DETECTING CHEMICAL COMPONENTS FROM SPECTROSCOPIC OBSERVATIONS

• US 20130024129A1
• Filed: 09/24/2012
• Published: 01/24/2013
• Est. Priority Date: 03/31/2008
• Status: Abandoned Application

• Current Assignee: Nellcor Puritan Bennett LLC (Medtronic Plc)
• Original Assignee: Nellcor Puritan Bennett LLC (Medtronic Plc)
• Inventors: Pav, Steven E.
• Application Number:
  US13/625,707
• Publication Number:
  US 20130024129A1
• Time in Patent Office: Days
• US Class Current: 702/19
• CPC Class Codes: A61B 5/14551 for measuring blood gases

Abstract

Embodiments disclosed herein may include methods and systems capable of estimating the underlying concentrations of chromophores in a sample. The photon scattering and absorption model may be based on Laplace and stable distributions, which may reveal that measurements in diffuse reflectance may follow a Beer-Lambert and Kohlrausch-Williams-Watts (KWW) product. This Beer-Lambert portion of the product may dominate in high absorption sample areas, while the KWW portion of the product may dominate in low absorption sample areas.

Claims

1. A method for determining the concentration of a component in a tissue sample of a patient, comprising:

collecting a plurality of physiologic signals from a tissue sample of a patient;

measuring, for each physiologic signal, a concentration of a component of the tissue sample; and

performing a Kernel Partial Least Squares regression on the concentration of the component.

2. The method of claim 1, comprising determining a model for the tissue sample based at least in part upon the Kernel Partial Least Squares regression.

3. The method of claim 2, comprising applying the model to a second tissue sample.

4. The method of claim 2, wherein the model comprises a nonlinear model.

5. The method of claim 1, comprising calculating a kernel function for use with the Kernel Partial Least Squares regression.

6. The method of claim 1, wherein collecting the plurality of physiologic signals comprises:

emitting light into the tissue of the patient;

detecting scattered or reflected light from the tissue; and

generating the plurality of physiologic signals corresponding to the detected light.

7. The method of claim 1, wherein the concentration comprises a concentration of chromophores in the tissue sample.

8. A system for determining the concentration of a component in a patient'"'"'s tissue, comprising:

a sensor configured to obtain a plurality of physiologic signals from a patient;

a monitor configured to receive from the sensor the plurality of physiologic signals; and

a processor configured to;

measure, for each physiologic signal, a concentration of a component of the tissue; and

perform a Kernel Partial Least Squares regression on the concentration of the component.

9. The system of claim 8, wherein the sensor is configured to emit light into a tissue of the patient and to detect scattered or reflected light from the tissue.

10. The system of claim 9, wherein the plurality of physiologic signals corresponds to the detected light.

11. The system of claim 8, wherein the monitor comprises a pulse oximeter.

12. The system of claim 8, wherein the processor is configured to determine a model for the tissue based at least in part upon the Kernel Partial Least Squares regression.

13. The system of claim 12, wherein the processor is configured to apply the model to a second tissue sample.

14. The system of claim 12, wherein the model comprises a nonlinear model.

15. The system of claim 8, wherein the processor is configured to calculate a kernel function for use with the Kernel Partial Least Squares regression.

16. The system of claim 8, further comprising a memory device coupled to the processor and storing an assumption regarding the tissue, for use in the Kernel Partial Least Squares regression.

17. The system of claim 8, wherein the concentration comprises a concentration of chromophores in the tissue.

18. A medical device for determining the concentration of a component in a tissue sample, comprising:

a processor configured to;

collect a plurality of physiologic signals from a tissue sample of a patient;

measure, for each physiologic signal, a concentration of a component of the tissue sample; and

perform a Kernel Partial Least Squares regression on the concentration of the component.

19. The medical device of claim 18, wherein the processor is configured to determine a model for the tissue sample based at least in part upon the Kernel Partial Least Squares regression.

20. The medical device of claim 19, wherein the processor is configured to apply the model to a second tissue sample.

21. The medical device of claim 18, wherein the medical device comprises a pulse oximeter.

22. A method for determining a chromophore concentration in a tissue area of a patient, comprising:

emitting electromagnetic radiation into a tissue area of a patient;

detecting radiation scattered and/or reflected by the tissue area;

generating a physiologic signal corresponding to the detected radiation;

collecting a plurality of data samples from the signal;

measuring, for each data sample, an affine function of a chromophore concentration; and

performing a Kernel Partial Least Squares regression to obtain a model for the tissue area.