Method and system for providing continuous calibration of implantable analyte sensors

• US 20090054748A1
• Filed: 02/28/2006
• Published: 02/26/2009
• Est. Priority Date: 02/28/2006
• Status: Active Grant

• Current Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories Incorporated)
• Original Assignee: Abbott Diabetes Care Incorporated (Abbott Laboratories Incorporated)
• Inventors: Feldman, Benjamin J.
• Granted Patent: US 7,885,698 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 5/0017 transmitting optical signals transmission by light H04B10/00
• CPC Class Codes: A61B 5/0024 for multiple sensor units attached to the patient, e.g. using a body or personal area network
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/14503 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors A61B5/1459, A61B5/1464, A61B5/1473, A61B5/1482, A61B5/14865 take precedence
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: A61B 5/6846 specially adapted to be brought in contact with an internal body part, i.e. invasive
• CPC Class Codes: A61B 5/7246 using correlation, e.g. template matching or determination of similarity
• CPC Class Codes: A61M 5/1723 using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems
• CPC Class Codes: H04L 67/12 specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks

Abstract

Method and system for providing continuous calibration of analyte sensors includes calibrating a first sensor, receiving data associated with detected analyte levels from the first sensor, and calibrating a second sensor based on a predetermined scaling factor and data associated with detected analyte levels from the first sensor, is disclosed.

Claims

1. A method of providing continuous calibration of analyte sensors, comprising:

calibrating a first sensor;

receiving data associated with detected analyte levels from the first sensor; and

calibrating a second sensor with reference to one or more detected analyte levels from the first sensor.

2. The method of claim 1 further including the step of calibrating a third sensor based on a second scaling factor and data associated with detected analyte levels from the second sensor.

3. The method of claim 1 wherein the step of calibrating the second sensor starts after a predetermined time period has passed where the first sensor has been in fluid contact with an analyte of a patient.

4. The method of claim 3 wherein the predetermined time period includes at least approximately 90% of the life of the first sensor.

5. The method of claim 3 wherein the predetermined time period includes at least approximately 50% of the life of the first sensor.

6. The method of claim 1 further including the step of determining a sensitivity of the first sensor.

7. The method of claim 1 further including the step of receiving data associated with detected analyte levels from the second sensor.

8. The method of claim 1 wherein the step of calibrating the second sensor includes the steps of:

determining an analyte level; and

comparing the determined analyte level with the data associated with the detected analyte level from the first sensor.

9. The method of claim 1 wherein the step of calibrating the second sensor includes the steps of:

determining a scaling factor based on substantially simultaneous data from the first sensor and the second sensor;

applying the scaling factor to the data from the second sensor; and

determining a correlation level of data from the first sensor and from the second sensor.

10. The method of claim 9 wherein the step of determining the scaling factor includes the steps of

comparing the substantially simultaneous data from the first sensor with the data from the second sensor;

and

determining the scaling factor based on a calculated scaling factor with the lowest level of average error between the data of the first sensor and the data of the second sensor.

11. The method of claim 9 further including the step of comparing the correlation level with a predetermined correlation threshold defining an acceptable stability level of the second sensor.

12. The method of claim 1 wherein the first sensor and the second sensor are analyte sensors.

13. The method of claim 1 further including the step of removing the first sensor while retaining the second sensor in fluid contact with the analyte of a patient.

14. The method of claim 1 wherein the first sensor and the second sensor are subcutaneously positioned under a skin of a patient.

15. The method of claim 14 wherein at least a portion of the first sensor and at least a portion of the second sensor are in fluid contact with the patient'"'"'s analyte.

16. A system for providing continuous analyte sensor calibration comprising:

a first sensor for subcutaneous placement in a patient; and

a second sensor for subcutaneous placement in the patient after calibration of the first sensor;

wherein at least a portion of the first sensor and at least a portion of the second sensor are in fluid contact with the patient'"'"'s analyte substantially simultaneously for a time period.

