CLINICAL APPLICATIONS OF STO2 ANALYSIS

• US 20070203406A1
• Filed: 02/27/2007
• Published: 08/30/2007
• Est. Priority Date: 02/27/2006
• Status: Active Grant

• Current Assignee: Hutchinson Technology Incorporated (TDK Corporation)
• Original Assignee: Hutchinson Technology Incorporated (TDK Corporation)
• Inventors: Myers, Dean, Ortner, Joseph, Wheatley, Gregory, Anderson, LeAnn
• Granted Patent: US 8,208,983 B2
• Time in Patent Office: Days
• US Class Current: 600/323
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/412 Detecting or monitoring sepsis

Abstract

Embodiments of the invention provide a method and apparatus for using StO₂ values to predict an outcome of a subject'"'"'s health status.

Claims

1. A method for predicting a health status of a subject, comprising:

measuring the levels of hemoglobin oxygenation (StO₂) in tissue of the subject;

comparing the measured levels to a threshold value; and

predicting the status of the subject, wherein levels of hemoglobin oxygenation above the threshold value is associated with a first health status, and levels of hemoglobin oxygenation below the threshold value is associated with a second health status.

2. The method of claim 1 wherein the measuring of StO₂ is measuring on a thenar eminence muscle of a hand.

3. The method of claim 1 wherein the measuring of the StO₂ is by spectroscopic radiation.

4. The method of claim 3 wherein the spectroscopic radiation is near infrared radiation.

5. The method of claim 1 wherein the first health status is a lower risk or probability of developing an adverse health outcome.

6. The method of claim 1 wherein the second health status is a higher risk or probability of developing an adverse health outcome.

7. The method of claim 6 wherein the adverse health outcome is ischemia, hypoperfusion, hypoxia, oxygen debt death, multiple organ dysfunction, ventilator-free days or number of hospitalization days.

8. The method of claim 1 wherein the threshold value is a minimum StO₂ value.

9. The method of claim 8 wherein the minimum StO₂ value is 75 percent.

10. The method of claim 1 further predicting a future health status of the subject, comprising comparing the levels of hemoglobin oxygenation that is generally trending above the threshold value and is associated with a third health status, and levels of hemoglobin oxygenation that is generally trending below the threshold value and is associated with a fourth health status.

11. The method of claim 10 wherein the trending of the threshold value is determined by a net tissue oxygenation cumulative area or cumulative ischemia score.

12. The method of claim 11 wherein the net tissue oxygenation cumulative area or cumulative ischemia score is calculated using the equation:

13. The method of claim 10 wherein the fourth health status is ischemia, hypoperfusion, hypoxia, oxygen debt death, multiple organ dysfunction, ventilator-free days or number of hospitalization days.

14. The method of claim 1 wherein the threshold value is set by a physician or end user.

15. The method of claim 1 wherein the threshold value of 50 percent StO₂ indicates a highest probability of developing an adverse health outcome.

16. An apparatus for predicting a subject'"'"'s health status based on a measure of hemoglobin oxygen saturation (StO₂) comprising:

a subject interface comprising a light path for irradiating tissue of the subject with spectroscopic radiation and a detector for detecting a spectral response from the tissue responsive to irradiation with the spectroscopic radiation;

a display for displaying data;

memory storing a predetermined threshold value limit; and

a processor operatively connected to the memory and the subject interface such that the processor generates data from information comprising the spectral response of the tissue sample in a pre-selected format;

the processor issuing a signal to indicate when a measured StO₂ data is outside of a pre-determined threshold or range.

17. The apparatus of claim 16 wherein the subject interface is placed on a thenar eminence.

18. The apparatus of claim 16 wherein the pre-determined threshold value is a minimum StO₂.

19. The apparatus of claim 18 wherein the minimum StO₂ value limit is 75 percent.

20. The apparatus of claim 18 wherein a threshold of 50 percent StO₂ signals a highest probability of developing an adverse health outcome.

21. The apparatus of claim 16 wherein the memory further includes a data representative of a correlation which provides the relative concentration of the oxygenated hemoglobin as a function of a scaled, second derivative spectrum value input, wherein the scaled second derivative value input is derived from the spectral response obtained from the tissue sample at a plurality of wavelengths within a wavelength range from 600 nm to 900 nm.

22. The apparatus of claim 16 wherein the apparatus further signals to indicate when StO₂ levels are generally trending above or below the threshold value.

23. The apparatus of claim 16 wherein the trending of StO₂ levels is determined by a net tissue oxygenation cumulative area or cumulative ischemia score.

24. The apparatus of claim 23 wherein the net tissue oxygenation cumulative area or cumulative ischemia score is calculated using the equation:

25. The apparatus of claim 16 wherein a threshold can be adjusted according to the end user.

26. A device for predicting a subject'"'"'s health status based on a measure of hemoglobin oxygen saturation comprising:

means for sensing including a light source assembly for generating spectroscopic radiation for irradiating a tissue and a spectroscopic detector for detecting a spectral response emitted by the tissue sample responsive to irradiation with the spectroscopic radiation;

means for displaying data;

means for providing a notice to a user upon the occurrence of a specified event;

means for storing, said means for storing including a predetermined threshold or range;

a means for generating data of the tissue sample from information comprising the spectral response of the tissue sample;

a means for characterizing the data in a pre-selected form including a control system interfaced with the means for storing and the means for sensing such that the control system generates data of the tissue sample; and

a means to indicate when a measured StO₂ data is outside of the pre-determined threshold or range.

27. A method of determining a relationship between StO₂ and a health status of a subject comprising;

monitoring the subject'"'"'s StO₂ for a period;

storing the subject'"'"'s StO₂ measurements versus time to form an StO₂ curve;

determining an area between the StO₂ curve and a threshold; and

determining whether the subject is likely to develop a first health status if the area is above the threshold or generally trending above the threshold, or likely to develop a second health status if the area is below the threshold or generally trending below the threshold.

28. The method of claim 27 wherein the first health status is a lower risk or probability of developing an adverse health outcome.

29. The method of claim 27 wherein the second health status is a higher risk or probability of developing an adverse health outcome.

30. The method of claim 27 wherein the threshold is a minimum StO₂ value.

31. The method of claim 30 wherein the minimum StO₂ value is 75 percent.

32. The method of claim 27 wherein the relationship between the StO₂ and the health status is determined based on a net tissue oxygenation cumulative area or cumulative ischemia score.

33. The method of claim 32 wherein the net tissue oxygenation cumulative area or cumulative ischemia score is calculated using the equation:

34. The method of claim 27 wherein the threshold is pre-set by the user.

35. The method of claim 27 wherein a physician or end-user may elect to treat the subject to affect or change the StO₂ depending on the health status of the subject.

36. The method of claim 27 wherein the storing is storing is storing StO2 in the form of graphs.