Diagnosing peripheral vascular disease by monitoring oxygen saturation changes during an accumulation phase

1. A method of diagnosing peripheral vascular disease comprising:

measuring oxygen saturation in tissue of a patient during an accumulation phase prior to ischemia;

analyzing the oxygen saturation in the tissue during the accumulation phase; and

diagnosing the patient as having peripheral vascular disease according to changes in the oxygen saturation in the tissue during the accumulation phase.

2. The method of claim 1 wherein the analyzing the oxygen saturation comprises calculating a rate of change of oxygen saturation during the accumulation phase.

3. The method of claim 2 wherein the rate of change is calculated at a midpoint of the accumulation phase.

4. The method of claim 2 wherein the diagnosing the patient comprises determining if the rate of change crosses a threshold.

5. The method of claim 1 wherein the analyzing the oxygen saturation comprises calculating a time for oxygen saturation to reach a specified percentage during the accumulation phase.

6. The method of claim 5 wherein the diagnosing the patient comprises determining if the time for oxygen saturation to reach a specified percentage crosses a threshold.

7. The method of claim 1 wherein the analyzing the oxygen saturation comprises:

calculating a rate of change of oxygen saturation during the accumulation phase; and

calculating a time for oxygen saturation to reach a specified percentage during the accumulation phase.

8. The method of claim 7 wherein the diagnosing the patient comprises determining if the rate of change and the time for oxygen saturation during the accumulation phase cross thresholds.

9. A method comprising:

measuring oxygen saturation of the tissue of the patient during an accumulation phase prior to ischemia; and

diagnosing the patient as having peripheral vascular disease based on changes in the oxygen saturation of the tissue during an accumulation phase before ischemia.

10. The method of claim 9 comprising:

providing a visual indication of a positive diagnosis of peripheral vascular disease on a display when a measured rate of change in the oxygen saturation during an accumulation phase crosses a threshold value.

11. The method of claim 9 comprising

providing a visual indication of a positive diagnosis of peripheral vascular disease on a display when a measured time for the oxygen saturation to cross a percentage value during the accumulation phase exceeds a specific time value.

12. The method of claim 9 comprising:

providing a visual indication of a positive diagnosis of peripheral vascular disease on a display when a measured time, from a starting time value to an ending time value, for the oxygen saturation to cross a percentage value exceeds a specific time value, wherein the ending time is within the accumulation phase.

13. The method of claim 9 comprising:

providing a visual indication of a positive diagnosis of peripheral vascular disease on a display when a measured time, from a starting time value to an ending time value, for the oxygen saturation to cross a percentage value exceeds a specific time value, wherein the starting time is within the accumulation phase.

14. A system for diagnosing peripheral vascular disease comprising:

a probe comprising a first detector input;

a computer, coupled to process signals received via the first detector input, to determine changes in oxygen saturation in tissue of a patient and make a diagnosis of peripheral vascular disease based on the oxygen saturation changes during an accumulation phase;

a pressure cuff, attachable to the patient, to cause the accumulation phase in the patient; and

a display, coupled to the computer, to provide a visual indication of a positive diagnosis of peripheral vascular disease.

15. The system of claim 14 wherein the probe comprises a second detector input and a source output, and a first distance between the first detector input and the source output is different from a second distance between the second detector input and the source output.

16. The system of claim 14 wherein the probe comprises a second detector input, a first source output, and a second source output, and a first distance between the first detector input and the first source output is different from a second distance between the second detector input and the second source output.

17. The system of claim 14 wherein the probe comprises a second detector input, a first source output, and a second source output, and a first distance between the first detector input and the first source output is substantially the same as a second distance between the second detector input and the second source output.

18. A system for diagnosing peripheral vascular disease comprising:

a probe comprising a first detector input;

a computer, coupled to process signals received via the first detector input, to determine changes in oxygen saturation in tissue of a patient and make a diagnosis of peripheral vascular disease based on the oxygen saturation changes during an accumulation phase; and

a display, coupled to the computer, to provide a visual indication of a positive diagnosis of peripheral vascular disease,

wherein the diagnosis of peripheral vascular disease is positive when the computer determines a rate of change in the oxygen saturation crosses a threshold value during the accumulation phase before ischemia.

19. A system for diagnosing peripheral vascular disease comprising:

a probe comprising a first detector input;

a computer, coupled to process signals received via the first detector input, to determine changes in oxygen saturation in tissue of a patient and make a diagnosis of peripheral vascular disease based on the oxygen saturation changes during an accumulation phase; and

a display, coupled to the computer, to provide a visual indication of a positive diagnosis of peripheral vascular disease,

wherein the diagnosis of peripheral vascular disease is positive when a measured time for the oxygen saturation to cross a percentage value during the accumulation phase before ischemia exceeds a specific time value.

20. A system for diagnosing peripheral vascular disease comprising:

a probe comprising a first detector input;

a computer, coupled to process signals received via the first detector input, to determine changes in oxygen saturation in tissue of a patient and make a diagnosis of peripheral vascular disease based on the oxygen saturation changes during an accumulation phase; and

a display, coupled to the computer, to provide a visual indication of a positive diagnosis of peripheral vascular disease,

wherein the diagnosis of peripheral vascular disease is positive when a measured time, from a starting time value to an ending time value, for the oxygen saturation to cross a percentage value exceeds a specific time value, and the ending time is within the accumulation phase before ischemia.

21. A system for diagnosing peripheral vascular disease comprising:

a probe comprising a first detector input;

a computer, coupled to process signals received via the first detector input, to determine changes in oxygen saturation in tissue of a patient and make a diagnosis of peripheral vascular disease based on the oxygen saturation changes during an accumulation phase; and

a display, coupled to the computer, to provide a visual indication of a positive diagnosis of peripheral vascular disease,

wherein the diagnosis of peripheral vascular disease is positive when a measured time, from a starting time value to an ending time value, for the oxygen saturation to cross a percentage value exceeds a specific time value, and the starting time is within the accumulation phase before ischemia.