menu selection, option selection, mode selection, and combinations thereof.

13. The system of claim 12, wherein the user interface further comprises a plurality of user selectable displays, and wherein the user selectable displays are configured to be selectively displayed in response to a press of one or more buttons.

14. The system of claim 1, wherein the different predetermined time periods comprise at least two time periods selected from the group consisting of one hour, three hours, and nine hours.

15. The system of claim 14, wherein the different predetermined time periods comprise at least three time periods selected from the group consisting of one hour, three hours, and nine hours.

16. The system of claim 1, wherein the plurality of different resolutions of glucose trend information comprise a plurality of different visual perspectives of a recent time period of the continuous glucose sensor data.

17. The system of claim 1, wherein the information further comprises directional information associated with the continuous glucose sensor data.

18. The system of claim 17, wherein the directional information comprises at least one of an arrow or angled line, and wherein the directional information is determined from the smoothed glucose trend information.

19. The system of claim 1, wherein the predetermined window of the continuous glucose sensor data comprises at least about 20 minutes of the continuous glucose sensor data.

20. The system of claim 19, wherein the predetermined window of the continuous glucose sensor data comprises at least about 40 minutes of the continuous glucose sensor data.

21. The system of claim 1, wherein the sensor electronics are configured to predict future glucose sensor values.

22. The system of claim 1, wherein the sensor electronics are configured to determine a clinical acceptability of the continuous glucose sensor data to display the one or more prospectively calibrated glucose sensor values on the user interface responsive to a predetermined clinical acceptability of the continuous glucose sensor data.

23. The system of claim 1, wherein the different graphical representations indicative of smoothed glucose trend information are represented by individual points.

24. The system of claim 1, wherein each of the different graphical representations indicative of smoothed glucose trend information comprise a line.

25. The system of claim 1, wherein the sensor electronics are configured to smooth the plurality of time-spaced sensor values such that the smoothed glucose trend information comprises time-delayed estimated values.

26. The system of claim 1, wherein the sensor electronics are further configured to compensate for time delay such that the displayed smoothed glucose trend information is not time-delayed.

27. The system of claim 1, wherein the system is configured to convert the continuous glucose sensor data from an analog signal to a digital signal.

28. A system for displaying continuous glucose sensor data, the system comprising:

a sensor configured to measure a glucose concentration in a host;

a processor module or sensor electronics configured to process continuous glucose sensor data from the sensor; and

a user interface configured to display information associated with the continuous glucose sensor data, wherein the information comprises one or more prospectively calibrated glucose sensor values and a plurality of different graphical representations indicative of smoothed glucose trend information over a plurality of different predetermined time periods to provide a plurality of different resolutions of the smoothed glucose trend information, wherein the user interface is configured to selectively display the plurality of different graphical representations responsive to a user selection, wherein the smoothed glucose trend information comprises a plurality of time-spaced sensor values, wherein the processor module or sensor electronics are configured to smooth the plurality of time-spaced sensor values associated with a predetermined window of the continuous glucose sensor data, and wherein the user interface is configured to display sensor data or not based at least in part on a level of stability of the continuous glucose sensor data, wherein the level of stability is based at least in part on an evaluation of a sensor sensitivity associated with signal strength with respect to glucose concentration;

wherein the processor module or sensor electronics are configured to receive reference glucose data from a reference glucose monitor;

wherein the processor module or sensor electronics are further configured to determine a level of clinical risk of a relative difference between the reference glucose data and time-corresponding smoothed sensor data; and

wherein the level of clinical risk is based at least in part on a value of the reference glucose data and a value of the smoothed sensor data.