Multiple-code oximeter calibration element

• US 6,351,658 B1
• Filed: 09/28/1999
• Issued: 02/26/2002
• Est. Priority Date: 09/29/1998
• Status: Expired due to Term

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Mallinckrodt Incorporated (Mallinckrodt plc)
• Inventors: Bernstein, Michael J., Middleman, Lee, Fein, Michael E., Mannheimer, Paul D.
• Primary Examiner(s): Winakur, Eric F.
• Assistant Examiner(s): KREMER, MATTHEW J
• Application Number:
  US09/407,015
• Time in Patent Office: 882 Days
• Field of Search: 600/309-311, 600/322-324, 600/326, 600/328, 600/331, 600/476, 600/473, 356/39-42
• US Class Current: 600/331
• CPC Class Codes: A61B 2562/085 combined with means for recording calibration data
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes

Abstract

An encoding element which is backward compatible and will provide a single coded value to older analyzers in response to first signal, but will also provide a second coded value to a new analyzer or monitor. In one embodiment, both coded values are provided over the same first and second leads which are compatible with existing sensors. In another embodiment, a first voltage level produces a first current from the encoding element, while a second voltage level will produce the second coded value. In another embodiment, a first coded value is provided in response to a DC current from older analyzers. A second coded value is provided in response to a AC signal from newer analyzers. Yet another embodiment provides the coded value in the form of a resonant circuit in the AC driven mode. In another embodiment, the first coded value is provided over the same two leads after a period of time, with the second value being provided prior to that period of time passing.

Claims

1. An oximeter probe encoding apparatus, comprising:

first and second leads; and

an encoding device configured to produce a first code value at said first and second leads in response to a first signal applied by an oximeter monitor to said first and second leads, said encoding device being configured to produce a second code value at said first and second leads in response to a second signal applied by said oximeter monitor to said first and second leads.

2. The apparatus of claim 1 wherein at least three code values are produced.

3. The apparatus of claim 1 further comprising a third lead, wherein said second code value is produced in response to a control signal on said third lead.

4. The apparatus of claim 1 wherein said first code value is produced when said leads are driven with a first signal, and said second code value is produced when said leads are driven with a second signal.

5. The apparatus of claim 4 wherein said encoding device comprises a single encoding element.

6. The apparatus of claim 4 wherein said encoding device comprises:

a first encoding element, coupled to said first and second leads, configured to produce the first code value at said first and second leads when said first and second leads are driven with the first signal; and

a second encoding element, coupled to said first and second leads, configured to produce the second code value at said first and second leads, when said first and second leads are driven with the second signal.

7. The apparatus of claim 6 wherein said first encoding element is a passive element, and said second encoding element is an active element.

8. The apparatus of claim 6 wherein:

said first encoding element comprises a resistor; and

said second encoding element comprises a non-linear element.

9. The apparatus of claim 8 wherein said non-linear element comprises a first zener diode.

10. The apparatus of claim 9 wherein said zener diode is in series with said resistor.

11. The apparatus of claim 9 wherein said zener diode is in parallel with said resistor.

12. The apparatus of claim 9 wherein said second encoding element further comprises:

a second resistor in series with said zener diode.

13. The apparatus of claim 9 wherein said second element further comprises:

a second zener diode in series with said first mentioned zener diode, and having an opposite configuration to said first mentioned zener diode.

14. The apparatus of claim 13 wherein said second element further comprises a second resistor in series with said zener diodes.

15. The apparatus of claim 6 wherein:

said first encoding element comprises a first resistor; and

said second encoding element comprises a diode in parallel with said first resistor, and a second resistor in series with said diode.

16. The apparatus of claim 6 wherein:

said first element comprises a resistor; and

said second element comprises a current source coupled to said resistor.

17. The apparatus of claim 6 wherein said second encoding element comprises an AC impedance.

18. The apparatus of claim 6 wherein said first signal is a DC signal, and the second signal varies with time.

19. The apparatus of claim 18 wherein:

said first encoding element comprises a resistor; and

said second encoding clement comprises a capacitor in parallel with said resistor.

20. The apparatus of claim 19 further comprising a second resistor in series with said capacitor.

21. The apparatus of claim 19 wherein:

said first encoding element comprises a resistor; and

said second encoding element comprises an inductor.

22. The apparatus of claim 18 wherein:

said first encoding element comprises a resistor; and

said second encoding element comprises an arrangement of components forming a resonant circuit.

23. The apparatus of claim 18 wherein:

said first encoding element comprises a resistor; and

said second encoding element comprises a parallel arrangement of an inductor and a capacitor in series with said resistor.

