Sensor identification method and system

• US 20070208236A1
• Filed: 12/22/2006
• Published: 09/06/2007
• Est. Priority Date: 01/31/2002
• Status: Active Grant

• Current Assignee: Datex-Ohmeda Incorporated (GE Healthcare Technologies, Inc.)
• Original Assignee: Datex-Ohmeda Incorporated (GE Healthcare Technologies, Inc.)
• Inventors: Hicks, Christopher
• Granted Patent: US 7,841,985 B2
• Time in Patent Office: Days
• US Class Current: 600/310
• CPC Class Codes: A61B 2562/085 combined with means for recording calibration data
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence

Abstract

An inventive method and system are provided for identifying a compatible photoplethysmographic sensor when interconnected to a given photoplethysmographic monitor. The method and system may further provide for the identification of which of a plurality of compatible sensors is interconnected to allow for selective calibration of the photoplethysmographic monitor. In this regard, the system and method may entail provision of a predetermined drive or test signal to a light source and/or identification element (i.e., sensor elements) of a photoplethysmographic sensor, and the obtainment of a corresponding output signal for use in sensor identification. In one approach, an output signal is obtained from at least one of three sensor elements each of which is interconnected between a different pair of sensor terminals which is a unique combination of two of four sensor terminals on the sensor. In this regard, individual circuits may be formed through each sensor element allowing for enhanced flexibility in signal application.

Claims

1. A method using a photoplethysmographic system, comprising:

releasably interconnecting a photoplethysmographic sensor to a photoplethysmographic monitor,

wherein a first pair of terminals on said sensor is connected for receiving first drive signals from said monitor for illuminating a first light source coupled between said first pair of terminals,

wherein a second pair of terminals on said sensor is connected for receiving second drive signals from said monitor for illuminating a second light source coupled between said second pair of terminals,

wherein a third pair of terminals on said sensor is connected for receiving an interrogation signal from said monitor for application across an identification element coupled between said third pair of terminals; and

wherein said first, second, and third connections each utilize a unique combination of terminals and wherein each said first, second, and third terminal pairs share at least one terminal with another of said first, second, and third terminal pairs;

applying a first interrogation signal to a terminal shared by two of said pairs of terminals to obtain a first output signal across one of said two pairs of sensor terminals;

applying a second interrogation signal across the other of said two pairs of sensor terminals to obtain a second output signal at said shared terminal; and

utilizing at least one of said first and second output signals to identify said sensor.

2. The method of claim 1, wherein at least one of said applying steps comprise applying an electrical signal to one terminal of said third pair of terminals to obtain at least one output signal across said third pair of terminals.

3. The method of claim 2, wherein said identification element is a diode.

4. The method of claim 3, wherein said output comprises a minimal and predeterminable voltage drop across said diode.

5. The method of claim 3, wherein said applying step further comprises;

applying a first electrical signal to obtain a first output signal from said diode; and

applying a second electrical signal to obtain a second output signal from said diode.

6. The method of claim 5, wherein said first and second electrical signals have different magnitudes.

7. The method of claim 6, wherein said first and second electrical signals have first and second current levels.

8. The method of claim 7, wherein said first and second current level are selected to produce first and second minimal and predeterminable voltage drops across said diode.

9. The method of claim 8, wherein said first and second voltage drops are substantially equal.

10. The method of claim 7, wherein said first and second electrical signals have a positive polarity and a negative polarity, respectively, as applied to said identification element.

11. The method of claim 1, further comprising:

upon obtaining at least one of said first and second output signals, disabling said third pair of terminals on said sensor.

12. The method of claim 1, further comprising:

applying an interrogation signal across at least one of said first and second pairs of terminals to obtain an additional output signal from at least one of said first and second light sources.

13. The method of claim 1, further comprising:

establishing a connection with a fourth pair terminals on said sensor operable to complete a circuit monitored by said monitor to identify sensor interconnection.

14. The method of claim 13, further comprising:

applying an electrical signal to one terminal of said fourth pair of terminals to obtain an interconnection output signal at the other terminal of said fourth pair of terminals

15. The method of claim 14, further comprising:

upon identifying said interconnection output signal, performing said applying steps.

16. The method of claim 14, wherein said interconnection output signal is utilized procure sensor information.

17. The method of claim 1, upon identifying said sensor, further comprising the step of:

applying predetermined drive signals to one terminal of at least one of said first and second terminal pairs on said sensor for controllably illuminating at least one of said first and second light sources.

18. The method of claim 17, wherein said at least one of said first and second light sources illuminates patient tissue-under-test.

19. The method of claim 18, further comprising:

establishing a connection with a fifth pair of terminals on said sensor having a light detector coupled there between; and

applying a detector drive signal to one terminal of said fifth pair of terminals to obtain a detector output signal at the other terminal of said third pair of terminals, wherein said detector output signal is indicative of light absorption of said tissue-under-test.

20. The method of claim 15, wherein said detector output signal is utilized for at least one of:

determining a blood analyte concentration value; and

determining at least one physiological parameter.

21. The method of claim 20, wherein said blood analyte concentration value comprises a blood oxygen value.

22. The method of claim 20, wherein said physiological parameter comprises a heart rate.

23. The method of claim 1, wherein releasably interconnecting further comprises:

interconnecting each terminal on said sensor to said monitor via a dedicated electrical pathway.

24. The method of claim 23, wherein four dedicated electrical pathways interconnect said first, second and third pairs of terminals on said sensor to said monitor.

25. The method of claim 1, further comprising:

comparing said output signal to a predetermined range of values to select information for use in calibrating said monitor.

26. The method of claim 25, wherein when said output signal is outside said predetermined range, said method further comprising at least one of:

providing an output to a user indicating that the sensor is not compatible with said monitor; and

disabling said monitor for use with said interconnected sensor.

27. The method of claim 25, wherein when said output signal is within said predetermined range, said method further comprising:

utilizing said output signal to select one of a plurality of calibration values for use in photoplethysmographic monitoring.