Device and method for measuring lung performance

• US 6,447,459 B1
• Filed: 04/07/2000
• Issued: 09/10/2002
• Est. Priority Date: 04/07/2000
• Status: Expired due to Term

• Current Assignee: KOKO It LLC
• Original Assignee: PDS Healthcare Products Incorporated
• Inventors: Larom, Dov
• Primary Examiner(s): Nasser, Robert L.
• Assistant Examiner(s): Mallari, Patricia C.
• Application Number:
  US09/545,624
• Time in Patent Office: 886 Days
• Field of Search: 600/538, 600/529
• US Class Current: 600/538
• CPC Class Codes: A61B 5/0823 Detecting or evaluating cough events
• CPC Class Codes: A61B 5/0876 using means deflected by the fluid stream, e.g. flaps
• CPC Class Codes: A61B 5/743 Displaying an image simultaneously with additional graphical information, e.g. symbols, charts, function plots
• CPC Class Codes: A61B 5/7475 User input or interface means, e.g. keyboard, pointing device, joystick

Abstract

The flow measurement device of the present invention incorporates numerous novel features. For example, the device includes a displacement measuring device to measure the position of a movable plate member, a self-oscillation dampener to dampen oscillations of the plate member, one or more stiffening members engaging or incorporated into the plate member to increase the resonant frequency of the plate member and reduce flutter, and a conduit providing for differing directions of air flow at different points along its length to eliminate the effects of gravity on flow measurements.

Claims

1. A device for measuring respiratory air flow, comprising:

(a) a conduit having an inlet for exhaled air and an outlet for the exhaled air;

(b) a sensing member movably disposed in the conduit between the inlet and at least a portion of the outlet, the sensing member at least partially blocking at least a portion of the conduit and moving in response to the passage of the exhaled air through the conduit; and

(c) a self-oscillation dampener movably engaging the sensing member, wherein the self-oscillation dampener dampens an amplitude of oscillations of the sensing member in response to the exhaled air contacting the sensing member.

2. The device of claim 1, wherein the self-oscillation dampener frictionally resists movement of the sensing member.

3. The device of claim 1, wherein the self-oscillation dampener is inclined at a contact angle relative to the sensing member and the angle is 75°

or less.

4. The device of claim 1, wherein the sensing member has a height and the self-oscillation dampener engages the sensing member at a point that is at a distance of at least about 25% and no more than about 95% of the height from a lower edge of the sensing member.

5. The device of claim 1, wherein the sensing member includes or engages one or more stiffening members to provide a desired natural frequency to the sensing member.

6. The device of claim 1, wherein the conduit redirects a direction of flow of the exhaled air such that at the inlet the direction of flow is substantially parallel to a surface of the sensing member and at the sensing member the direction of flow is substantially normal to the surface of the sensing member.

7. The device of claim 1, wherein the self-oscillation dampener has a length and the length ranges from about 10 to about 150% of the height of the sensing member.

8. The device of claim 1, further comprising a measuring device for measuring, as a function of time, at least one of a force applied to the sensing member by the exhaled air and a location of the sensing member, and wherein the measuring device is at least one of a strain gauge and a radiant energy emitter in communication with a radiant energy detector.

9. The device of claim 1, wherein a first end of the self-oscillation dampener movably engages the sensing member and a second end of the self-oscillation dampener fixedly engages a surface of the conduit.

10. A method for measuring respiratory air flow, comprising:

(a) exhaling air into an inlet of a conduit;

(b) moving a sensing member that is movably disposed in the conduit downstream of the inlet, the sensing member at least partially blocking the conduit and moving in response to the passage of the exhaled air through the conduit;

(c) resisting movement of the sensing member with a self-oscillation dampener to dampen amplitudes of oscillations of the sensing member; and

(d) measuring at least one of a force applied to the sensing member by the exhaled air and the location of the sensing member.

11. The method of claim 10, wherein the measuring step includes:

contacting the sensing member with a radiant beam; and

receiving a reflected radiant beam with a detector.

12. The method of claim 11, wherein the sensing member includes a bar code for encoding the reflected radiant beam.

13. The method of claim 10, wherein the sensing member includes one or more stiffening members to control a natural frequency of the sensing member.

14. The method of claim 10, wherein the measuring step includes:

measuring the location of the sensing member at a plurality of points in time and generating a plurality of location signals; and

processing the plurality of location signals to determine a desired air flow parameter.

