Pulse oximeter and sensor optimized for low saturation

• US 20070156039A1
• Filed: 02/23/2007
• Published: 07/05/2007
• Est. Priority Date: 04/01/1994
• Status: Active Grant

• Current Assignee: Nellcor Puritan Bennett Incorporated (Medtronic Plc)
• Original Assignee: Nellcor Puritan Bennett Incorporated (Medtronic Plc)
• Inventors: Mannheimer, Paul, Nierlich, Steve, Ruskewicz, Stephen, Casciani, James
• Granted Patent: US 7,415,298 B2
• Time in Patent Office: Days
• US Class Current: 600/323
• CPC Class Codes: A61B 2562/0242 for varying or adjusting the optical path length in the tissue
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 takes precedence
• CPC Class Codes: A61B 5/1464 specially adapted for foetal tissue
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts

Abstract

A pulse oximeter sensor with a light source optimized for low oxygen saturation ranges and for maximizing the immunity to perturbation induced artifact. Preferably, a red and an infrared light source are used, with the red light source having a mean wavelength between 700-790 nm. The infrared light source can have a mean wavelength as in prior art devices used on patients with high saturation. The sensor of the present invention is further optimized by arranging the spacing between the light emitter and light detectors to minimize the sensitivity to perturbation induced artifact. The present invention optimizes the chosen wavelengths to achieve a closer matching of the absorption and scattering coefficient products for the red and IR light sources. This optimization gives robust readings in the presence of perturbation artifacts including force variations, tissue variations and variations in the oxygen saturation itself.

Claims

1. A method for measuring blood oxygen saturation comprising:

emitting light from at least one light source; and

detecting a plurality of light spectrums from the light with at least one detector subsequent to the light being scattered by tissue, the plurality of light spectrums including a first light spectrum having a wavelength range optimized for high oxygen saturation, a second light spectrum having a wavelength range optimized for low oxygen saturation, and a third light spectrum having a wavelength between 800 and 1000 nanometers.

2. The method of claim 1, wherein the wavelength range optimized for high oxygen saturation is from 650 to 670 nanometers.

3. The method of claim 2, wherein the third light spectrum wavelength is approximately 890 nanometers.

4. The method of claim 1, wherein the wavelength range optimized for low oxygen saturation is from 700 to 790 nanometers.

5. The method of claim 1, wherein the wavelength range optimized for low oxygen saturation is from 725 to 745 nanometers.

6. The method of claim 1, wherein the wavelength of the third light spectrum is from 880 to 940 nanometers.

7. The method of claim 1, wherein the third light spectrum wavelength is approximately 900 nanometers.

8. A method for measuring blood oxygen saturation comprising:

emitting light from at least one light source;

detecting a plurality of light spectrums from the light with at least one detector subsequent to the light being scattered by tissue, the plurality of light spectrums including a first light spectrum having a wavelength of approximately 660 nanometers, a second light spectrum having a wavelength of approximately 730 nanometers, and a third light spectrum having a wavelength of approximately 900 nanometers; and

selecting two of the first, second and third light spectrums for use in determining a calculated oxygen saturation value based on an estimated value of oxygen saturation.

9. A method for measuring blood oxygen saturation comprising:

emitting a first light including a first light spectrum having a wavelength range optimized for high oxygen saturation;

emitting a second light including a second light spectrum having a wavelength range optimized for low oxygen saturation;

emitting a third light including a third light spectrum having a wavelength between 800 and 1000 nanometers; and

detecting the first second and third lights with at least one detector subsequent to the light being scattered by tissue.

10. The method of claim 9, wherein the wavelength range optimized for high oxygen saturation is from 650 to 670 nanometers.

11. The method of claim 10, wherein the third light spectrum wavelength is approximately 890 nanometers.

12. The method of claim 9, wherein the wavelength range optimized for low oxygen saturation is from 700 to 790 nanometers.

13. The method of claim 9, wherein the wavelength range optimized for low oxygen saturation is from 725 to 745 nanometers.

14. The method of claim 9, wherein the wavelength of the third light spectrum is from 880 to 940 nanometers.

15. The method of claim 9, wherein the third light spectrum wavelength is approximately 900 nanometers.

16. A method for measuring blood oxygen saturation comprising:

emitting a first light having a wavelength of approximately 660 nanometers;

emitting a second light having a wavelength of approximately 730 nanometers;

emitting a third light having a wavelength of approximately 900 nanometers;

detecting the first light with a detector subsequent to the first light being scattered by tissue;

detecting the second light with the detector subsequent to the second light being scattered by the tissue;

detecting the third light with the detector subsequent to the third light being scattered by the tissue; and

selecting two of the first, second and third lights for use in determining a calculated oxygen saturation value based on an estimated value of oxygen saturation.