WAVELENGTH SWITCHING FOR PULSE OXIMETRY

• US 20120071739A1
• Filed: 09/22/2010
• Published: 03/22/2012
• Est. Priority Date: 09/22/2010
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Nellcor Puritan Bennett LLC (Medtronic Plc)
• Inventors: Chen, Bo, McKenna, Edward M., Li, Youzhi, Lisogurski, Daniel
• Granted Patent: US 8,649,838 B2
• Time in Patent Office: Days
• US Class Current: 600/323
• CPC Class Codes: A61B 2560/02 Operational features
• 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 5/02427 Details of sensor
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor

Abstract

The present disclosure describes techniques that may provide more accurate estimates of arterial oxygen saturation using pulse oximetry by switching between a wavelength spectrum of at least a first and a second light source so that the arterial oxygen saturation estimates at low (e.g., in the range below 75%), medium (e.g., greater than or equal to 75% and less than or equal to 84%), and high (e.g., greater than 84% range) arterial oxygen saturation values are more accurately calculated. In one embodiment, light emitted from a near 660 nm and a near 900 nm emitter pair may be used when the arterial oxygen saturation range is high. In another embodiment, light emitted from a near 730 nm and a near 900 nm emitter pair may be used when the arterial oxygen saturation range is low. In yet another embodiment, light emitted from both a near 660 nm-900 nm emitter pair and light emitted from a near 730 nm-900 nm emitter pair may be used when the arterial oxygen saturation range is in the middle range. Priming techniques may also be used to reduce or eliminate start up delays of certain oximetry system components.

Claims

1. A sensor comprising:

a first emitter having a wavelength adapted to substantially optimize physiologic measurements in patients having high oxygen saturation levels; and

a second emitter having a wavelength adapted to substantially optimize physiologic measurements in patients having low oxygen saturation levels;

the first emitter and the second emitter being capable of being alternatively activated to substantially optimize physiologic measurements in patients having oxygen saturation levels in a transition region between the high oxygen saturation levels and the low oxygen saturation levels.

2. The sensor of claim 1, wherein the high and low oxygen saturation levels comprise arterial saturation levels, venous saturation levels, or a combination thereof.

3. The sensor of claim 1, wherein the high oxygen saturation level comprises a level of arterial oxygen saturation greater than 84%, or greater than 90%.

4. The sensor of claim 1, wherein the low oxygen saturation level comprises a level of arterial oxygen saturation less than 70%, or less than 76%.

5. The sensor of claim 1, wherein the transition region oxygen saturation level comprises a level of arterial oxygen saturation between 85% and 76%, or between 70% and 90%.

6. The sensor of claim 1, wherein the first emitter and the second emitter being capable of being alternatively activated to prime components of the sensor, or to prime components of a monitor communicatively coupled to the sensor, or to prime components of both the sensor and the monitor.

7. The sensor of claim 1, wherein the first emitter is configured to emit light at a wavelength of between about 620 nanometers and about 700 nanometers.

8. The sensor of claim 1, wherein the second emitter is configured to emit light at a wavelength of between about 690 nanometers and about 770 nanometers.

9. The sensor of claim 1, comprising a third emitter, wherein a third emitter is configured to emit light at a wavelength of between about 860 nanometers and about 940 nanometers.

10. The sensor of claim 1, wherein the first emitter and the second emitter are both activated to calculate an oxygen saturation measurement.

11. The sensor of claim 1, wherein the sensor is configured for a reflectance mode of operation or a transmittance mode of operation.

12. A method of sensing physiologic parameters of a patient, the method comprising:

if the patient'"'"'s arterial oxygen saturation level is in a high range, driving only a first set of emitters on a sensor adapted to substantially optimize physiologic measurements in patients having high arterial oxygen saturation levels;

if the patient'"'"'s arterial oxygen saturation level is in a low range, driving only a second set of emitters on the sensor adapted to substantially optimize physiologic measurements in patients having low arterial oxygen saturation levels; and

if the patient'"'"'s arterial oxygen saturation level is in a transition range between the high range and the low range, driving the first and second sets of emitters on the sensor.

13. The method of claim 12, wherein the high range comprises a range of arterial oxygen saturation greater than 84%.

14. The method of claim 12, wherein the transition range comprises a range of arterial oxygen saturation between 85% and 76%.

15. The method of claim 12, wherein the high range comprises a range of arterial oxygen saturation greater than 89%, and wherein the low range comprises a range of arterial oxygen saturation less than 71%.

16. The method of claim 12, wherein the transition range comprises a range of arterial oxygen saturation between 90% and 70%.

17. The method of claim 12, comprising determining a final SpO₂ value by using a weight factor table, using an equation, or a combination thereof.

18. The method of claim 12, comprising driving the first and the second set of emitters after a system start.

19. The method of claim 12, comprising driving the first or the second set of emitters after a system start.

20. A system, comprising:

a monitor; and

a sensor comprising;

a first emitter having a wavelength adapted to substantially optimize physiologic measurements in patients having high arterial oxygen saturation levels; and

a second emitter having a wavelength adapted to substantially optimize physiologic measurements in patients having low arterial oxygen saturation levels;

the first emitter and the second emitter being capable of being alternatively driven by the monitor to substantially optimize physiologic measurements in patients having arterial oxygen saturation levels in a transition region between the high arterial oxygen saturation levels and the low arterial oxygen saturation levels.

21. The system of claim 20, wherein a first set of emitters are driven by the monitor so as to substantially optimize physiologic measurements in patients having high arterial oxygen saturation levels;

a second set of emitters are driven by the monitor so as to substantially optimize physiologic measurements in patients having low arterial oxygen saturation levels; and

a first and second sets of emitters are driven by the monitor so as to substantially optimize physiologic measurements in patients having an arterial oxygen saturation level in a transition region between the high levels and the low levels.

22. The system of claim 21, wherein the monitor is configured to demodulate the signals detected from a first and a second emitter pairs.

23. The system of claim 21, wherein the first emitter and the second emitter being capable of being alternatively driven by the monitor so as to prime components of the sensor, monitor, or combination thereof.