Method and system for assessing collateral blood flow to a tissue region of interest

• US 6,540,688 B1
• Filed: 10/11/2001
• Issued: 04/01/2003
• Est. Priority Date: 10/11/2001
• Status: Expired due to Term

• Current Assignee: Datex-Ohmeda Incorporated (GE Healthcare Technologies, Inc.)
• Original Assignee: Datex-Ohmeda Incorporated (GE Healthcare Technologies, Inc.)
• Inventors: Pologe, Jonas A., Gingrich, Matthew A.
• Primary Examiner(s): Hindenburg, Max F.
• Assistant Examiner(s): Natnithithadha, Navin
• Application Number:
  US09/976,636
• Publication Number:
  US 20030073913A1
• Time in Patent Office: 537 Days
• Field of Search: 600/504, 600/505, 600/507, 600/500, 600/481, 600/483, 600/485, 600/310, 600/473, 600/476, 600/477, 600/478, 600/479, 600/480
• US Class Current: 600/504
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light

Abstract

The present invention is directed to a method and system for use in assessing collateral blood flow to a tissue region of interest (ROI). The method includes the steps of obtaining a first pulsatility measurement and a second pulsatility measurement, wherein one of the pulsatility measurements is obtained with a plurality of arteries supplying blood to the tissue ROI and the other pulsatility measurement is obtained with at least a selected one of such arteries substantially occluded. The method further provides for use of the first and second pulsatility measurements to generate a collateral flow value useful to medical personnel as an objective measure in assessing collateral blood flow to a tissue ROI. The method may further include the step of obtaining a check pulsatility measurement after obtaining a first pulsatility measurement and prior to obtaining a second pulsatility measurement, wherein all of the plurality of the arteries are substantially occluded. The check procedure enhances the reliability of a second pulsatility measurement obtained when a selected one of the arteries is substantially occluded.

Claims

1. A method for use in assessing collateral blood flow to a tissue region of interest, comprising:

obtaining at least a first pulsatility measurement and a second pulsatility measurement indicative of the volume of blood flow to a tissue region of interest, wherein one of said first and second pulsatility measurements is obtained with a plurality of arteries supplying blood to the tissue region of interest, and wherein the other of said first and second pulsatility measurements is obtained with at least one of said plurality of arteries substantially occluded; and

,

employing said first pulsatility measurement and said second pulsatility measurement to obtain a value employable to assess collateral blood flow to the tissue region of interest.

2. A method as recited in claim 1, further comprising:

making a check pulsatility measurement indicative of the volume of blood flow to the tissue region of interest, wherein the check pulsatility measurement is obtained with each of said plurality of arteries substantially occluded.

3. A method as recited in claim 2, further comprising:

comparing said check pulsatility measurement with a check reference range, wherein the obtainment of a check pulsatility measurement within said check reference range is a condition precedent to the obtainment of said second pulsatility measurement.

4. A method as recited in claim 3, further comprising;

utilizing said first pulsatility measurement to determine said check reference range.

5. A method as recited in claim 1, said obtaining step comprising:

passing at least a first light signal through the tissue region of interest;

detecting a portion of said first light signal transmitted through said tissue region of interest; and

,

using said detected light signal to generate said first pulsatility measurement and said second pulsatility measurement value.

6. A method as recited in claim 5, wherein said using step is performed by a photoplethysmographic device.

7. A method as recited in claim 5, said employing step comprising:

storing said first pulsatility measurement and said second pulsatility measurement for use in the obtainment of a collateral blood flow value.

8. A method as recited in claim 7, wherein said collateral blood flow value is a ratio of the first pulsatility measurement and said second pulsatility measurement.

9. A method as recited in claim 7, further comprising:

outputting said collateral blood flow value to a user.

10. A method as recited in claim 7, wherein said first pulsatility measurement and said second pulsatility measurement are obtained during non-overlapping first and second time periods, respectively, and further comprising:

prompting a user at one or both of the beginning and ending of at least one of said first measurement period and said second measurement period.

