Oxygen monitoring apparatus

• US 6,632,402 B2
• Filed: 01/24/2001
• Issued: 10/14/2003
• Est. Priority Date: 01/24/2001
• Status: Expired due to Fees

• Current Assignee: RIC INVESTMENTS LLC (Koninklijke Philips N.V.)
• Original Assignee: NTC Technology, Inc. (Dixtal Medical, Inc.)
• Inventors: Apperson, Jerry R., Blazewicz, Perry R., Mace, Leslie E.
• Primary Examiner(s): SNAY, JEFFREY R
• Application Number:
  US09/769,015
• Publication Number:
  US 20020098120A1
• Time in Patent Office: 993 Days
• Field of Search: 422/82.07, 422/82.08, 422/84, 422/91, 436/136, 436/138, 436/172, 436/165, 600/529, 600/532, 250/458.1, 250/459.1
• US Class Current: 422/84
• CPC Class Codes: G01N 2021/6432 Quenching
• CPC Class Codes: G01N 2021/7786 Fluorescence
• CPC Class Codes: G01N 21/6408 with measurement of decay time, time resolved fluorescence
• CPC Class Codes: G01N 21/783 for analysing gases
• CPC Class Codes: Y10T 436/207497 Molecular oxygen
• CPC Class Codes: Y10T 436/209163 Dissolved or trace oxygen or oxygen content of a sealed environment

Abstract

Apparatus or systems which employ luminescence-quenching to produce a signal indicative of oxygen concentration. Components of such systems include: (1) an airway adapter, sampling cell, or the like having a casing and a sensor which is excited into luminescence with the luminescence decaying in a manner reflecting the concentration of oxygen in gases flowing through the airway adapter or other flow device and is in intimate contact with a window in the casing; (2) a transducer which has a light source for exciting a luminescable composition in the sensor into luminescence, a light sensitive detector for converting energy emitted from the luminescing composition as that the composition is quenched into an electrical signal indicative of oxygen concentration in the gases being monitored, and a casing which locates the light source and detector in close physical proximity to the window but on the side thereof opposite the sensor; and (3) subsystems for maintaining the sensor temperature constant and the temperature of the window above condensation temperature and for processing the signal generated by the light sensitive detector. Airway adapters, sampling cells, and transducers for such systems are also disclosed.

Claims

1. A sampling device of a respiratory gas sensor, comprising:

a housing;

a window formed through said housing;

a flow passage for receiving a sample, said flow passage being defined by said housing and said window;

a luminescable material positioned within said flow passage, proximate said window, and exposed through said window; and

a temperature communication element in contact with at least one of said luminescable material, a matrix or support structure for said luminescable material, and said window.

2. The sampling device of claim 1, wherein said luminescable material is carried upon a substrate positioned in contact with said window.

3. The sampling device of claim 2, wherein said substrate is porous.

4. The sampling device of claim 3, wherein said substrate comprises a membrane.

5. The sampling device of claim 2, further comprising:

a retention element adjacent said window.

6. The sampling device of claim 5, wherein said retention element comprises:

said window and an aperture formed in said housing and configured to receive said window.

7. The sampling device of claim 6, wherein said aperture receives at least an edge portion of said substrate and said window secures at least said edge portion within said aperture upon positioning of said window therein.

8. The sampling device of claim 5, further comprising:

a membrane for securing said luminescable material adjacent to said window, at least an edge portion of said membrane being secured by said retention element.

9. The sampling device of claim 1, wherein said luminescable material is capable of emitting at least one wavelength of electromagnetic radiation that, upon exposure of said luminescable material to at least one analyzed substance, is quenched at a rate related to a quantity of said at least one analyzed substance.

10. The sampling device of claim 9, wherein said at least one analyzed substance comprises oxygen.

11. The sampling device of claim 9, wherein said quantity comprises at least one of a concentration of said at least one analyzed substance and a partial pressure of said at least one analyzed substance in a mixture comprising at least one gaseous component.

12. The sampling device of claim 1, wherein said temperature communication element contacts at least a portion of said window.

13. The sampling device of claim 12, wherein said temperature communication element comprises an annular member in contact with an outer peripheral portion of said window.

14. The sampling device of claim 1, wherein said temperature communication element comprises a heating element.

15. The sampling device of claim 1, wherein said temperature communication element is configured to maintain at least said luminescable material at a substantially constant temperature.

16. The sampling device of claim 1, wherein said temperature communication element is configured to prevent moisture from collecting on said window.

17. The sampling device of claim 1, wherein said housing is configured to be positioned along the length of a breathing circuit.

18. The sampling device of claim 1, wherein said housing comprises a housing of a side stream sampling cell.

19. A respiratory gas sensor, comprising:

a sampling device, comprising;

a housing;

a window through said housing;

a flow passage for receiving a sample, said flow passage being defined by said housing and said window;

a luminescable material positioned within said flow passage and exposed through said window, luminescence of said luminescable material being quenchable upon exposure to at least one analyzable substance; and

a temperature communication element in thermal communication with at least one of said window and said luminescable material; and

a transducer configured for assembly with at least a portion of said sampling device, said transducer comprising;

a housing;

a source of at least one wavelength of electromagnetic radiation within said housing; and

a detector within said housing, said source and said detector being oriented toward said luminescable material upon placement of said sampling device and said transducer in an assembled relationship.

