Analyte sensor

• US 8,911,367 B2
• Filed: 03/26/2007
• Issued: 12/16/2014
• Est. Priority Date: 10/04/2006
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Brister, Mark, Shults, Mark, Saint, Sean, Petisce, James R., Wong, David K., Woo, Kum Ming
• Primary Examiner(s): Marmor, II, Charles A
• Assistant Examiner(s): TOTH, KAREN E
• Application Number:
  US11/691,424
• Publication Number:
  US 20080086044A1
• Time in Patent Office: 2,822 Days
• Field of Search: None
• US Class Current: 600/309
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• 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 5/1473 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 5/412 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 5/14 Infusion devices, e.g. infusing by gravity; Blood infusion; Accessories therefor
• CPC Class Codes: A61M 5/16804 Flow controllers
• CPC Class Codes: A61M 5/1723 using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00

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 method for measuring a concentration of an analyte in a vein of a host, the method comprising:

providing an analyte measuring system comprising a vascular access device, an analyte sensor configured to measure an analyte concentration and configured to reside within the vascular access device, and electronics operatively connected to the sensor and configured to generate a signal associated with the analyte concentration;

placing the vascular access device and the analyte sensor in fluid communication with a vein of a host;

passing a solution past the analyte sensor and measuring a signal associated with an analyte concentration of the solution; and

drawing back a sample volume of from about 1 μ

l to about 15 μ

l from the vein, measuring a signal associated with the analyte concentration of the sample and subsequently returning the sample back to the vein, wherein the vascular access device comprises a catheter and tubing connected to the catheter.

2. The method of claim 1, wherein passing a solution comprises passing the solution at a first flow rate of from about 0.001 ml/min to about 2 ml/min.

3. The method of claim 2, wherein the first flow rate is from about 0.02 ml/min to about 0.35 ml/min.

4. The method of claim 1, further comprising keeping the vein open by passing the solution past the analyte sensor at a predetermined flow rate.

5. The method of claim 4, wherein the predetermined flow rate is from about 1 μ

l/min to about 1 ml/min.

6. The method of claim 5, wherein the predetermined flow rate is from about 0.02 ml/min to about 0.2 ml/min.

7. The method of claim 1, wherein drawing back the sample from the vein comprises drawing back the sample substantially no farther than the catheter.

8. The method of claim 1, wherein the analyte is glucose, and wherein measuring the concentration of the analyte comprises measuring a glucose concentration.

9. The method of claim 1, further comprising repeating passing and drawing.

10. The method of claim 9, wherein repeating is performed at least one of periodically or intermittently.

11. The method of claim 1, further comprising calibrating the analyte sensor using a baseline measurement obtained from the signal associated with the analyte concentration of the solution.

12. The method of claim 1, further comprising calibrating the analyte sensor using a sensitivity measurement obtained from the signal associated with the analyte concentration of the solution.

13. The method of claim 1, wherein drawing back a sample comprises drawing back a sample at a flow rate of from about 0.001 ml/min to about 2 ml/min.

14. The method of claim 1, wherein placing the vascular access device in fluid communication with a vein comprises placing the vascular access device in a central vein.

15. The method of claim 1, wherein drawing back a sample volume comprises drawing back the sample volume into the catheter, but not into the tubing.

16. A method for measuring a concentration of an analyte in a circulatory system of a host, the method comprising:

providing an analyte measuring system comprising a vascular access device, an analyte sensor configured to measure an analyte concentration, and electronics operatively connected to the analyte sensor and configured to generate a signal associated with the analyte concentration, wherein the analyte sensor is configured to reside within the vascular access device, and wherein the vascular access device and the analyte sensor are configured for fluid communication with the circulatory system;

passing a solution past the analyte sensor and measuring a signal associated with an analyte concentration of the solution; and

drawing back a sample of from about 1 μ

l to about 15 μ

l from the circulatory system and measuring a signal associated with an analyte concentration of the sample, wherein the analyte measuring system further comprises a flow control device, wherein the flow control device is configured to iteratively control four or more different predetermined flow rates.

17. The method of claim 16, wherein the flow control device comprises a valve.

18. The method of claim 16, wherein the flow control device comprises a pump.

19. The method of claim 16, wherein the four or more different predetermined flow rates comprise a draw flow rate associated with drawing back a sample, and wherein the draw flow rate is from about 0.001 ml/min to about 2 ml/min.

20. The method of claim 16, wherein the four or more different predetermined flow rates comprise a flush flow rate associated with passing a solution past the analyte sensor, and wherein the flush flow rate is from about 0.25 μ

l/min to about 10 ml/min.