11. A method as recited in claim 10, said prompting step comprising:

providing at least one of a visual signal and an audible signal to a user.

12. A method as recited in claim 7, said obtaining step further comprising:

first obtaining a first plurality of pulsatility values; and

first determining said first pulsatility measurement utilizing said plurality of pulsatility values.

13. A method as recited in claim 12, said obtaining step further comprising:

second obtaining a second plurality of pulsatility values; and

second determining said second pulsatility measurement utilizing said second plurality of pulsatility values.

14. A method as recited in claim 13, said obtaining step further comprising:

first comparing said first plurality of pulsatility values to a first reference range, wherein when all of said first plurality of pulsatility values are within said first reference range said first determining step is completed.

15. A method as recited in claim 14, wherein when any of said first plurality of pulsatility values are outside of said first reference range then first obtaining step is repeated.

16. A method as recited in claim 14, said obtaining step further comprising:

second comparing said second plurality of pulsatility values to a second reference range, wherein when all of said second plurality of pulsatility values are within said second reference range said second determining step is completed.

17. A method as recited in claim 16, wherein when any of said second plurality of pulsatility values are outside of said second reference range then second obtaining step is repeated.

18. A method as recited in claim 16, further comprising:

obtaining a check pulsatility measurement indicative of the volume of blood flow to the tissue region of interest, wherein the check pulsatility measurement is obtained with each of said plurality of arteries substantially occluded; and

,

comparing said check pulsatility measurement to a check reference range, wherein when said check pulsatility measurement is within said check reference range said second pulsatility measurement is obtained.

19. A method as recited in claim 18, further comprising:

utilizing said first pulsatility measurement to determine said check reference range.

20. A system for use with a photoplethysmographic sensor that provides an output signal indicative of the amount of a light signal transmitted through a tissue region of interest, comprising:

pulsatility means for using said sensor output signal to obtain a first pulsatility measurement and a second pulsatility measurement, wherein said first pulsatility measurement is obtained with a plurality of arteries supplying blood to the tissue region of interest, and wherein said second pulsatility measurement is obtained with at least a selected one of said plurality of arteries substantially occluded; and

,

collateral flow means for utilizing said first pulsatility measurement and said second pulsatility measurement to compute a collateral blood flow value indicative of collateral blood flow to said tissue region of interest.

21. A system as recited in claim 20, wherein said system is operable in at least a first mode to measure at least one blood analyte concentration value and in a second mode to obtain said collateral blood flow value, and wherein said system further comprises:

a user interface selection means for allowing a user to select one of said first mode and said second mode of operation.

22. A system as recited in claim 20, wherein said user interface is further operable to output said collateral blood flow value to a user.

23. A system as recited in claim 20, wherein said pulsatility means is operable to automatically obtain a first plurality of pulsatility values and to automatically compute said first pulsatility measurement utilizing said first plurality of pulsatility values.

24. A system as recited in claim 23, wherein said pulsatility means is further operable to automatically obtain a second plurality of pulsatility values and to automatically utilize said second plurality of pulsatility values to compute said second pulsatility measurement.

25. A system as recited in claim 24, wherein said pulsatility means is further operable to obtaining a check pulsatility measurement, wherein said check pulsatility measurement is obtained with each of the plurality of arteries substantially occluded, and wherein said pulsatility means obtains said second pulsatility measurement when said check pulsatility measurement is determined to fall within a check reference range.

26. A system as recited in claim 24, wherein said user interface is further operable to provide a series of user output prompts for completing a collateral blood flow test procedure.

27. A system as recited in claim 26, wherein said series of user output prompts comprise instructions for occluding and opening said plurality of arteries in corresponding relation to said obtainment of said first pulsatility measurement, said second pulsatility measurement and said check pulsatility measurement.