Method And Apparatus For Detecting And Analyzing Variations In A Physiologic Parameter

• US 20100292548A1
• Filed: 05/15/2009
• Published: 11/18/2010
• Est. Priority Date: 05/15/2009
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Nellcor Puritan Bennett LLC (Medtronic Plc)
• Inventors: Baker, Clark R. JR., Mannheimer, Paul D.
• Granted Patent: US 8,509,869 B2
• Time in Patent Office: Days
• US Class Current: 600/324
• CPC Class Codes: A61B 5/14551 for measuring blood gases

Abstract

The present disclosure is generally directed to identifying and/or analyzing high resolution variations in a measured physiologic parameter, such as blood oxygen saturation (SpO₂) measured using pulse oximetry. Present embodiments may include a system including a sensor comprising an emitter capable of emitting light at different wavelengths into a tissue bed, and a detector capable of detecting the light from the emitter after dispersion and/or reflection by the tissue bed. Further, the system may include a pulse oximeter capable of receiving signals from the sensor that are indicative of characteristics of the light detected by the detector, and utilizing the signals to estimate blood oxygen saturation values over time at a high resolution to facilitate detection of variations in the blood oxygen saturation values that are smaller in magnitude than an accuracy, display precision, and/or calibration of the blood oxygen saturation values.

Claims

1. A pulse oximetry system, comprising:

a sensor comprising;

an emitter capable of emitting light at different wavelengths into a tissue bed; and

a detector capable of detecting the light from the emitter after dispersion and/or reflection by the tissue bed; and

a pulse oximeter capable of;

receiving signals from the sensor that are indicative of characteristics of the light detected by the detector;

utilizing the signals to estimate blood oxygen saturation values over time at a high resolution;

detecting variations in the blood oxygen saturation values that are smaller in magnitude than an accuracy, display precision, and/or calibration of the blood oxygen saturation values; and

performing control and/or pattern detection functions based on the variations.

2. The pulse oximetry system of claim 1, wherein the pulse oximeter is capable of estimating the blood oxygen saturation values with a precision of 0.1%, 0.01% and/or 0.001%.

3. The pulse oximetry system of claim 1, comprising a controller capable of adjusting a delivery parameter based on a control algorithm and the variations in the blood oxygen saturation values.

4. The pulse oximetry system of claim 3, wherein the controller is capable of manipulating a composition and/or delivery amount of a gas mixture supplied to a patient based on the variations in the blood oxygen saturation values.

5. The pulse oximetry system of claim 4, wherein the controller is capable of controlling a physiologic parameter of a patient within a narrow range.

6. The pulse oximetry system of claim 1, wherein the pulse oximeter is capable of reporting changes in a value of partial pressure of oxygen in blood based on the detection of variations in the blood oxygen saturation values.

7. The pulse oximetry system of claim 1, wherein the emitter is capable of emitting light having a wavelength in a bounded range of 600-660 nm.

8. The pulse oximetry system of claim 7, wherein the emitter comprises at least two light emitting diodes, wherein one of the at least two light emitting diodes is capable of emitting light in the bounded range of 600-620 nm.

9. A method of performing pulse oximetry, comprising:

emitting light from an emitter component of a pulse oximeter sensor at first and second wavelengths useful for measuring oxygen saturation;

detecting the light with a detector component of the pulse oximeter sensor;

transmitting signals indicative of characteristics of the detected light to a pulse oximeter;

estimating blood oxygen saturation values over time at a high resolution based on the signals with the pulse oximeter;

detecting variations in the blood oxygen saturation values that are smaller in magnitude than an accuracy, display precision, and/or calibration of the blood oxygen saturation values; and

detecting a patient condition and/or controlling a physiologic parameter based on the variations.

10. The method of claim 9, wherein the first wavelength is near 660 nm.

11. The method of claim 9, wherein the first wavelength is within a range of 600-620 nm and the second wavelength is within a range of 800-940 nm

12. The method of claim 9, comprising controlling a partial pressure of oxygen in a patient'"'"'s blood based on the variations in the blood oxygen saturation values.

13. The method of claim 12, wherein controlling the partial pressure of oxygen comprises controlling delivery of oxygen to the patient based on the variations in the blood oxygen saturation values.

14. The method of claim 9, comprising identifying a pattern indicative of sleep apnea based on the variations in the blood oxygen saturation values.

15. The method of claim 9, comprising displaying the blood oxygen saturation values at the high resolution on a display screen.

16. A pulse oximeter sensor capable of facilitating detection of high precision changes in blood oxygen saturation estimates obtained via pulse oximetry, comprising:

a sensor body;

a plurality of emitters positioned within the sensor body, wherein each of the plurality of emitters is capable of emitting light at a different wavelength, and wherein at least one of the plurality of emitters is selected for sensitivity to small changes in blood oxygen saturation by emitting light within a bounded range of wavelengths;

a detector capable of detecting the light emitted by the plurality of emitters; and

a processor configured to calculate a value of blood oxygen saturation based on the detected light with a precision of 0.1, 0.01, and/or 0.001.

17. The pulse oximeter sensor of claim 16, wherein a one of the plurality of emitters is capable of emitting light having a wavelength in a bounded range of 600-620 nm.

18. The pulse oximeter sensor of claim 17, wherein a one of the plurality of emitters is capable of emitting light having a wavelength near 660 nm and another one of the plurality of emitters is capable of emitting light having a wavelength near 950 nm.

19. The pulse oximeter sensor of claim 17, wherein the plurality of emitters comprise an orange LED capable of emitting light having a wavelength in a bounded range of 600-620 nm, and an infrared LED capable of emitting light having a wavelength in a bounded range of 800-940 nm.

20. The pulse oximeter sensor of claim 17, wherein the plurality of emitters comprise an orange LED capable of emitting light having a wavelength in a bounded range of 600-620 nm, and a red LED capable of emitting light having a wavelength in a bounded range of 640-740 nm.