Analyte sensor

• US 8,425,416 B2
• Filed: 03/25/2008
• Issued: 04/23/2013
• Est. Priority Date: 10/04/2006
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Brister, Mark, Simpson, Peter C., Kamath, Apurv Ullas, Leach, Jacob S., Swanson, Vance, Saint, Sean, Nolting, John
• Primary Examiner(s): Marmor, II, Charles A
• Assistant Examiner(s): TOTH, KAREN E
• Application Number:
  US12/055,203
• Publication Number:
  US 20080200789A1
• Time in Patent Office: 1,855 Days
• Field of Search: 600/347, 600/365
• US Class Current: 600/309
• 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 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• 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 5/412 Detecting or monitoring sepsis
• CPC Class Codes: A61B 5/6848 Needles
• CPC Class Codes: A61B 5/6849 in combination with a needle set
• CPC Class Codes: A61M 2230/201 Glucose concentration
• CPC Class Codes: A61M 25/00 Catheters; Hollow probes dilators A61M29/00; peritoneal catheters A61M1/285; tracheal tubes A61M16/04; for drainage A61M27/00; for uterus, vagina or rectum A61M31/00 ; for measuring or testing A61B; materials for catheters A61L29/00
• CPC Class Codes: A61M 5/14 Infusion devices, e.g. infusing by gravity; Blood infusion; Accessories therefor
• CPC Class Codes: A61M 5/16804 Flow controllers
• CPC Class Codes: C12Q 1/001 Enzyme electrodes
• CPC Class Codes: C12Q 1/006 for glucose
• CPC Class Codes: G16H 20/17 delivered via infusion or injection
• CPC Class Codes: G16H 40/40 for the management of medical equipment or devices, e.g. scheduling maintenance or upgrades
• 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 of use for continuous analyte measurement of a host'"'"'s vascular system are provided. In some embodiments, a continuous glucose measurement system includes a vascular access device, a sensor and sensor electronics, the system being configured for insertion into communication with a host'"'"'s circulatory system.

Claims

1. A system for continuous measurement of a glucose concentration, the system comprising:

a continuous glucose sensor comprising a first working electrode and a second working electrode, wherein the continuous glucose sensor is located at least in part in a fluid coupler configured to be in fluid communication with a vascular access device configured to be in fluid communication with a host'"'"'s circulatory system;

a flow control device configured to intermittently meter a glucose reference solution across the continuous glucose sensor such that the continuous glucose sensor intermittently measures the glucose concentration of the reference solution, and wherein the system is configured to calibrate the continuous glucose sensor using the measured glucose concentration of the reference solution; and

a processor module operatively connected to the continuous glucose sensor and the fluid control device, wherein the processor module is configured to use a priori information to set tolerances for at least one of sensitivity drift or baseline drift.

2. The system of claim 1, wherein the processor module is configured to process signals from the first working electrode and second working electrode to obtain a substantially baseline-free glucose signal.

3. The system of claim 2, wherein the processor module is configured to calibrate the continuous glucose sensor using an equation that does not include a baseline parameter.

4. The system of claim 1, wherein the processor module is configured to use the measured glucose concentration of the reference solution to determine a sensitivity of the continuous glucose sensor.

5. The system of claim 4, wherein the processor module is configured to calibrate the continuous glucose sensor using the sensitivity of the continuous glucose sensor.

6. A system for continuous measurement of an analyte concentration, the system comprising:

a continuous analyte sensor located in at least one of a vascular access device or a fluid coupler configured to be in fluid communication with a host'"'"'s circulatory system;

a flow control device configured to intermittently withdraw a blood sample from the host'"'"'s circulatory system to the continuous analyte sensor; and

a processor module operatively connected to the continuous analyte sensor and the flow control device, wherein the processor module is configured to use a priori information to establish at least one predetermined boundary set for a conversion function drawn from calibration.

7. The system of claim 6, wherein the flow control device is configured to intermittently meter a reference solution across the continuous analyte sensor such that the continuous analyte sensor is in continuous contact with either the reference solution or a blood sample from the host'"'"'s circulatory system, and wherein the flow control device is configured to meter the reference solution such that the sensor is contacting the reference solution at least about 50% of the time during a sensor session.

8. The system of claim 7, wherein the flow control device is configured to meter the reference solution such that the sensor is contacting the reference solution at least about 80% of the time during a sensor session.

9. The system of claim 7, wherein the flow control device is configured to meter the reference solution such that the sensor is contacting the reference solution a sufficient amount of time such that biofouling does not occur for at least about 3 days of sensor use.

10. The system of claim 9, wherein the flow control device is configured to meter reference solution such that the sensor is contacting the reference solution a sufficient amount of time such that biofouling does not occur for at least about 7 days of sensor use.

11. The system of claim 10, wherein the flow control device is configured to meter reference solution such that the sensor is contacting the reference solution a sufficient amount of time such that biofouling does not occur for at least about 21 days of sensor use.

12. The system of claim 11, wherein the flow control device is configured to meter reference solution such that the sensor is contacting the reference solution a sufficient amount of time such that biofouling does not occur for at least about 30 days of sensor use.

13. The system of claim 9, wherein the sufficient amount of time is at least about 50% of the time during sensor use.

14. The system of claim 9, wherein the sufficient amount of time is at least about 65% of the time during sensor use.

15. The system of claim 9, wherein the sufficient amount of time is at least about 80% of the time during sensor use.

16. The system of claim 7, wherein the flow control device is configured to meter the reference solution through the vascular access device for a sufficient amount of time with a sufficient flow rate such that the vascular access device remains patent during a sensor session of at least about 3 days.

17. The system of claim 16, wherein the flow control device is configured to meter the reference solution through the vascular access device for at least about 50% of a sensor session, at a flow rate from about 0.001 ml/min to about 2 ml/min.

18. The system of claim 16, wherein the flow control device is configured to meter the reference solution through the vascular access device for at least about 65% of a sensor session, at a flow rate from about 0.5 ml/min to about 2 ml/min, whereby the vascular access device remains patent during a sensor session of from about 3 days to about 30 days.