Systems and methods for replacing signal artifacts in a glucose sensor data stream

• US 9,420,968 B2
• Filed: 04/04/2012
• Issued: 08/23/2016
• Est. Priority Date: 08/22/2003
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Kamath, Apurv, Brauker, James H., Mahalingam, Aarthi, Li, Ying
• Primary Examiner(s): JANG, CHRISTIAN YONGKYUN
• Application Number:
  US13/439,671
• Publication Number:
  US 20120245855A1
• Time in Patent Office: 1,602 Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2560/0252 using ambient temperature
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• 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 5/14532 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 5/14865 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors
• CPC Class Codes: A61B 5/6848 Needles
• 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 5/7239 using differentiation including higher order derivatives
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: A61B 5/726 using Wavelet transforms
• CPC Class Codes: A61B 5/742 using visual displays A61B5/339 takes precedence
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems
• 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 minimizing or eliminating transient non-glucose related signal noise due to non-glucose rate limiting phenomenon such as interfering species, ischemia, pH changes, temperatures changes, known or unknown sources of mechanical, electrical and/or biochemical noise, 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 processes some or the entire data stream continually or intermittently based at least in part on whether the signal artifact event has occurred.

Claims

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

receiving sensor data from a glucose sensor for a time period;

evaluating, using one or more processors, the sensor data to detect signal artifacts, the evaluating comprising performing a first derivative analysis of the sensor data and performing a second derivative analysis of the sensor data;

determining, using the one or more processors, a level of confidence based on the evaluation;

generating insulin administration instructions based on the sensor data;

outputting an indication of the level of confidence; and

administering, using the insulin administration device, insulin to a host based on the insulin administration instructions.

2. The method of claim 1, further comprising filtering the sensor data responsive to the evaluation.

3. The method of claim 1, further comprising selectively displaying, on a display device, one or more representations of the sensor data based on the evaluation.

4. The system of claim 1, further comprising selectively displaying, on a display device, one or more of a representation of raw continuous glucose sensor data, a representation of filtered continuous glucose sensor data, a representation of a range of data values associated with the continuous glucose sensor data, a representation of a direction of the continuous glucose sensor data, a representation of a level of confidence of the continuous glucose sensor data, a low resolution representation of the continuous glucose sensor data or a representation of predicted continuous glucose sensor data for a future time period based on the evaluation.

5. The method of claim 1, further comprising estimating glucose concentration values based on the sensor data, wherein the estimation is temporarily disabled responsive to the evaluation meeting a criterion.

6. The method of claim 5, wherein the estimation comprises predicting the glucose concentration values for a future time.

7. The method of claim 1, wherein the evaluation comprises comparing the first derivative analysis to the second derivative analysis.

8. The method of claim 1, further comprising:

receiving, at an insulin administration device, the insulin administration instructions.

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

a sensor data receiving module configured to receive sensor data from a glucose sensor for a time period;

signal artifacts detection module configured to evaluate the sensor data to detect signal artifacts, the evaluating comprising performing a first derivative analysis of the sensor data and performing a second derivative analysis of the sensor data, wherein the signal artifacts detection module determines a level of confidence based on the evaluation;

a processor module configured to generate insulin administration instructions based on the sensor data;

an output module configured to provide an indication of the level of confidence; and

a medicament delivery device configured to administer insulin to a host based on the insulin administration instructions.

10. The system of claim 9, wherein the processor module is further configured to filter the sensor data responsive to the evaluation.

11. The system of claim 9, wherein the processor module is further configured to selectively display one or more representations of the sensor data based on the evaluation.

12. The system of claim 9, wherein the processor module is further configured to selectively display one or more of a representation of raw continuous glucose sensor data, a representation of filtered continuous glucose sensor data, a representation of a range of data values associated with the continuous glucose sensor data, a representation of a direction of the continuous glucose sensor data, a representation of a level of confidence of the continuous glucose sensor data, a low resolution representation of the continuous glucose sensor data or a representation of predicted continuous glucose sensor data for a future time period based on the evaluation.

13. The system of claim 9, wherein the processor module is further configured to estimate glucose concentration values based on the sensor data, wherein the processor module estimation temporarily disables the estimation responsive to the evaluation meeting a criterion.

14. The system of claim 13, wherein the estimation comprises prediction.

15. The system of claim 9, wherein the evaluation comprises comparing the first derivative analysis to the second derivative analysis.