Sensor system with memory and method of using same

• US 20060167351A1
• Filed: 01/21/2005
• Published: 07/27/2006
• Est. Priority Date: 01/21/2005
• Status: Active Grant

• Current Assignee: Nonin Medical Incorporated
• Original Assignee: Nonin Medical Incorporated
• Inventors: Johnson, Timothy L., Isaacson, Philip O., Crackel, Joe Raymond
• Granted Patent: US 7,392,074 B2
• Time in Patent Office: Days
• US Class Current: 600/323
• CPC Class Codes: A61B 2562/085 combined with means for recording calibration data
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes

Abstract

A method of using an oximeter sensor assembly including the steps of detecting light from a light emitting element and storing digital data in a memory associated with the sensor assembly. The stored digital data includes coefficients for use by an oximeter monitor coupled to the sensor assembly to calculate data from the detected light, wherein the coefficients represent a combination of different sensor-specific characteristics, application-specific characteristics, and patient-specific characteristics. Control means including means for processing received information signals in accordance with the equation in response to received coefficients to determine blood oxygen levels is provided.

Claims

1. A method of using an oximeter sensor assembly, the method comprising:

emitting light from a light emitting element of a sensor assembly;

detecting light from the light emitting element using a light detecting element; and

storing digital data in a memory in the sensor assembly, said digital data including coefficients for use by an oximeter monitor coupled to the sensor assembly to calculate data from the detected light, wherein the coefficients represent a combination of different sensor-specific characteristics, application-specific characteristics, and patient-specific characteristics.

2. The method of claim 1 wherein the different sensor-specific characteristics include one or more of:

light emitting element characteristics, light detecting element characteristics, sensor type, sensor pressure, sensor color and sensor materials of construction.

3. The method of claim 1 wherein the different application-specific characteristics include one or more of:

location of sensor upon the patient, alignment of the sensor relative to the patient, sensor displacement during use, sensor temperature during use, and the effects from external light sources.

4. The method of claim 1 wherein the different patient-specific characteristics include one or more of:

age, gender, medical conditions of patient, skin color, and patient species information.

5. A sensor assembly used in an oximeter system for monitoring oxygen level in blood of a patient, the sensor assembly comprising;

at least one light emitting element configured to transmit light energy through tissue carrying the blood;

at least one photodetector configured to detect light energy; and

a memory element configured to store at least two coefficients for use by a monitor in calculating blood oxygen level, said at least two coefficients being communicated to the monitor, and each of said at least two coefficients representing a combination of different sensor-specific characteristics, application-specific characteristics, and patient-specific characteristics.

6. The sensor of claim 5 wherein the different sensor-specific characteristics include one or more of:

light emitting element characteristics, light detecting element characteristics, sensor pressure, sensor type, sensor color and sensor materials of construction.

7. The sensor of claim 5 wherein the different application-specific characteristics include one or more of:

location of sensor upon the patient, alignment of the sensor relative to the patient, sensor displacement during use, sensor temperature during use, and, and the effects of external light sources.

8. The sensor of claim 5 wherein the different patient-specific characteristics include one or more of:

age, gender, medical conditions of patient, skin color, and patient species information.

9. The sensor of claim 5 wherein the memory element is further configured to store at least one equation for use by the monitor in calculating blood oxygen level, said equation being communicated to the monitor for subsequent use to determine blood oxygen level.

10. A physiologic signal system comprising:

a light emitting element on a sensor;

a light detecting element on the sensor;

a memory for storing digital data on the sensor, said digital data being coefficients used to determine physiologic information based upon signals received from the light detecting element, said coefficients being derived as a combination of different sensor-specific characteristics, application-specific characteristics, and patient-specific characteristic; and

a monitor which receives light signals from the light detecting element and the coefficients from the sensor and which computes a physiologic measurement based upon the light signals and the coefficients.

11. The physiologic signal system of claim 10 wherein the memory also stores equation information which is communicated to the monitor prior to computation of the physiologic measurement.

12. The physiologic signal system of claim 10 wherein the sensor-specific characteristics include one or more of:

light emitting element characteristics, light detecting element characteristics, sensor pressure, sensor type, sensor color and sensor materials of construction.

13. The physiologic signal system of claim 10 wherein the different application-specific characteristics include one or more of:

location of sensor upon the patient, alignment of the sensor relative to the patient, sensor displacement during use, sensor temperature during use, and the effects from external light sources.

14. The physiologic signal system of claim 10 wherein the different patient-specific characteristics include one or more of:

age, gender, medical conditions of patient, skin color and patient species information.

15. A method of using an oximeter sensor system, the method comprising:

emitting light from a light emitting element on a sensor;

detecting light from the light emitting element using a light detecting element; and

storing digital data in a memory on the sensor, said digital data including coefficients for use by an oximeter monitor coupled to the oximeter sensor to calculate data from the detected light, wherein the coefficients represent a combination of different sensor-specific characteristics, application-specific characteristics, and patient-specific characteristics;

storing equation information in the memory; and

communicating the coefficients and the equation information to the monitor during sensor use; and

computing a blood oxygen level using the coefficients and equation information from the sensor.

