METHOD AND APPARATUS FOR DETECTION OF VENOUS PULSATION

• US 20120123282A1
• Filed: 01/17/2012
• Published: 05/17/2012
• Est. Priority Date: 09/27/2006
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Nellcor Puritan Bennett LLC (Medtronic Plc)
• Inventors: Baker, Clark R. Jr.
• Granted Patent: US 8,632,472 B2
• Time in Patent Office: Days
• US Class Current: 600/500
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives

Abstract

Methods and systems for detecting venous pulsation are provided. In one embodiment, a metric of the pulse shape of one or more plethysmographic signals is derived and the presence of venous pulsation is detected based on the metric of pulse shape. Examples, of metrics of pulse shape include a skew metric and a ratio of a minima-to-maxima time over a pulse period interval. In an exemplary embodiment, the presence of venous pulsation is detected based on a metric of the pulse shape of one or more plethysmographic signals and on a phase comparison of the plethysmographic signals.

Claims

1. A method for detecting venous pulsation, comprising:

deriving a metric of the pulse shape of one or more plethysmographic signals;

deriving a phase comparison of the plethysmographic signals; and

detecting the presence of venous pulsation based on the metric of the pulse shape and the phase comparison.

2. The method of claim 1, wherein the metric of the pulse shape comprises a measure of the skewness of the derivative of the one or more plethysmographic signals.

3. The method of claim 1, wherein the phase comparison comprises a measure of the openness of a Lissajous plot formed by comparing the one or more plethysmographic signals.

4. The method of claim 1, wherein the metric of the pulse shape comprises the ratio of a minima-to-maxima time over an entire pulse period interval of the one or more plethysmographic signals.

5. The method of claim 1, wherein detecting the presence of venous pulsation comprises combining the metric of the pulse shape and the phase comparison to calculate a venous pulsation metric.

6. The method of claim 5, wherein detecting the presence of venous pulsation comprises comparing the venous pulsation metric to a threshold value.

7. The method of claim 1, further comprising providing a notification of the presence of venous pulsation when detected.

8. One or more tangible, machine readable media, comprising code executable to perform the acts of:

deriving a metric of the pulse shape of one or more plethysmographic signals;

deriving a phase comparison of the plethysmographic signals; and

detecting the presence of venous pulsation based on the metric of the pulse shape and the phase comparison.

9. The tangible, machine readable media of claim 8, wherein the metric of the pulse shape comprises a measure of the skewness of the derivative of the one or more plethysmographic signals.

10. The tangible, machine readable media of claim 8, wherein the phase comparison comprises a measure of the openness of a Lissajous plot formed by comparing the one or more plethysmographic signals.

11. The tangible, machine readable media of claim 8, wherein the metric of the pulse shape comprises the ratio of a minima-to-maxima time over an entire pulse period time of the one or more plethysmographic signals.

12. The tangible, machine readable media of claim 8, further comprising code executable to perform the acts of combining the metric of the pulse shape and the phase comparison to calculate a venous pulsation metric.

13. The tangible, machine readable media of claim 12, further comprising code executable to perform the acts of comparing the venous pulsation metric to a threshold value.

14. The tangible, machine readable media of claim 8, further comprising code executable to perform the acts of providing a notification of the presence of venous pulsation when detected.

15. A patient monitoring system comprising:

a patient monitor configured to;

derive a metric of the pulse shape of one or more plethysmographic signals;

derive a phase comparison of the plethysmographic signals; and

detect the presence of venous pulsation based on the metric of the pulse shape and the phase comparison.

16. The system of claim 15, wherein the metric of the pulse shape comprises a measure of the skewness of the derivative of the one or more plethysmographic signals.

17. The system of claim 15, wherein the phase comparison comprises a measure of the openness of a Lissajous plot formed by comparing the one or more plethysmographic signals.

18. The system of claim 15, wherein the metric of the pulse shape comprises the ratio of a minima-to-maxima time over an entire pulse period time of the one or more plethysmographic signals.

19. The system of claim 15, wherein detecting the presence of venous pulsation comprises combining the metric of the pulse shape and the phase comparison to calculate a venous pulsation metric.

20. The system of claim 15, wherein detecting the presence of venous pulsation comprises comparing the venous pulsation metric to a threshold value.

21. The system of claim 15, wherein the patient monitor is configured to provide a notification of the presence of venous pulsation when detected.