24. The apparatus of claim 18 wherein:

said first encoding element comprises a resistor; and

said second encoding element comprises a series arrangement of an inductor and a capacitor in parallel with said resistor.

25. The apparatus of claim 18 wherein:

said encoding device comprises a single component with capacitance, inductance and resistance.

26. The apparatus of claim 4 wherein said first signal varies in a first manner with time and the second signal varies in a second, different manner with time.

27. The apparatus of claim 4 wherein said first and second code values are produced independent of a polarity of said first and second drive signals.

28. The apparatus of claim 27 wherein one of said first and second signals consists essentially of a constant current.

29. The apparatus of claim 1 wherein said encoding device comprises an integrated circuit configured to be activated to provide said second code value in response to the second signal.

30. The apparatus of claim 29 wherein at least three code values are produced.

31. The apparatus of claim 29 wherein said first and second code values are produced independent of a polarity of said first and second drive signals.

32. The apparatus of claim 1 wherein said encoding device is an integrated circuit, said first code value corresponds to a value from a resistor across said first and second leads, and said second code value is a digital code.

33. The apparatus of claim 1 wherein said apparatus is mounted at least partially in an adapter for an oximeter sensor.

34. The apparatus of claim 1 wherein said apparatus is mounted at least partially in a connecting cable of an oximeter sensor.

35. The apparatus of claim 1 wherein said apparatus is part of an oximeter sensor.

36. An oximeter probe encoding apparatus, comprising:

first and second leads;

a first encoding device comprising a resistor configured to produce a first code value in response to a first signal at a first time; and

a second encoding device configured to produce a second code value at a second time in response to said first signal, said second encoding device comprising a thermistor arranged to switch between first and second resistive states after being heated by being provided a current for a period of time.

37. An oximeter probe encoding apparatus, comprising:

first and second leads;

an encoding device configured to produce a first code value at said first and second leads in response to an oximeter monitor applying a first signal to said first and second leads at a first time; and

a capacitor coupled to said encoding device, wherein a charge on said capacitor changes in response to said oximeter monitor applying the first signal to said first and second leads, causing said encoding device to produce a second code value at said first and second leads at a second time.

38. An oximeter probe encoding apparatus, comprising:

first and second leads; and

a plurality of encoding devices configured to produce a plurality of code values at said first and second leads in response to signals applied by an oximeter monitor to said first and second leads.

39. An oximeter sensor encoding apparatus, comprising:

first and second leads;

a first encoding element coupled to said first and second leads, configured to produce a first code value at said first and second leads when said first and second leads are driven with a DC signal provided by an oximeter monitor; and

a second encoding element, coupled to said first encoding element, configured to produce a second code value at said first and second leads when said first and second leads are driven with an AC signal provided by said oximeter monitor;

wherein said first and second encoding elements are configured to produce the same first code value regardless of the polarity of said DC signal.

40. An oximeter sensor encoding apparatus, comprising:

first and second leads;

a first encoding element coupled to said first and second leads, configured to produce a first code value at said first and second leads when driven with a first voltage or current level applied by an oximeter monitor to said first and second leads at a first time; and

a second encoding element, coupled to said first encoding element, configured to produce a second code value at said first and second leads when driven with a second voltage or current level applied by said oximeter monitor to said first and second leads at a second time;

wherein said first and second encoding elements are configured to produce the same first code value regardless of the polarity of said first voltage or current level.

41. An oximeter sensor encoding apparatus, comprising:

first and second leads;

a first encoding device configured to provide a first encoded value across said first and second leads in response to a first signal applied by an oximeter monitor to said first and second leads; and

a second encoding device configured to provide a second encoded value across said first and second leads in response to a control signal on a third lead from said oximeter monitor.

42. An oximeter probe encoding apparatus, comprising:

a first lead;

a second lead;

a third lead;

an encoding device configured to produce a first code value at said first and second leads in response to a first signal applied by an oximeter monitor to said first and second leads, said encoding device being configured to produce a second code value at said first and second leads in response to a second signal from said oximeter monitor, and said encoding device being configured to produce a third code value at said first and second leads.

43. An oximeter probe encoding apparatus, comprising:

an LED driven by a drive current;

first and second leads;

a first encoding element coupled to said first and second leads, configured to produce a first code value at said first and second leads when driven with a first voltage or current level applied by an oximeter monitor to said first and second leads at a first time; and

a second encoding element configured to produce a second code value at said first and second leads when driven with a second voltage or current level provided by said LED drive current at a second time.