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

• US 20100036215A1
• Filed: 10/14/2009
• Published: 02/11/2010
• Est. Priority Date: 08/22/2003
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Brauker, James H., Carr-Brendel, Victoria, Thrower, James Patrick, Kamath, Apurv U., Goode, Paul V. JR.
• Granted Patent: US 8,790,260 B2
• Time in Patent Office: Days
• US Class Current: 600/316
• 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;

filtering the data stream with a filter having an output dependent on previous output values; and

,

generating an estimated data stream, wherein the estimated data stream is based at least in part on the filtered data stream, and is augmented to reduce effects associated with signal loss.

2. The method of claim 1, wherein filtering comprises high pass filtering.

3. The method of claim 1, wherein filtering comprises recursive filtering.

4. The method of claim 1, wherein filtering comprises infinite impulse response filtering.

5. The method of claim 1, wherein the signal loss is caused by transient non-glucose dependent signal loss that has a higher amplitude than system noise.

6. 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; and

,

a signal estimation module configured to receive the data stream comprising a recursive filter and configured to generate an estimated data stream, wherein the estimated data stream is based at least in part on the filtered signal, and is augmented to reduce effects associated with signal loss.

7. The system of claim 6, comprising a high pass filter.

8. The system of claim 7, comprising an infinite impulse response filter.

9. The system of claim 6, wherein the signal estimation module is housed in at least one of a sensor electronics housing or a receiver electronics housing.