METHOD FOR DETECTION OF ABERRANT TISSUE SPECTRA

• US 20120323095A1
• Filed: 08/29/2012
• Published: 12/20/2012
• 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. Jr.
• Granted Patent: US 9,801,584 B2
• Time in Patent Office: Days
• US Class Current: 600/324
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal

Abstract

A method is provided for determining contact of a sensor with a patient'"'"'s tissue. The method comprises comparing the intensity of detected light at a first wavelength to a threshold, wherein the first wavelength is not used to determine a physiological characteristic of the patient, and determining if the sensor is in contact with the patient'"'"'s tissue based on the comparison. In addition, a method is provided for determining the amount of light shunting during operation of the sensor. The method comprises comparing the intensity of detected light at a first wavelength to a threshold, wherein the first wavelength is not used to determine a physiological characteristic of the patient, and determining the amount of light shunting based on the comparison.

Claims

1. A method for correcting light shunting, comprising:

emitting light at three or more wavelengths from at least one emitter of a sensor into a patient'"'"'s tissue, wherein the three or more wavelengths includes a first wavelength that is not used to determine a physiological characteristic of the patient;

detecting the light with at least one detector of the sensor;

comparing the intensity of the detected light at the first wavelength to a threshold; and

determining the amount of light shunting between the at least one emitter and the at least one detector based on the comparison.

2. The method of claim 1, comprising correcting the intensity of the detected light at one or more of a second wavelength or a third wavelength based on the amount of light shunting.

3. The method of claim 2, wherein correcting the intensity comprises subtracting the amount of light shunting from the intensity of the detected light at the second wavelength or the third wavelength.

4. The method of claim 2, comprising determining a physiological characteristic based upon the corrected intensity of the detected light at the second or third wavelengths.

5. The method of claim 1, wherein comparing the intensity comprises comparing a ratio of the intensity of the detected light at the first wavelength to a reference intensity of light at the first wavelength to the threshold.

6. The method of claim 1, wherein comparing the intensity comprises comparing a ratio of the intensity of the detected light at the first wavelength to a reference intensity of light at a different wavelength to the threshold.

7. The method of claim 1, wherein the first wavelength is primarily absorbed by water.

8. The method of claim 7, wherein the first wavelength of the detected light is between about 1200 nanometers to about 1600 nanometers.

9. The method of claim 1, wherein the sensor comprises a sensor configured to measure tissue hydration.

10. The method of claim 1, wherein the sensor comprises a pulse oximetry sensor.

11. The method of claim 1, determining if the sensor is in contact with the patient'"'"'s tissue based on the comparison.

12. A patient monitor, comprising:

a port configured to connect to a sensor;

a processor configured to receive signals from the port and to use the signals when executing an algorithm configured to compare an intensity of a first wavelength of detected light to a threshold, wherein the first wavelength is not used to determine a physiological characteristic of a patient, and wherein the processor is also configured to execute a second algorithm configured to determine an amount of light shunting between at least one emitter of the sensor and at least one detector of the sensor based on the comparison.

13. The patient monitor of claim 12, wherein the algorithm comparing the intensity is configured, when executed by the processor, to compare a ratio of the intensity of the first wavelength of the detected light to a reference intensity of light at the first wavelength to the threshold.

14. The patient monitor of claim 12, wherein the algorithm comparing the intensity is configured, when executed by the processor, to compare a ratio of the intensity of the first wavelength of the detected light to a reference intensity of light at a different wavelength to the threshold.

15. The patient monitor of claim 12, wherein the first wavelength is configured to be primarily absorbed by water.

16. The patient monitor of claim 12, wherein the first wavelength is configured to be primarily absorbed by myoglobin or hemoglobin.

17. The patient monitor of claim 12, wherein the processor is configured to execute a third algorithm to determine if the sensor is in contact with the patient'"'"'s tissue based on the comparison.

18. A sensor, comprising:

one or more light emitting components configured to emit light at three or more wavelengths;

one or more light detecting components configured to detect the light emitted by the one or more light emitting components, wherein at least one of the wavelengths is not used to determine a physiological characteristic but is used to determine an amount of light shunting between the one or more light emitting components and the one or more light detecting components based on a comparison between an intensity of detected light at the at least one wavelength and a threshold value;

an information encoding element that encodes the threshold value that corresponds with the at least one wavelength, wherein the threshold value, when provided to a monitor, permits the monitor to execute the comparison; and

a sensor body upon which the one or more light emitting components, the one or more light detecting components, and the information encoding element are disposed.

19. The sensor of claim 18, wherein the at least one wavelength is configured to be primarily absorbed by water.

20. The sensor of claim 18, wherein the at least one wavelength is configured to be primarily absorbed by myoglobin or hemoglobin.

21. A patient monitoring system, comprising:

a sensor comprising;

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

a detector configured to detect the light; and

a monitor configured to execute an algorithm configured to compare an intensity of a wavelength of detected light to a threshold, wherein the wavelength is not used to determine a physiological characteristic of the patient, and a second algorithm configured to determine an amount of light shunting between the emitter and the detector based on the comparison.

22. The patient monitoring system of claim 21, wherein the algorithm comparing the intensity is configured, when executed by the monitor, to compare a ratio of the intensity of the wavelength of the detected light a reference intensity of light at the wavelength to the threshold.

23. The patient monitoring system of claim 21, wherein the algorithm comparing the intensity is configured, when executed by the monitor, to compare a ratio of the intensity of the wavelength of the detected light to a reference intensity of light at a different wavelength to the threshold.