Motion compatible sensor for non-invasive optical blood analysis

• US 20050070775A1
• Filed: 11/16/2004
• Published: 03/31/2005
• Est. Priority Date: 10/10/1996
• Status: Active Grant

• Current Assignee: Nellcor Puritan Bennett Incorporated (Medtronic Plc)
• Original Assignee: Nellcor Puritan Bennett Incorporated (Medtronic Plc)
• Inventors: Mannheimer, Paul, Chin, Rodney, Flewelling, Ross
• Granted Patent: US 7,260,425 B2
• Time in Patent Office: Days
• US Class Current: 600/323
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/6826 Finger
• CPC Class Codes: A61B 5/6833 Adhesive patches
• CPC Class Codes: A61B 5/6838 Clamps or clips
• CPC Class Codes: A61B 5/7207 of noise induced by motion artifacts

Abstract

A non-invasive optical sensor which uses the motion signal to calculate the physiological characteristic being measured. For pulse oximetry, a least squares or a ratio-of-ratios technique can be applied to the motion signal itself. This is made possible by selecting a site on the patient where variations in motion produce signals of two wavelengths which are sufficiently correlated. In particular, it has been determined that a sensor placed on a nail, in particular a thumbnail, exhibits the characteristics of having the red and infrared signals correlated when used for pulse oximetry, and the resulting signals correlate to arterial oxygen saturation.

Claims

1. A pulse oximeter sensor comprising:

a light emitter;

a light detector;

processing circuitry in the sensor that calculates blood oxygen saturation values using signals received from the light detector; and

a transmitter in the sensor for wirelessly transmitting signals from the sensor to an oximeter monitor.

2. The pulse oximeter sensor defined in claim 1 wherein the sensor is a reflectance sensor.

3. The pulse oximeter sensor defined in claim 2 wherein the sensor is configured to attach to a patient'"'"'s digit over a nail, and wherein the light emitter and the light detector are configured to be mounted adjacent to the nail.

4. The pulse oximeter sensor defined in claim 3 wherein the pulse oximeter sensor is attached to a second transmissive pulse oximeter sensor that is configured to attach to the same patient digit, the second pulse oximeter sensor comprising a second light emitter and a second light detector.

5. The pulse oximeter sensor defined in claim 4 wherein the transmitter is in the second pulse oximeter sensor.

6. The pulse oximeter sensor defined in claim 4 wherein the transmitter is in the reflectance sensor.

7. The pulse oximeter sensor defined in claim 1 further comprising a display in the sensor for displaying the blood oxygen saturation values.

8. The pulse oximeter sensor defined in claim 7 wherein the light emitter, the light detector, the processing circuitry, the transmitter, and the display are all located in one housing.

9. The pulse oximeter sensor defined in claim 7 further comprising a button that allows switching between displaying a pulse and oxygen saturation.

10. A pulse oximeter sensor comprising:

a light emitter;

a light detector;

processing circuitry in the sensor that calculates blood oxygen saturation values and a pulse rate using signals received from the light detector;

a display in the sensor for displaying the blood oxygen saturation values and the pulse rate; and

a transmitter in the sensor for wirelessly transmitting signals from the sensor to an oximeter monitor.

11. The pulse oximeter sensor defined in claim 10 wherein the light emitter, the light detector, the processing circuitry, the transmitter, and the display are all located in one housing.

12. The pulse oximeter sensor defined in claim 10 wherein the sensor is a reflectance sensor.

13. The pulse oximeter sensor defined in claim 12 wherein the sensor is configured to attach to a patient'"'"'s digit over a nail, and wherein the light emitter and the light detector are configured to be mounted adjacent to the nail.

14. The pulse oximeter sensor defined in claim 13 wherein the pulse oximeter sensor is attached to a second transmissive pulse oximeter sensor that is configured to attach to the same patient digit, the second pulse oximeter sensor comprising a second light emitter and a second light detector.

15. The pulse oximeter sensor defined in claim 14 wherein the transmissive pulse oximeter sensor is attached to the reflectance pulse oximeter sensor via a flexible cable.

16. The pulse oximeter sensor defined in claim 15 wherein the transmitter is in the second transmissive pulse oximeter sensor.

17. The pulse oximeter sensor defined in claim 10 wherein the transmitter is in the reflectance sensor.

18. The pulse oximeter sensor defined in claim 10 further comprising a button that allows switching between displaying a pulse and oxygen saturation.