20. The respiratory gas sensor of claim 19, wherein said luminescable material is carried upon a substrate positioned in contact with said window.

21. The respiratory gas sensor of claim 19, wherein said luminescable material is capable of emitting at least one wavelength of electromagnetic radiation that, upon exposure of said luminescable material to at least one analyzed substance, is quenched at a rate related to a quantity of said at least one analyzed substance.

22. The respiratory gas sensor of claim 19, wherein said at least one analyzed substance comprises oxygen.

23. The respiratory gas sensor of claim 21, wherein said quantity comprises at least one of a concentration of said at least one analyzed substance and a partial pressure of said at least one analyzed substance in a mixture comprising at least one gaseous component.

24. The respiratory gas sensor of claim 19, wherein said temperature communication element contacts at least a portion of said window.

25. The respiratory gas sensor of claim 24, wherein said temperature communication element comprises an annular member in contact with an outer peripheral portion of said window.

26. The respiratory gas sensor of claim 19, wherein said temperature communication element is configured to maintain at least said luminescable material at a substantially constant temperature.

27. The respiratory gas sensor of claim 19, wherein said temperature communication element is configured to prevent moisture from collecting on said window.

28. The respiratory gas sensor of claim 19, wherein said transducer further comprises:

a temperature control element that communicates with said temperature communication element upon placement of said sampling device and said transducer in said assembled relationship.

29. The respiratory gas sensor of claim 19, wherein said temperature control element comprises a heating element.

30. The respiratory gas sensor of claim 19, wherein at least one of said sampling device and said transducer comprises an interconnection element.

31. The respiratory gas sensor of claim 30, wherein said interconnection element is configured to detachably couple said sampling device and said transducer to one another.

32. The respiratory gas sensor of claim 30, wherein said interconnection element is configured to prevent misalignment of said sampling device and said transducer relative to one another.

33. The respiratory gas sensor of claim 19, wherein at least said detector communicates signals to a processor that, based upon variations in said signal, determines a quantity of at least one analyzed substance to which said luminescable material is exposed.

34. The respiratory gas sensor of claim 19, wherein said housing of said sampling device is configured to be positioned along the length of a breathing circuit.

35. The respiratory gas sensor of claim 19, wherein said housing of said sampling device comprises a housing of a side stream sampling cell.

36. The respiratory gas sensor of claim 35, further comprising:

a sampling tube that communicates gases from said breathing circuit to said sampling device.

37. The respiratory gas sensor of claim 36, further comprising:

a pump in communication with said sampling tube to facilitate the flow of gas into said sampling device.

38. The respiratory gas sensor of claim 19, further comprising:

a pressure measurement component.

39. The respiratory gas sensor of claim 38, wherein said pressure measurement component comprises an absolute pressure transducer.

40. The respiratory gas sensor of claim 39, wherein said pressure transducer is located to communicate with at least said flow passage.

41. The respiratory gas sensor of claim 40, further comprising:

a valve configured to communicate a baseline pressure to said flow passage.

42. The respiratory gas sensor of claim 38, wherein said pressure measurement component comprises a differential pressure transducer.

43. The respiratory gas sensor of claim 42, wherein said differential pressure transducer communicates with at least said flow passage and said baseline pressure.

44. The respiratory gas sensor of claim 38, wherein said pressure measurement component is at least partially contained within said housing of said transducer.

45. The respiratory gas sensor of claim 38, wherein said pressure measurement component communicates signals to a processor.

46. The respiratory gas sensor of claim 45, wherein said housing of said sampling device comprises a housing of a side stream sampling cell.

47. The respiratory gas sensor of claim 46, further comprising:

a pump in communication with said sampling tube to facilitate the flow of gas into said sampling device.

48. The respiratory gas sensor of claim 47, wherein said processor controls operation of said pump based on said signals received from said pressure measurement component.

49. A transducer of a respiratory gas sensor, comprising:

a transducer housing configured to be assembled with a sampling device housing of the respiratory gas sensor;

a source of at least one wavelength of electromagnetic radiation positioned within said transducer housing to direct said at least one wavelength of electromagnetic radiation toward a window of said sampling device housing and a sensing film, proximate said window, upon assembly of said transducer housing with said sampling device housing;

a detector positioned within said transducer housing to receive at least one wavelength of electromagnetic radiation related to a quantity of an analyzed gas emitted through said window of said sampling device housing; and

a temperature communication element in contact with at least one of said sensing film, a matrix or support structure for said sensing film and said window upon assembly of said transducer housing with said sampling device housing, said temperature communication element being configured to effect at least one of;

monitoring the temperature of at least one of said window and said sensing film, and

controlling the temperature of at least one of said window and said sensing film;

wherein said sensing film is comprised of a luminescable material, and wherein luminescence of said luminescable material is quenchable upon exposure to at least one analyzable substance.

50. The transducer of claim 49, further comprising:

an interconnection element for removably securing the transducer to a complementary portion of said sampling device housing.

51. The transducer of claim 50, wherein said interconnection element is configured to prevent improper assembly of the transducer with said sampling device housing.