System and method for venous pulsation detection using near infrared wavelengths

• US 20080221463A1
• Filed: 03/09/2007
• Published: 09/11/2008
• Est. Priority Date: 03/09/2007
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Nellcor Puritan Bennett LLC (Medtronic Plc)
• Inventors: Baker, Clark R.
• Granted Patent: US 8,109,882 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 5/6814 Head

Abstract

Methods and systems for detecting venous pulsation are provided. In accordance with an exemplary embodiment of the present technique, there is provided a method for detecting venous pulsation, including acquiring a first signal corresponding to absorption at a first near-infrared wavelength, acquiring a second signal corresponding to absorption at a second near-infrared wavelength, deriving an offset metric from the first and second signals, and detecting the presence of venous pulsation based on the offset metric. The method further includes correcting calculations of physiological parameters such as, for example, blood oxygen saturation, when venous pulsation is detected.

Claims

1. A method for detecting venous pulsation, comprising:

acquiring a first signal corresponding to absorption at a first near-infrared wavelength;

acquiring a second signal corresponding to absorption at a second near-infrared wavelength;

deriving an offset metric from the first and second signals; and

detecting the presence of venous pulsation based on the offset metric.

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

3. The method of claim 1, comprising acquiring a third signal corresponding to absorption at a third wavelength and calculating a physiological parameter based on the second and third signals.

4. The method of claim 3, comprising correcting an error in the calculation of the physiological parameter based on the offset metric.

5. The method of claim 3, wherein the second near-infrared wavelength comprises a wavelength of about 900 nm and wherein the third wavelength comprises a wavelength of about 660 nm.

6. The method of claim 1, wherein the first near-infrared wavelength comprises a wavelength where hemoglobin has a lower absorption than at the second near-infrared wavelength.

7. The method of claim 1, wherein the first near-infrared wavelength comprises a wavelength from 1,050 to 1,350 nm.

8. The method of claim 1, wherein the first near-infrared wavelength comprises a wavelength from 1,050 to 1,160 nm.

9. The method of claim 1, wherein deriving the offset metric from at least the first and second signals comprises calculating a ratio-of-ratios of the first signal to the second signal.

10. The method of claim 9, wherein detecting the presence of venous pulsation comprises comparing at least one of the ratio-of-ratios or a change in the ratio-of-ratios over time to a threshold value.

11. The method of claim 10, wherein the threshold value comprises at least one of a fixed value or a value based on a plurality of historic ratios-of-ratios.

12. A device for detecting venous pulsation, comprising:

a monitor configured to;

acquire a first signal corresponding to absorption at a first near-infrared wavelength and a second signal corresponding to absorption at a second near-infrared wavelength;

derive an offset metric from the first and second signals; and

detect the presence of venous pulsation based on the offset metric.

13. The device of claim 12, wherein the monitor is configured to provide a notification of the presence of venous pulsation when detected.

14. The device of claim 12, wherein the monitor is configured to acquire a third signal corresponding to absorption at a third wavelength and to calculate a physiological parameter based on the second and third signals.

15. The device of claim 14, wherein the monitor is configured to correct an error in the calculation of the physiological parameter based on the offset metric.

16. The device of claim 12, wherein the monitor is configured to derive the offset metric by calculating a ratio-of-ratios of the first signal to the second signal.

17. The device of claim 16, wherein the monitor is configured to detect the presence of venous pulsation by comparing at least one of the ratio-of-ratios or a change in the ratio-of-ratios over time to a threshold value.

18. A system for detecting venous pulsation, comprising:

a sensor configured to;

emit light at three or more wavelengths into a patient'"'"'s tissue; and

detect absorption of the light; and

a monitor configured to;

acquire a first signal corresponding to absorption at a first near-infrared wavelength and a second signal corresponding to absorption at a second near-infrared wavelength;

derive an offset metric from the first and second signals; and

detect the presence of venous pulsation based on the offset metric.

19. The system of claim 18, wherein the first near-infrared wavelength comprises a wavelength where hemoglobin has a lower absorption than at the second near-infrared wavelength.

20. The device of claim 18, wherein the three or more wavelengths comprise about 660 nm, about 900 nm, and about 1,126 nm.

21. The device of claim 18, wherein the monitor is configured to provide a notification of the presence of venous pulsation when detected.

22. The device of claim 18, wherein the monitor is configured to acquire a third signal corresponding to absorption at a red wavelength and to calculate a physiological parameter based on the second and third signals.

23. The device of claim 22, wherein the monitor is configured to correct an error in the calculation of the physiological parameter based on the offset metric.

24. The device of claim 18, wherein the monitor is configured to derive the offset metric by calculating a ratio-of-ratios of the first signal to the second signal.

25. The device of claim 24, wherein the monitor is configured to detect the presence of venous pulsation by comparing at least one of the ratio-of-ratios or a change in the ratio-of-ratios over time to a threshold value.

26. A method of manufacturing a device for detecting venous pulsation, comprising:

providing a monitor configured to;

acquire a first signal corresponding to absorption at a first near-infrared wavelength and a second signal corresponding to absorption at a second near-infrared wavelength;

derive an offset metric from the first and second signals; and

detect the presence of venous pulsation based on the offset metric.