17. The system of claim 16 wherein the second sensor is subcutaneously placed in the patient after a predetermined time period has passed where the first sensor has been in fluid contact with an analyte of a patient.

18. The system of claim 17 wherein the predetermined time period includes at least approximately 90% of the life of the first sensor.

19. The system of claim 17 wherein the predetermined time period includes at least approximately 50% of the life of the first sensor.

20. The system of claim 16 wherein the time period is predetermined and includes approximately 2 hours to 10 hours.

21. The system of claim 16 wherein the time period is variable, and wherein the variable time period is determined to be when the analyte levels measured by the first and second sensors are within a correlation range.

23. The system of claim 16 wherein the first sensor is operatively coupled to a first transmitter unit, and the second sensor is operatively coupled to a second transmitter unit, the first and second transmitter units configured to receive data from the corresponding first and second sensors, respectively, for transmission over a communication link.

24. The system of claim 16 wherein the first transmitter unit and the second transmitter unit are coupled to a single transmitter housing.

25. The system of claim 16 wherein the communication link includes one or more of an RF communication link, a Bluetooth communication link, an infrared communication link, or a cable communication link.

26. The system of claim 16 further including a receiver unit configured to substantially simultaneously receive data from the first transmitter unit and the second transmitter unit.

28. The system of claim 26 wherein the receiver unit further includes an infusion device.

29. The system of claim 26 wherein the receiver unit is configured to calibrate the second sensor based on analyte levels measured by the first sensor.

30. The system of claim 26 wherein the receiver unit is configured to receive data from one or more of the first sensor or the second sensor at predetermined time intervals such that there is no interruption in the received data after the first sensor is removed from the patient.

37. The system of claim 16 wherein the time period is variable, and wherein the variable time period is determined to be when the analyte levels measured by the first and second sensors are within a correlation range.

22. The system of 21, wherein the correlation range is determined by a preset threshold value.

27. The system of 26 wherein the receiver unit includes first receiver section operatively coupled to the first transmitter unit, and a second receiver section operatively coupled to the second transmitter unit, the second receiver section further operatively coupled to the first receiver section for data communication.

31. A method, comprising:

positioning a first sensor in fluid contact with an analyte of a patient;

calibrating the first sensor;

positioning a second sensor in fluid contact with the analyte of the patient after calibrating the first sensor;

calibrating the second sensor based on data from the first sensor; and

removing the first sensor while retaining the second sensor in fluid contact.

32. The method of claim 31 wherein the second sensor is subcutaneously placed in the patient after a predetermined time period has passed where the first sensor has been in fluid contact with an analyte of a patient.

33. The system of claim 32 wherein the predetermined time period includes at least approximately 90% of the life of the first sensor.

34. The system of claim 32 wherein the predetermined time period includes at least approximately 50% of the life of the first sensor.

35. A system for determining the stability of an analyte sensor calibration, comprising:

a first sensor for subcutaneous placement in a patient; and

a second sensor for subcutaneous placement in the patient after calibration of the first sensor;

wherein at least a portion of the first sensor and at least a portion of the second sensor are in fluid contact with the patient'"'"'s analyte substantially simultaneously for a time period; and

further

wherein the stability of the second sensor is determined with reference to data from the first sensor.

36. The system of claim 35 wherein the time period is predetermined and includes approximately 2 hours to 10 hours.

38. The system of 37, wherein the correlation range is determined by a preset threshold value.

39. A system for determining analyte concentrations, consisting essentially of:

a plurality of analyte sensors;

a plurality of transmitter units, each of the plurality of transmitter units operatively coupled to a respective one of the plurality of analyte sensors; and

a receiver unit configured to receive and process data substantially simultaneously from each of the plurality of transmitter units.

40. The system of claim 39, where each transmitter is uniquely couple to a single analyte sensor.

41. The system of claim 39, where the receiver unit comprises a comparison unit for comparing the one or more signals from the plurality of transmitters units, and further, for determining the stability of the plurality of sensors.

42. The system of claim 39 wherein the receiver unit is further configured to determine the calibration of the plurality of sensors based on the comparison unit.