Pulse oxymetry data processing

• US 6,668,182 B2
• Filed: 01/10/2002
• Issued: 12/23/2003
• Est. Priority Date: 01/10/2002
• Status: Active Grant

• Current Assignee: Northeast Monitoring
• Original Assignee: Northeast Monitoring
• Inventors: Hubelbank, Mark
• Primary Examiner(s): Winakur, Eric F.
• Assistant Examiner(s): KREMER, MATTHEW J
• Application Number:
  US10/044,135
• Publication Number:
  US 20030130584A1
• Time in Patent Office: 712 Days
• Field of Search: 600/309-310, 600/322-323, 600/336
• US Class Current: 600/323
• CPC Class Codes: A61B 5/00 Measuring for diagnostic purposes radiation diagnosis A61B6/00; diagnosis by ultrasonic, sonic or infrasonic waves A61B8/00; Identification of persons
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/14551 for measuring blood gases

Abstract

In one aspect, the invention is a method for processing pulse oxymetry data signals. The method includes recording pulse oxymetry data signals. The pulse oxymetry data signals have a plurality of oxymetry waveforms. The method also includes determining a correlation coefficient between sequential oxymetry waveforms and identifying a valid pulse oxymetry waveform.

Claims

1. A method for processing pulse oxymetry data signals, comprising:

recording pulse oxymetry data signals. the pulse oxymetry data signals having a plurality of oxymetry waveforms, the pulse oxymetry data signals corresponding to oxygen saturation data signals;

determining a correlation coefficient between sequential oxymetry waveforms; and

identifying a valid pulse oxymetry waveform;

wherein determining the correlation coefficient comprises;

storing a first pulse oxymetry waveform segment having a first length in a first buffer;

copying said first pulse oxymetry waveform segment from said first buffer to a second buffer;

copying a second pulse oxymetry waveform segment having a second length to said first buffer;

comparing the first length, the second length and a predetermined value; and

determining a correlation length related to said first and second lengths and said predetermined value.

2. The method of claim 1, wherein determining a correlation length comprises taking the minimum of the first length, the second length, and the predetermined value.

3. The method of claim 1, wherein determining a correlation coefficient comprises:

determining a correlation coefficient from the first pulse oxymetry waveform segment and the second pulse oxymetry waveform segment;

comparing the correlation coefficient to a threshold value; and

filtering out an invalid pulse oxymetry waveform segment that has a correlation coefficient below the threshold value.

4. The method of claim 3, wherein filtering out the invalid pulse oxymetry waveform segment comprises eliminating pulse oxymetry waveform segments if 75% of the correlation coefficients for the last 6 seconds are above the threshold value of 0.9.

5. The method of claim 1, further comprising determining valid oxygen desaturation data signals.

6. The method of claim 5, wherein determining valid desaturation signals comprises labeling oxygen saturation signals below a threshold value for a predetermined time as valid desaturation data.

7. The method of claim 6, wherein the threshold value is 88% oxygen saturation and the predetermined time is 300 seconds.

8. The method of claim 6, wherein determining valid desaturation signals comprises eliminating artifacts.

9. The method of claim 6, wherein determining valid desaturation signals comprises ignoring desaturation signals below the threshold value that do not reach a peak value.

10. An apparatus for processing pulse oxymetry data signals, comprising:

a memory that stores executable instruction data signals; and

a processor that executes the instruction data signals to;

record the pulse oxymetry data signals, the pulse oxymetry data signals having a plurality of oxymetry waveforms, the pulse oxymetry data signals corresponding to oxygen saturation data signals;

determine a correlation coefficient between sequential oxymetry waveforms; and

identify an valid pulse oxymetry waveform;

wherein to determine the correlation coefficient comprises;

storing a first pulse oxymetry waveform segment having a first length in a first buffer;

copying said first pulse oxymetry waveform segment from said first buffer to a second buffer;

copying a second pulse oxymetry waveform segment having a second length to said first buffer;

comparing the first length, the second length and a predetermined value; and

determining a correlation length related to said first and second lengths and said predetermined value.

11. The apparatus of claim 10, wherein determining a correlation length comprises taking the minimum of the first length, the second length, and the predetermined value.

12. The apparatus of claim 10, wherein to determine a correlation coefficient comprises:

determining a correlation coefficient from the first pulse oxymetry waveform segment and the second pulse oxymetry waveform segment;

comparing the correlation coefficient to a threshold value; and

filtering out an invalid pulse oxymetry waveform segment, the invalid pulse oxymetry waveform segment having correlation coefficient below the threshold value.

13. The apparatus of claim 12, wherein filtering out the invalid pulse oxymetry waveform segment comprises eliminating pulse oxymetry waveform segments if 75% of the correlation coefficients for the last 6 seconds are above the threshold value of 0.9.

14. The apparatus of claim 10, further comprising instruction data signals to determine valid oxygen desaturation data signals.

15. The apparatus of claim 14, wherein to determine valid desaturation signals comprises labeling oxygen saturation signals below a threshold value for a predetermined time as valid desaturation data.

16. The apparatus of claim 15, wherein the threshold value is 88% oxygen saturation and the predetermined time is 300 seconds.

17. The apparatus of claim 15, wherein to determine valid desaturation signals comprises eliminating artifacts.

18. The apparatus of claim 15, wherein to determine valid desaturation signals comprises ignoring desaturation signals below the threshold value that do not reach a peak value.

19. An article comprising a machine-readable medium that stores executable instruction signals for processing pulse oxymetry data signals, the instruction signals causing a machine to:

record the pulse oxymetry data signals, the pulse oxymetry data signals having a plurality of oxymetry waveforms, the pulse oxymetry data signals corresponding to oxygen saturation data signals;

determine a correlation coefficient between sequential oxymetry waveforms; and

identify a valid pulse oxymetry waveform;

wherein to determine the correlation coefficient comprises;

storing a first pulse oxymetry waveform segment having a first length in a first buffer;

copying said first pulse oxymetry waveform segment from said first buffer to a second buffer;

copying a second pulse oxymetry waveform segment having a second length to said first buffer;

comparing the first length, the second length and a predetermined value; and

determining a correlation length related to said first and second lengths and said predetermined value.

20. The article of claim 19, wherein determining a correlation length comprises taking the minimum of the first length, the second length, and the predetermined value.

21. The article of claim 19, wherein to determine a correlation coefficient comprises:

determining a correlation coefficient from the first pulse oxymetry waveform segment and the second pulse oxymetry waveform segment;

comparing the correlation coefficient to a threshold value; and

filtering out an invalid pulse oxymetry waveform segment, the invalid pulse oxymetry waveform segment having correlation coefficient below the threshold value.

22. The article of claim 21, wherein filtering out the invalid pulse oxymetry waveform segment comprises eliminating pulse oxymetry waveform segments if 75% of the correlation coefficients for the last 6 seconds are above the threshold value of 0.9.

23. The article of claim 21, further comprising instruction signals causing a machine to:

determine valid oxygen desaturation data signals.

24. The article of claim 23, wherein to determine valid desaturation signals comprises labeling oxygen saturation signals below a threshold value for a predetermined time as valid desaturation data.

25. The article of claim 24, wherein the threshold value is 88% oxygen saturation and the predetermined time is 300 seconds.

26. The article of claim 24, wherein to determine valid desaturation signals comprises eliminating artifacts.

27. The article of claim 24, wherein to determine valid desaturation signals comprises ignoring desaturation signals below the threshold value that do not reach a peak value.