Method and Apparatus for Photostimulation Enhanced Analyte Property Estimation

• US 20070149868A1
• Filed: 10/04/2006
• Published: 06/28/2007
• Est. Priority Date: 03/08/2002
• Status: Abandoned Application

• Current Assignee: Sensys Medical, Inc. (Sensys Medical Limited)
• Original Assignee: Sensys Medical, Inc. (Sensys Medical Limited)
• Inventors: Blank, Thomas, Monfre, Stephen, Mattu, Mutua, Markarewicz, Marcy
• Application Number:
  US11/538,737
• Publication Number:
  US 20070149868A1
• Time in Patent Office: Days
• US Class Current: 600/316
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/1491 Heated applicators
• CPC Class Codes: A61N 5/0613 Apparatus adapted for a specific treatment

Abstract

A method and apparatus using photostimulation to treat or pretreat a sample site prior to analyte property estimation is presented. More particularly, photonic-stimulation at and/or near at least one sample site is used to enhance perfusion of the sample site leading to reduced errors associated with sampling. This allows an analyte property determination in well perfused regions of the body while sampling at a more convenient less well perfused region of the body.

Claims

1. A method for analyte property determination at a tissue sample site of a human subject, comprising the steps of:

generating a calibration from samples collected from well perfused tissue;

enhancing perfusion at the sample site by photostimulation at or near the sample site with a first photon source;

noninvasively measuring a spectrum from the sample site, wherein said step of measuring uses a second photon source; and

estimating said analyte property using said calibration and said spectrum, wherein said calibration generated using samples collected from well perfused sample tissue applies to said spectrum.

2. The method of claim 1, wherein said well perfused tissue comprises tissue from a plurality of calibration subjects, wherein the sample site comprises tissue from a measurement subject.

3. The method of claim 2, wherein said measurement subject is not a member of said plurality of calibration subjects.

4. The method of claim 2, wherein said well perfused tissue comprises tissue from a fingertip or a toe, wherein the sample site comprises a skin/tissue sample that does not comprise a region of the measurement subject'"'"'s fingertip or toe.

5. The method of claim 1, wherein said well perfused tissue comprises any of:

photostimulated tissue;

finger tissue; and

toe tissue.

6. The method of claim 5, wherein the sample site does not comprise a fingertip or a toe.

7. The method of claim 1, wherein the sample site comprises a tissue volume having at least intermittent degradation of tissue perfusion compared to perfusion of a fingertip.

8. The method of claim 1, wherein said step of using a first photon source occurs prior to said measuring step.

9. The method of claim 8, wherein said step of using a first photon source is repeated over a period of at least days to produce angiogenesis at or about the sample site before said step of noninvasively measuring.

10. The method of claim 1, wherein said spectrum represents photons from said second source in the absence of photons from said first source.

11. The method of claim 1, wherein said first source comprises a light emitting diode.

12. The method of claim 11, wherein said second source comprises a broadband source.

13. The method of claim 1, wherein said calibration comprises a multivariate model.

14. The method of claim 13, wherein said multivariate model uses at least one reading from each of at least ten wavelengths.

15. The method of claim 1, further comprising a step of using a second perfusion enhancement technique, wherein said photostimulation step occurs within four hours prior to said noninvasively measuring step, wherein said second perfusion enhancement technique is used after said photostimulation step, and wherein said second perfusion enhancement technique comprises any of:

applying additional heat to the sample site beyond that of photostimulation to the sample site;

rubbing at or about the sample site;

ingestion, by the subject, of L-arginine;

ingestion, by the subject, of a surface capillary dilating agent;

applying a negative pressure at or about the sample site; and

application of a topical vasodilating agent at the sample site.

16. The method of claim 1, wherein said well perfused tissue comprises tissue that is intermittently not well perfused, wherein said tissue that is not well perfused is subjected to photostimulation prior to generation of said calibration to enhance perfusion.

17. A method for analyte property determination at a sample site of a human subject, comprising the steps of:

enhancing perfusion at the sample site by photostimulating about the sample site;

enhancing perfusion of the sample site with a second technique, wherein said second technique is used within four hours of said photostimulating step; and

determining said analyte property with either an invasive apparatus or a noninvasive apparatus after said steps of photostimulating.

18. The method of claim 17, wherein said second technique comprises any of:

applying additional heat beyond that of photostimulation to the sample site;

rubbing at or about the same site;

19. The method of claim 17, wherein said second technique comprises intake of L-arginine by the subject.

20. The method of claim 17, wherein said second technique comprises any of:

intake of a surface capillary dilating agent by the subject;

applying a negative pressure at or about the sample site; and

application of a topical pharmacologic or vasodilating agents to the sample site.

21. The method of claim 17, further comprising the step of:

determining a glucose concentration of the subject in a biological sample collected from a body part of the subject comprising any of;

a forearm;

an upper arm;

a head;

a torso;

an abdominal region;

a thigh; and

a calf.

22. The method of claim 21, wherein said invasive apparatus comprises an alternative invasive apparatus, wherein said alternative invasive apparatus acquires a biological sample from the subject using any of:

laser poration;

applied current; and

a partial vacuum.

23. A method for analyte property determination at a sample site, of a human subject comprising the steps of:

enhancing perfusion at the sample site by photostimulating a region about the sample site;

noninvasively determining said analyte property at the sample site, wherein said determining step is performed within a period of four hours following said photostimulating step, wherein said noninvasively determining step uses at least one wavelength of incident light not used in said photostimulating step.

24. A method for analyte property determination at a sample site of a human subject, comprising the steps of:

enhancing perfusion at the sample site by photostimulating with a light emitting diode at or about the sample site;

noninvasively determining said analyte property at said photostimulated sample site, wherein said determining step is performed using a photon source having a total spectral range in excess of 300 nm, wherein said determining step occurs within four hours of said photostimulating step.

25. An apparatus for analyte property determination at a tissue sample site of a human subject comprising:

a first photon source for photostimulation at or near the sample site to enhance perfusion at the sample site; and

an analyzer comprising a calibration generated using samples collected from well perfused tissue, said analyzer comprising a second photon source, means for measuring a spectrum from the sample site, and means for estimating said analyte property using said calibration and said spectrum,

wherein samples collected from well perfused sample tissue are used to generate said calibration that is applied to said spectrum.

26. The apparatus of claim 25, wherein said first photon source comprises at least one light emitting diode, and said second photon source comprises a broadband source providing light over a wavelength range of at least 300 nm.

27. The apparatus of claim 25, wherein said analyzer further comprises:

a sample probe tip; and

means for z-axis control of said sample probe tip relative to the sample site.

28. The apparatus of claim 26, wherein said analyzer further comprises:

means for tilt control of at least a portion of said analyzer relative to the sample site.

29. The apparatus of claim 25, wherein said analyzer further comprises a multivariate model, wherein said multivariate model receives as an input at least one reading from each of at least ten wavelengths.

30. The apparatus of claim 25, wherein said analyzer further comprises a second means for enhancing perfusion at the sample site.

31. The apparatus of claim 25, wherein said first photon source for photostimulation is integrated into said analyzer.