Signal processing for continuous analyte sensor

• US 9,498,155 B2
• Filed: 10/16/2008
• Issued: 11/22/2016
• Est. Priority Date: 12/09/2003
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Brauker, James H., Carr-Brendel, Victoria E., Goode, Paul V., Kamath, Apurv Ullas, Thrower, James P., Xavier, Ben, Simpson, Peter C., Tapsak, Mark A.
• Primary Examiner(s): JANG, CHRISTIAN YONGKYUN
• Application Number:
  US12/253,125
• Publication Number:
  US 20090043525A1
• Time in Patent Office: 2,959 Days
• Field of Search: 600345-347, 600/365, 435/4, 435/14, 422/50, 422420-429, 20440301-40315, 702/23, 604 64- 66
• US Class Current: 1/1
• 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 5/14503 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 5/1468 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 5/1486 using enzyme electrodes, e.g. with immobilised oxidase
• 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 5/7257 using Fourier transforms
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• CPC Class Codes: A61B 5/7264 Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00
• CPC Class Codes: A61B 5/7275 Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: A61B 5/7455 characterised by tactile indication, e.g. vibration or electrical stimulation
• 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: A61B 5/7475 User input or interface means, e.g. keyboard, pointing device, joystick
• CPC Class Codes: A61M 5/1723 using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00
• CPC Class Codes: G16Z 99/00 Subject matter not provided for in other main groups of this subclass
• 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 dynamically and intelligently estimating analyte data from a continuous analyte sensor, including receiving a data stream, selecting one of a plurality of algorithms, and employing the selected algorithm to estimate analyte values. Additional data processing includes evaluating the selected estimative algorithms, analyzing a variation of the estimated analyte values based on statistical, clinical, or physiological parameters, comparing the estimated analyte values with corresponding measure analyte values, and providing output to a user. Estimation can be used to compensate for time lag, match sensor data with corresponding reference data, warn of upcoming clinical risk, replace erroneous sensor data signals, and provide more timely analyte information encourage proactive behavior and preempt clinical risk.

Claims

1. A method for processing glucose sensor data, the method comprising:

obtaining a glucose measurement using a glucose sensor in contact with a biological fluid, wherein the glucose sensor comprises a first electrode, a second electrode, and an enzyme-containing film, the obtaining comprising;

applying a potential to the glucose sensor at a first setting,

measuring a first signal from the glucose sensor at the first setting,

switching the potential from the first setting to a second setting, wherein the first setting is different from the second setting,

measuring a second signal from the glucose sensor at the second setting, and

generating a glucose concentration value, using a processor coupled to a memory of a sensor electronics unit, based at least in part on the measured first signal and the measured second signal;

displaying, using a display, a first screen presenting generated glucose concentration data over a first time period;

displaying, using the display, a second screen presenting generated glucose concentration data over a second time period, wherein the second time period is different in length from the first time period;

displaying, using the display, a third screen presenting a single generated real-time glucose concentration value;

receiving an input from a user to toggle between the first screen, the second screen, and the third screen of the display;

receiving an input from the user related to mealtime information, wherein the mealtime information is displayable on the display;

receiving information from the user related to a glucose concentration target range, wherein the glucose concentration target range is represented by an upper boundary and a lower boundary, and wherein the upper boundary and the lower boundary are user configurable; and

generating an alert responsive to detection of a hyperglycemic condition or a hypoglycemic condition based at least in part on the single generated real-time glucose concentration value being outside the glucose concentration target range,

wherein the sensor electronics unit is configured to modify a glucose concentration determined from the first signal by accounting for an adjustment derived from the second signal.

2. The method of claim 1, further comprising:

selecting an algorithm based at least in part on a physiological parameter, where the glucose concentration value is generated based on the selected algorithm.

3. The method of claim 1, wherein the biological fluid is interstitial fluid.

4. The method of claim 1, wherein the biological fluid is blood.

5. The method of claim 1, further comprising:

determining a measurement of blood cells.

6. The method of claim 1, displaying, using the display, a numerical representation of date and time.

7. The method of claim 1, wherein the generating the alert includes transmitting the alert through an audible and visual alarm.

8. The method of claim 1, further comprising:

detecting a temperature measurement using a temperature sensor operatively connected to the processor.

9. The method of claim 1, wherein the first screen and the second screen each present a trend graph, where the first screen comprises a first trend graph and the second screen comprises a second trend graph, where the first trend graph and the second trend graph each comprise a most recent result, wherein the most recent result of the first trend graph is presented on a right side of the first screen, wherein the most recent result of the second trend graph is presented on a right side of the second screen.