16. The method of claim 15 wherein the different sensor-specific characteristics include one or more of:

light emitting element characteristics, light detecting element characteristics, sensor pressure, sensor type, sensor color and sensor materials of construction.

17. The method of claim 15 wherein the different application-specific characteristics include one or more of:

location of sensor upon the patient, alignment of the sensor relative to the patient, sensor displacement during use, sensor temperature during use, and, and the effects from external light sources.

18. The method of claim 15 wherein the different patient-specific characteristics include one or more of:

age, gender, medical conditions of patient, skin color, and patient species information

19. A physiologic signal system comprising:

a light emitting element on a sensor;

a light detecting element on the sensor;

a memory for storing information on the sensor, said information including coefficients used to determine physiologic information based upon signals received from the light detecting element, said coefficients being derived as a combination of different sensor-specific characteristics, application-specific characteristics, and patient-specific characteristic, said information also including an equation for use to compute a physiologic measurement; and

a monitor which receives light signals from the light detecting element and the coefficients and equation information from the sensor and which computes the physiologic measurement based upon the light signals, the coefficients and the equation information.

20. The physiologic signal system of claim 19 wherein the memory also stores equation information which is communicated to the monitor prior to computation of the physiologic measurement.

21. The physiologic signal system of claim 19 wherein the sensor-specific characteristics include one or more of:

light emitting element characteristics, light detecting element characteristics, sensor pressure, sensor type, sensor color and sensor materials of construction.

22. The physiologic signal system of claim 19 wherein the different application-specific characteristics include one or more of:

location of sensor upon the patient, alignment of the sensor relative to the patient, sensor displacement during use, sensor temperature during use, and the effects from external light sources.

23. The physiologic signal system of claim 19 wherein the different patient-specific characteristics include one or more of:

age, gender, medical conditions of patient, skin color and patient species information.

24. A physiologic signal system comprising:

a light emitting element on a sensor;

a light detecting element on the sensor;

a memory for storing information on the sensor, said information including coefficients used to determine physiologic measurements based upon light signals received from the light detecting element, said coefficients being derived as a combination of different sensor-specific characteristics, application-specific characteristics, and patient-specific characteristic, said information also including an equation for use to compute a physiologic parameter; and

a sensor processor which receives a preprocessed signal derived from an electrical signal from the light detecting element and uses the coefficients and equation information from the sensor to compute the physiologic measurement based upon the preprocessed signals, the coefficients and the equation information.

25. The physiologic signal system of claim 24 wherein the preprocessed signal includes information relating to an amplitude of a detected light signal.

26. The physiologic signal system of claim 25 wherein the preprocessed signal includes a red light amplitude and an infrared light amplitude.

27. The physiologic signal system of claim 25 wherein the preprocessed signal includes time derivatives of a received red light signal or infrared light signal or both.

28. The physiologic signal system of claim 24 wherein the physiologic measurements are blood oxygen levels.

29. A method for operating an oximeter system, the method comprising:

emitting light from a light emitting element in an oximeter sensor;

detecting light from the light emitting element using a photodetector in the sensor to define a light signal;

storing encoded data in a memory in the sensor, the encoded data including coefficients for use in an equation, said coefficients being derived by a plurality of different patient-specific characteristics, application-specific characteristics, and patient specific characteristics;

receiving said the encoded data from the memory; and

calculating blood oxygen levels utilizing the encoded data, the light signal and a blood oxygen saturation equation.

30. The method of claim 29 wherein the blood oxygen saturation equation is stored in an oximeter monitor and the oximeter monitor receives the encoded data and the light signal and calculates a value for blood oxygen saturation.

31. The method of claim 29 wherein the step of calculating blood oxygen level is at least partially performed by a processor on the sensor.

32. The method of claim 31 wherein information relating to blood oxygen levels is communicated to an oximeter monitor for visual display.

33. An oximeter system comprising:

a light emitter for illuminating a portion of a body;

means for supplying energy for said light emitter;

a light detector for detecting a portion of light emitted from the light emitter;

memory means on a portable sensor for storing a plurality of coefficients utilized in an equation to calculate blood oxygen levels, each of said plurality of coefficients defined as a combination of various different characteristics including application-specific characteristics, patient-specific characteristics, and patient specific characteristics; and

control means including means for processing received information signals in accordance with the equation in response to received coefficients to determine blood oxygen levels.

34. The oximeter system of claim 33 wherein the memory means also stores the equation.

35. The oximeter system of claim 33 wherein the control means is at least partially contained within a portable oximeter sensor which communicates with an external oximeter monitor.

36. The oximeter system of claim 33 wherein the control means is in an external oximeter monitor in communication with portable sensor.