SYSTEMS AND METHODS FOR REPLACING SIGNAL ARTIFACTS IN A GLUCOSE SENSOR DATA STREAM

• US 20170209101A1
• Filed: 04/06/2017
• Published: 07/27/2017
• Est. Priority Date: 08/22/2003
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Kamath, Arpurv U., Brauker, James H., Goode, Paul V., Thrower, James Patrick, Carr-Brendel, Victoria
• Granted Patent: US 9,724,045 B1
• Time in Patent Office: Days
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 2562/0271 Thermal or temperature sensors
• CPC Class Codes: A61B 2562/08 Sensors provided with means for identification, e.g. barcodes or memory chips
• CPC Class Codes: A61B 5/0004 characterised by the type of physiological signal transmitted
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• 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 5/1473 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 5/7203 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 5/7257 using Fourier transforms
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• CPC Class Codes: A61B 5/7278 Artificial waveform generation or derivation, e.g. synthesising signals from measured signals A61B5/327 takes precedence
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: A61B 5/7475 User input or interface means, e.g. keyboard, pointing device, joystick

Abstract

Systems and methods for minimizing or eliminating transient non-glucose related signal noise due to non-glucose rate limiting phenomenon such as ischemia, pH changes, temperatures changes, 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 replaces some or the entire data stream continually or intermittently including signal estimation methods that particularly address transient signal artifacts. The system is also capable of detecting the severity of the signal artifacts and selectively applying one or more signal estimation algorithm factors responsive to the severity of the signal artifacts, which includes selectively applying distinct sets of parameters to a signal estimation algorithm or selectively applying distinct signal estimation algorithms.

Claims

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

monitoring a data stream generated by a working electrode of a continuous glucose sensor, the data stream comprising a glucose sensor data point;

monitoring an output of a counter electrode of the continuous glucose sensor;

detecting a signal artifact associated with the glucose sensor data point;

classifying the signal artifact based on the monitoring of the output of the counter electrode;

selectively applying one or more of a plurality of signal estimation algorithms based on the classification to generate an estimated sensor data point; and

replacing the sensor data point with the estimated sensor data point.

2. The method of claim 1, wherein the data stream comprises a raw data stream.

3. The method of claim 1, wherein the data stream comprises a calibrated data stream of glucose concentration values.

4. The method of claim 1, wherein the signal artifact is a transient non-glucose related signal artifact.

5. The method of claim 1, further comprising displaying or transmitting the estimated data point.

6. The method of claim 1, wherein the detecting comprises identifying a drop in the output of the counter electrode and associating the output drop with the glucose sensor data point.

7. The method of claim 1, wherein electronic circuitry is used to perform one or more of the monitoring of the data stream, the monitoring of the output, the detecting, the classifying, the selectively applying and the replacing.

8. The method of claim 1, wherein the continuous glucose sensor is an implantable sensor comprising the working electrode, the counter electrode and a reference electrode.

9. The method of claim 1, wherein the detecting comprises comparing the data stream with the output of the counter electrode.

10. The method of claim 1, wherein the output of the counter electrode is measured in units of counts.

11. The method of claim 1, wherein the classifying comprises classifying a severity of the signal artifact.

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

a continuous glucose sensor comprising a working electrode configured to generate a data stream and a counter electrode configured to generate a counter electrode output; and

an artifact replacement module configured to;

monitor the counter electrode output;

detect a signal artifact associated with a portion of the data stream;

classify the signal artifact based on the monitoring of the counter electrode output;

selectively apply one or more of a plurality of signal estimation algorithms based on the classification to generate an estimated data stream portion; and

replace the portion of the data stream with the estimated data stream portion.

13. The system of claim 12, wherein the data stream comprises a raw data stream.

14. The system of claim 12, wherein the data stream comprises a calibrated data stream of glucose concentration values.

15. The system of claim 12, wherein the signal artifact is a transient non-glucose related signal artifact.

16. The system of claim 12, further comprising an output module configured to display or transmit the information representative of the estimated data stream portion.

17. The system of claim 12, wherein the artifact replacement module is configured to detect by identifying a drop in the counter electrode output and associating the output drop with the portion of the data stream.

18. The system of claim 12, wherein the continuous glucose sensor is an implantable sensor and further comprises a reference electrode.

19. The system of claim 12, wherein the artifact replacement module is configured to detect by comparing the data stream with the counter electrode output.

20. The system of claim 12, wherein the counter electrode output is measured in units of counts.