10. The method of claim 1, wherein the enzyme-containing film has a thickness between 50 microns and 135 microns.

11. The method of claim 1, wherein the first signal is associated with glucose concentration, the method comprising processing the second signal to reduce or eliminate an effect that interferes with measurement of glucose concentration.

12. A glucose sensor system, the system comprising:

a glucose sensor configured to be in contact with a biological fluid to obtain a glucose measurement, wherein the glucose sensor comprises a first electrode, a second electrode, and an enzyme-containing film;

sensor electronics comprising a processor for executing computer program code stored in memory to cause the processor to;

apply a potential to the glucose sensor at a first setting,

measure a first signal from the glucose sensor at the first setting,

switch the potential from the first setting to a second setting, wherein the first setting is different from the second setting,

measure a second signal from the glucose sensor at the second setting, and

generate a glucose concentration value based at least in part on the first signal and the second signal; and

a user interface configured to;

display a first screen presenting generated glucose concentration data over a first time period,

display a second screen presenting generated glucose concentration data over a second time period, wherein the second time period is different in length from the first time period,

display a third screen presenting a single generated real-time glucose concentration value,

allow a user to toggle between the first screen, the second screen, and the third screen,

receive an input from the user related to mealtime information and display mealtime information on the user interface,

receive information from the user related to a glucose concentration target range, wherein the glucose concentration target range is represented by an upper boundary and a lower boundary, wherein the upper boundary and the lower boundary are user configurable, and

generate an alert responsive to detection of a hyperglycemic condition or a hypoglycemic condition,

wherein the sensor electronics unit is configured to modify a glucose concentration determined from the first signal by accounting for an adjustment derived from the second signal.

13. The system of claim 12, wherein the memory of the sensor electronics further includes computer code to cause the processor to select an algorithm based at least in part on a physiological parameter, where the glucose concentration value is generated based on the selected algorithm.

14. The system of claim 12, wherein the biological fluid is interstitial fluid.

15. The system of claim 12, wherein the biological fluid is blood.

16. The system of claim 12, wherein the glucose sensor system is further configured to determine a measurement of blood cells.

17. The system of claim 12, wherein the glucose sensor system is configured to display a deviation.

18. The system of claim 12, wherein the user interface is configured to display a numerical representation of date and time.

19. The system of claim 12, wherein the user interface is configured to alert the user through an audible and visual alarm.

20. The system of claim 12, wherein the glucose sensor system further comprises a temperature sensor operatively connected to the processor of the electronics unit.

21. The system of claim 12, wherein the sensor electronics and the display configured to display the user interface are housed in a hand-held device.

22. The system of claim 12, wherein the first screen and the second screen each present a trend graph, where the first screen comprises a first trend graph and the second screen comprises a second trend graph, where the first trend graph and the second trend graph each comprise a most recent result, wherein the most recent result of the first trend graph is presented on a right side of the first screen, wherein the most recent result of the second trend graph is presented on a right side of the second screen.

23. The system of claim 12, wherein the enzyme-containing film has a thickness between 50 microns and 135 microns.

24. The system of claim 12, wherein the first signal is associated with glucose concentration, and the sensor electronics unit is configured to process the second signal to reduce or eliminate an effect that interferes with measurement of glucose concentration.

25. A method for processing glucose sensor data, the method comprising:

obtaining a glucose measurement using a glucose sensor in contact with a biological fluid, wherein the glucose sensor comprises a first electrode, a second electrode, and an enzyme-containing film, the obtaining comprising;

applying a potential to the glucose sensor at a first setting,

measuring a first signal from the glucose sensor at the first setting, wherein the first signal is associated with glucose concentration,

switching the potential from the first setting to a second setting, wherein the first setting is different from the second setting,

measuring a second signal from the glucose sensor at the second setting, and

generating a glucose concentration value, using a processor coupled to a memory of a sensor electronics unit, based at least in part on the measured first signal and the measured second signal;

displaying, using the display, a first screen presenting generated glucose concentration data over a first time period;

displaying, using the display, a second screen presenting generated glucose concentration data over a second time period, wherein the second time period is different in length from the first time period;

displaying, using the display, a third screen presenting a single generated real-time glucose concentration value;

receiving an input from a user to toggle between the first screen, the second screen, and the third screen of the display;

receiving an input from the user related to mealtime information, wherein the mealtime information is displayable on the display;

receiving information from the user related to a glucose concentration target range, wherein the glucose concentration target range is represented by an upper boundary and a lower boundary, and wherein the upper boundary and the lower boundary are user configurable; and

generating an alert responsive to detection of a hyperglycemic condition or a hypoglycemic condition based at least in part on the single generated real-time glucose concentration value being outside the glucose concentration target range,

wherein the sensor electronics unit is configured to process the second signal to reduce or eliminate an effect that interferes with measurement of glucose concentration.

