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

• US 20100036224A1
• Filed: 10/14/2009
• Published: 02/11/2010
• Est. Priority Date: 08/22/2003
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: Deccom Incorporated
• Inventors: Brauker, James H., Carr-Brendel, Victoria, Thrower, James Patrick, Kamath, Apurv U., Goode, Paul V. JR.
• Granted Patent: US 8,073,519 B2
• Time in Patent Office: Days
• US Class Current: 600/365
• 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. In a glucose sensing system comprising a glucose sensor configured for producing an output representative of glucose concentration in a host and processing circuitry configured to process the output, a method for processing data from the output, the method comprising:

generating at least one data stream from the glucose sensor output;

evaluating the data stream to determine a presence of a signal artifact;

generating an estimated data stream;

replacing a portion of the data stream with the estimated data stream; and

terminating replacement of the data stream with the estimated data stream based at least in part on either detection of a reduction of the signal artifact or passing of a predetermined time period.

2. The method of claim 1, comprising determining a severity of the signal artifact.

3. The method of claim 2, comprising terminating signal estimation based at least in part on the severity of the signal artifact.

4. The method of claim 2, wherein the severity of the signal artifact is determined at least in part by determining the duration of the signal artifact.

5. The method of claim 2, wherein the severity of the signal artifact is determined at least in part by determining an amplitude of the signal artifact.

6. The method of claim 1, wherein generating the estimated data stream is performed in response to the detection of the presence of the signal artifact.

7. A glucose sensor system for monitoring a glucose concentration in a host, the system comprising:

a continuous glucose sensor configured to produce a data stream;

a signal artifact detection module configured to detect a presence of a signal artifact in the data stream;

a signal estimation module configured to perform signal estimation to generate an estimated data stream; and

a signal artifact replacement module configured to;

replace a portion of the data stream with the estimated data stream in response to a positive detection of the presence of the signal artifact; and

terminate replacement of the data stream with the estimated data stream based at least in part on either detection of a reduction of the signal artifact or passing of a predetermined time period.

8. The system of claim 7, wherein the system is configured to determine a severity of the signal artifact.

9. The system of claim 8, wherein the system is configured to terminate data stream replacement based at least in part on the severity of the signal artifact.

10. The system of claim 8, wherein the system is configured to determine the severity of the signal artifact based at least in part on the duration of the signal artifact.

11. The system of claim 8, wherein the system is configured to determine the severity of the signal artifact based at least in part on an amplitude of the signal artifact.

12. The system of claim 7, wherein the system is configured to perform signal estimation is performed in response to the detection of the presence of the signal artifact.

13. The system of claim 7, wherein the signal artifact detection module is housed in at least one of a sensor electronics housing or a receiver electronics housing.