SIGNAL PROCESSING FOR CONTINUOUS ANALYTE SENSOR

• US 20100045465A1
• Filed: 10/12/2009
• Published: 02/25/2010
• Est. Priority Date: 12/09/2003
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Brauker, James H., Carr-Brendel, Victoria, Goode, Paul V., Kamath, Apurv U., Thrower, James P., Xavier, Ben
• Granted Patent: US 9,351,668 B2
• Time in Patent Office: Days
• US Class Current: 340/573.100
• 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 glucose sensor system for monitoring glucose concentration in a biological sample of a host, the system comprising:

a continuous glucose sensor configured to produce sensor data indicative of a host'"'"'s glucose concentration, wherein the continuous glucose sensor comprises a sensing region and a sensing membrane located over the sensing region, and wherein at least a portion of the glucose sensor is configured for transcutaneous implantation; and

an electronics module configured to receive sensor data from the continuous glucose sensor, the electronics module comprising a processor configured to process sensor data received from the continuous glucose sensor for a first time period, to calibrate sensor data using a glucose concentration measured by a reference glucose monitor operatively linked to the electronics module so as to generate real-time glucose readings from the sensor data and the calibration;

wherein the electronics module is further configured to detect an approaching clinical risk and to activate an alarm based at least in part on the detection, and wherein the detection comprises predicting potential glucose concentration for a second time period based at least in part on both an extrapolation of real time glucose readings and on a variation analysis.

2. The system of claim 1, wherein the processor is configured to activate an alarm when a predicted potential glucose concentration value is greater than a high threshold value or less than a low threshold value.

3. The system of claim 1, wherein the alarm comprises an audible signal.

4. The system of claim 1, wherein the alarm comprises a tactile signal.

5. The system of claim 1, wherein the high threshold value and the low threshold value are user configurable.

6. The system of claim 1, wherein the reference glucose monitor is integral with the electronics module.

7. The system of claim 1, wherein the variation analysis comprises a statistical analysis.

8. The system of claim 1, wherein the variation analysis comprises a clinical analysis.

9. The system of claim 1, wherein the variation analysis comprises a physiological analysis.

10. A device for processing continuous glucose sensor data, the device comprising:

a housing;

a receiver configured for receiving sensor data from a continuous glucose sensor;

a processor; and

a computer readable memory comprising;

instructions configured to cause the processor to process sensor data received from the continuous glucose sensor for a first time period;

instructions configured to cause the processor to calibrate the processed sensor data using a glucose concentration measured by a reference glucose monitor operatively linked to the device so as to generate real-time glucose readings from the sensor data and the calibration for a first time period;

instructions configured to cause the processor to detect an approaching clinical risk by predicting a potential glucose concentration value for a second time period based at least in part on both an extrapolation of calibrated sensor data and on a variation analysis; and

instructions configured to cause the processor to activate an alarm based at least in part on the detection.

11. The device of claim 10, wherein the alarm is activated when the predicted potential glucose concentration is greater than a high threshold value or less than a low threshold value.

12. The device of claim 10, wherein the alarm comprises an audible signal.

13. The device of claim 10, wherein the alarm comprises a tactile signal.

14. The device of claim 10, wherein the high threshold value and the low threshold value are user configurable.

15. The device of claim 10, wherein the reference glucose monitor is integrally formed with the housing and is configured to measure a glucose concentration in a biological sample.

16. The device of claim 10, wherein the variation analysis comprises a statistical analysis.

17. The device of claim 10, wherein the variation analysis comprises a clinical analysis.

18. The device of claim 10, wherein the variation analysis comprises a physiological analysis.

19. A method for processing sensor data, the method comprising:

receiving, with an electronic device, sensor data from a continuous glucose sensor;

measuring at least one glucose concentration of a biological sample using a reference glucose monitor operatively linked to an electronics module;

calibrating sensor data by using at least one glucose concentration measurement by the reference glucose monitor;

detecting an approaching clinical risk by performing both an extrapolation of previously calibrated sensor data and performing a variation analysis; and

activating an alarm based at least in part on the detecting.

20. The method of claim 19, wherein the alarm comprises an audible signal.

21. The method of claim 19, wherein the alarm comprises a tactile signal.

22. The method of claim 19, wherein the high threshold value and the low threshold value are user configurable.

23. The method of claim 19, wherein the reference glucose monitor is integral with the electronics module.

24. The method of claim 19, wherein the variation analysis comprises a statistical analysis.

25. The method of claim 19, wherein the variation analysis comprises a clinical analysis.

26. The method of claim 19, wherein the variation analysis comprises a physiological analysis.

27. A system for processing sensor data from a continuous glucose sensor, the system comprising:

means for receiving sensor data from the continuous glucose sensor;

means for measuring at least one glucose concentration of a biological sample using a reference glucose monitor operatively linked to an electronics module;

means for calibrating sensor data by using at least one glucose concentration measurement by the reference glucose monitor;

means for detecting an approaching clinical risk by performing both an extrapolation of previously calibrated sensor data and performing a variation analysis; and

means for activating an alarm based at least in part on the detecting.