21. The method of claim 16, wherein the four or more predetermined flow rates comprise a reference measurement flow rate associated with measuring the signal associated with the analyte concentration of the solution, and wherein the reference measurement flow rate is about 0 ml/min.

22. The method of claim 16, wherein the four or more predetermined flow rates comprise a slow flow rate associated with passing a solution past the analyte sensor, and wherein the slow flow rate is from about 1.0 μ

l/min to about 1.0 ml/min.

23. The method of claim 16, wherein the four or more predetermined flow rates comprise a free flow rate associated with passing a solution past the analyte sensor, wherein the free flow rate comprises free flow of the solution through the flow control device.

24. A method for measuring a concentration of an analyte in a circulatory system of a host, the method comprising:

providing an analyte measuring system comprising a vascular access device, an analyte sensor configured to measure an analyte concentration, and electronics operatively connected to the analyte sensor and configured to generate a signal associated with the analyte concentration, wherein the analyte sensor is configured to reside within the vascular access device, and wherein the vascular access device and the analyte sensor are configured for fluid communication with the circulatory system;

passing a solution past the analyte sensor and measuring a signal associated with an analyte concentration of the solution; and

drawing back a sample from the circulatory system and measuring a signal associated with the analyte concentration of the sample, wherein the analyte measuring system further comprises a flow control device, wherein the flow control device is configured to meter flow during passing and drawing, wherein the flow control device comprises a valve comprising a first discrete position and a second discrete position, wherein passing a solution comprises passing a volume of less than 50 microliters during movement of the valve from the first position to the second position.

25. A method for measuring a concentration of an analyte in a circulatory system of a host, the method comprising:

providing an analyte measuring system comprising a vascular access device, an analyte sensor configured to measure an analyte concentration, and electronics operatively connected to the analyte sensor and configured to generate a signal associated with the analyte concentration, wherein the analyte sensor is configured to reside within the vascular access device;

placing the vascular access device and the analyte sensor in fluid communication with the circulatory system;

passing a solution past the analyte sensor and measuring a signal associated with an analyte concentration of the solution; and

drawing back a sample from the circulatory system and measuring a signal associated with an analyte concentration of the sample, wherein drawing back the sample from the circulatory system comprises drawing back the sample into the vascular access device substantially no farther than a plane defined by a skin of the host.

26. The method of claim 25, wherein passing a solution comprises passing the solution at a first flow rate of from about 0.001 ml/min to about 2 ml/min.

27. The method of claim 26, wherein the first flow rate is from about 0.02 ml/min to about 0.35 ml/min.

28. The method of claim 25, further comprising keeping the vein open by passing the solution past the analyte sensor at a predetermined flow rate.

29. The method of claim 28, wherein the predetermined flow rate is from about 1 μ

l/min to about 1 ml/min.

30. The method of claim 29, wherein the predetermined flow rate is from about 0.02 ml/min to about 0.2 ml/min.

31. The method of claim 25, wherein the analyte is glucose, and wherein measuring the concentration of the analyte comprises measuring a glucose concentration.

32. The method of claim 25, wherein drawing back a sample comprises drawing back a sample at a flow rate of from about 0.001 ml/min to about 2 ml/min.

33. The method of claim 25, wherein placing the vascular access device in fluid communication with a vein comprises placing the vascular access device in a central vein.

34. The method of claim 25, wherein drawing back a sample comprises drawing back a sample volume of less than about 500 microliters.

35. The method of claim 25, wherein drawing back a sample comprises drawing back a sample volume of less than about 150 microliters.

36. A method for measuring a concentration of an analyte in a vein of a host, the method comprising:

providing an analyte measuring system comprising a vascular access device, an analyte sensor configured to measure an analyte concentration and configured to reside within the vascular access device, and electronics operatively connected to the sensor and configured to generate a signal associated with the analyte concentration;

placing the vascular access device and the analyte sensor in fluid communication with a vein of a host;

passing a solution past the analyte sensor and measuring a signal associated with an analyte concentration of the solution; and

drawing back a sample volume of from about 25 μ

l to about 150 μ

l from the vein, measuring a signal associated with the analyte concentration of the sample and subsequently returning the sample back to the vein, wherein the vascular access device comprises a catheter and tubing connected to the catheter.

37. The method of claim 36, wherein drawing back a sample volume comprises drawing back the sample volume into the catheter, but not into the tubing.

38. The method of claim 36, wherein the analyte is glucose, and wherein measuring the concentration of the analyte comprises measuring a glucose concentration.

39. The method of claim 36, wherein drawing back a sample comprises drawing back a sample at a flow rate of from about 0.001 ml/min to about 2 ml/min.

40. The method of claim 36, wherein placing the vascular access device in fluid communication with a vein comprises placing the vascular access device in a central vein.