26. The method of claim 25, further comprising:

selecting an algorithm based at least in part on a physiological parameter, where the glucose concentration value is generated based on the selected algorithm.

27. The method of claim 25, wherein the biological fluid is interstitial fluid.

28. The method of claim 25, wherein the biological fluid is blood.

29. The method of claim 25, further comprising:

determining a measurement of blood cells.

30. The method of claim 25, displaying, using the display, a numerical representation of date and time.

31. The method of claim 25, wherein the generating the alert includes transmitting the alert through an audible and visual alarm.

32. The method of claim 25, further comprising:

detecting a temperature measurement using a temperature sensor operatively connected to the processor.

33. The method of claim 25, wherein the first screen and the second screen each present a trend graph, where the first screen comprises a first trend graph and the second screen comprises a second trend graph, where the first trend graph and the second trend graph each comprise a most recent result, wherein the most recent result of the first trend graph is presented on a right side of the first screen, wherein the most recent result of the second trend graph is presented on a right side of the second screen.

34. The method of claim 25, wherein the enzyme-containing film has a thickness between 50 microns and 135 microns.

35. A glucose sensor system, the system comprising:

a glucose sensor configured to be in contact with a biological fluid to obtain a glucose measurement, wherein the glucose sensor comprises a first electrode, a second electrode, and an enzyme-containing film;

sensor electronics comprising a processor for executing computer program code stored in memory to cause the processor to;

apply a potential to the glucose sensor at a first setting,

measure a first signal from the glucose sensor at the first setting, wherein the first signal is associated with glucose concentration,

switch the potential from the first setting to a second setting, wherein the first setting is different from the second setting,

measure a second signal from the glucose sensor at the second setting, and

generate a glucose concentration value based at least in part on the first signal and the second signal; and

a user interface configured to;

display a first screen presenting generated glucose concentration data over a first time period,

display a second screen presenting generated glucose concentration data over a second time period, wherein the second time period is different in length from the first time period,

display a third screen presenting a single generated real-time glucose concentration value,

allow a user to toggle between the first screen, the second screen, and the third screen,

receive an input from the user related to mealtime information and display mealtime information on the user interface,

receive information from the user related to a glucose concentration target range, wherein the glucose concentration target range is represented by an upper boundary and a lower boundary, wherein the upper boundary and the lower boundary are user configurable, and

generate an alert responsive to detection of a hyperglycemic condition or a hypoglycemic condition,

wherein the sensor electronics unit is configured to process the second signal to reduce or eliminate an effect that interferes with measurement of glucose concentration.

36. A method for processing glucose sensor data, the method comprising:

obtaining a glucose measurement using a glucose sensor in contact with a biological fluid, wherein the glucose sensor comprises a first electrode, a second electrode, and an enzyme-containing film, the obtaining comprising;

applying a potential to the glucose sensor at a first setting,

measuring a first signal from the glucose sensor at the first setting,

switching the potential from the first setting to a second setting, wherein the first setting is different from the second setting,

measuring a second signal from the glucose sensor at the second setting, and

generating a glucose concentration value, using a processor coupled to a memory of a sensor electronics unit, based at least in part on the measured first signal and the measured second signal;

producing a user interface displayable using a display including a first screen of the user interface presenting generated glucose concentration data over a first time period, a second screen of the user interface presenting generated glucose concentration data over a second time period, where the second time period is different in length from the first time period, and a third screen of the user interface presenting a single generated real-time glucose concentration value;

toggling between the first screen, the second screen, and the third screen of the user interface when a toggle input is received;

receiving information from a user related to a glucose concentration target range, wherein the glucose concentration target range is represented by an upper boundary and a lower boundary, and wherein the upper boundary and the lower boundary are user configurable; and

generating an alert responsive to detection of a hyperglycemic condition or a hypoglycemic condition based at least in part on the single generated real-time glucose concentration value being outside the glucose concentration target range,

wherein the sensor electronics unit is configured to modify a glucose concentration determined from the first signal by accounting for an adjustment derived from the second signal.