Apparatus for non-invasive determination of direction and rate of change of an analyte

• US 20060167349A1
• Filed: 01/10/2006
• Published: 07/27/2006
• Est. Priority Date: 08/09/1995
• Status: Active Grant

• Current Assignee: Craig M. Gardner, Trent D. Ridder, William Gruner
• Original Assignee: Craig M. Gardner, Trent D. Ridder, William Gruner
• Inventors: Gruner, William, Ridder, Trent D., Gardner, Craig M.
• Granted Patent: US 7,761,126 B2
• Time in Patent Office: Days
• US Class Current: 600/310
• CPC Class Codes: A61B 2560/0233 Optical standards
• CPC Class Codes: A61B 2562/146 for optical coupling
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/0075 by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy A61B5/0071 takes precedence
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/1491 Heated applicators

Abstract

The present invention relates generally to a non-invasive method and apparatus for measuring a fluid analyte, particularly relating to glucose or alcohol contained in blood or tissue, utilizing spectroscopic methods. More particularly, the method and apparatus incorporate means for detecting and quantifying changes in the concentration of specific analytes in tissue fluid. Also, the method and apparatus can be used to predict future levels of analyte concentration either in the tissue fluid or in blood in an adjacent vascular system.

Claims

1. An apparatus for non-invasive determination of a characteristic of change in an analyte property in tissue, comprising:

a. radiation means for irradiating the tissue;

b. measurement means for measuring a signal from the tissue to acquire a first output signal at a first time, and, after a first time interval, measuring a signal from the tissue to acquire a second output signal;

c. determination means for determining a characteristic of change of the analyte property in the tissue from the first and second output signals.

2. An apparatus according to claim 1, wherein the property is the analyte'"'"'s concentration.

3. An apparatus according to claim 1, wherein the characteristic comprises the rate of change, the direction of change, or a combination thereof.

4. An apparatus according to claim 1, wherein the analyte is glucose.

5. An apparatus according to claim 1, wherein the analyte is urea.

6. An apparatus according to claim 1, wherein the analyte is alcohol.

7. An apparatus according to claim 1, wherein the analyte is a controlled substance.

8. An apparatus according to claim 1, wherein determining a characteristic of change in an analyte property comprises determining a characteristic of change in more than one analyte.

9. An apparatus according to claim 1, wherein the tissue comprises interstitial fluid.

10. An apparatus according to claim 1, wherein the tissue comprises blood.

11. An apparatus according to claim 1, further comprising means for increasing the change in the analyte property.

12. An apparatus according to claim 1, wherein the radiation means comprises means for providing light incident on a first side of the tissue and the measurement means comprises means for receiving light exiting the tissue on a second side of the tissue.

13. An apparatus according to claim 1, wherein the radiation means comprises means for providing light incident on a first side of the tissue and the measurement means comprises means for receiving light exiting the tissue on the first side of the tissue.

14. An apparatus according to claim 1, wherein the measurement means further comprises means for, after a second time interval, measuring a signal from the tissue to acquire a third output signal, and wherein the determination means comprises means for determining a characteristic of change of the analyte property from the first, second, and third output signals.

15. An apparatus for determining a direction and rate of change in concentration of an analyte in tissue comprising:

a. energy means for providing optical energy;

b. input means coupling the optical energy into a tissue sample;

c. output means for capturing an optical signal from the tissue sample; and

d. analyzing means for analyzing the optical signal and determine the direction and rate of change in concentration of the analyte.

16. The apparatus of claim 15, wherein the output means is adapted to modulate the optical signal to enable the analyzing means to analyze a first sample of the optical signal at a first time and a second sample of the optical signal at a second time.

17. The apparatus of claim 15, wherein the analyzing means includes differentiation means for performing the mathematical function of differentiation upon at least one selected frequency of the optical signal over time.

18. An apparatus for measuring changes in concentration of an analyte disposed in tissue comprising:

a. An excitation system adapted to irradiating the tissue;

b. A collection system adapted to capturing radiation at a plurality of selected frequencies emanating from the tissue at a first time and a second time;

c. An analysis system adapted to determining the direction or rate of change, or both, of the concentration of the analyte from the captured radiation.

19. An apparatus according to claim 18, further including an acceleration system adapted to accelerating changes in concentration of the analyte in the tissue during the interval between the first and second times.

20. An apparatus according to claim 18, wherein the analysis system is further adapted to:

a. determining a set of acceptable combinations of present analyte concentration, direction of change, and rate of change of analyte concentration;

b. determining whether the present analyte concentration, direction of change, and rate of change are within the set of acceptable combinations,

c. generating a signal indicative of whether the present analyte concentration, direction of change, and rate of change are within the set of acceptable combinations.