15. A system for measuring respiratory air flow, comprising:

(a) an inlet of a conduit for receiving exhaled air;

(b) a plate member that is movably disposed in the conduit downstream of the inlet, the plate member at least partially blocking the conduit and moving in response to the passage of the exhaled air through the conduit;

(c) a self-oscillation dampener for resisting movement of the plate member to dampen amplitudes of oscillations of the plate member; and

(d) means for measuring at least one of a force applied to the plate member by the exhaled air and the location of the plate member.

16. The system of claim 15, wherein the self-oscillation dampener is inclined at an angle relative to the plate member and the angle is 75°

or less.

17. The system of claim 15, wherein the plate member has a height and the self-oscillation dampener engages the plate at a point that is at distance of at least about 25% and no more than about 95% of the height from a lower edge of the plate member.

18. The system of claim 15, wherein the plate member includes or engages one or more stiffening members to impart rigidity to the plate member.

19. The system of claim 15, wherein the conduit redirects a direction of flow of the exhaled air such that at the inlet the direction of flow is substantially parallel to a plane of the plate member and at the plate member the direction of flow is substantially normal to the plane of the plate member.

20. The system of claim 15, wherein the self-oscillation dampener has a length and the length ranges from about 10 to about 150% of the height of the plate member.

21. The system of claim 15, wherein the measuring means is at least one of a strain gauge and a radiant energy emitter in communication with a radiant energy detector.

22. The system of claim 15, wherein the self-oscillation dampener frictionally resists movement of the plate member.

23. A device for measuring respiratory air flow, comprising:

(a) a conduit having an inlet for exhaled air and an outlet for the exhaled air;

(b) a plate member movably disposed in the conduit between the inlet and outlet, the plate member at least partially blocking the conduit and moving in response to passage of the exhaled air through the conduit, wherein the plate member is perforated to maintain a resonant frequency of the plate member above a selected level, wherein the selected level is higher than a frequency of oscillations imparted to the plate member by the exhaled air; and

(c) an air flow measuring device for measuring the air flow through the conduit.

24. The device of claim 23, further comprising one or more stiffening members located at one or more peripheral edges of the plate member.

25. The device of claim 24, wherein the one or more stiffening members are located on a downstream surface of the plate member relative to the direction of exhaled air flow.

26. The device of claim 23, further comprising a self-oscillation dampener for controlling amplitudes of oscillations of the plate member.

27. The device of claim 23, wherein the conduit redirects a direction of flow of the exhaled air such that at the inlet the direction of flow is substantially parallel to a plate of the plate member and at the plate member the direction of flow is substantially normal to the plane of the plate member.

28. A method for measuring respiratory air flow, comprising:

(a) exhaling air into an inlet of a conduit;

(b) moving a plate member that is movably disposed in the conduit downstream of the inlet, the plate member at least partially blocking the conduit and moving in response to the passage of the exhaled air through the conduit, wherein the plate member includes a plurality of holes passing therethrough;

(c) passing air located on a first side of the plate member through the plurality of holes to maintain a resonant frequency of the plate member at or above a selected level, wherein the exhaled air contacts a second side of the plate member that is opposite to the first side of the plate member, and wherein the selected level is higher than a frequency of oscillations imparted to the plate member by the exhaled air; and

(d) measuring at least one of a force and a pressure applied to the plate member by the exhaled air and the location of the plate member.

29. The method of claim 28, wherein the measuring step includes:

contacting the plate member with a radiant beam; and

receiving a reflected radiant beam with a detector.

30. The method of claim 29, wherein the plate member includes a bar code for encoding the reflected radiant beam.

31. The method of claim 29, further comprising a self-oscillation dampener to control an amplitude of oscillations of the plate member.

32. The method of claim 28, wherein the measuring step includes:

measuring the location of the plate member at a plurality of points in time and generating a plurality of location signals; and

processing the plurality of location signals to determine a desired air flow parameter.

33. The method of claim 28, wherein said at least one of a force and a pressure is a force.

34. A device for measuring respiratory air flow, comprising:

(a) a conduit having an inlet for exhaled air and an outlet for the exhaked air; and

(b) a sensing member for measuring an air flow parameter, wherein a first direction of air flow through the inlet is transverse to a second direction of air flow at the sensing member, wherein a third direction of air flow at the outlet located downstream of the sensing member is transverse to the first and second directions of flow, and wherein the sensing member is movably disposed in the conduit between the inlet and the outlet, the sensing member at least partially blocking the conduit and moving in response to the passage of the exhaled air through the conduit.

35. The device of claim 34, wherein the sensing member includes one or more stiffening members to control a resonant frequency of the sensing member.

36. The device of claim 34, further comprising a self-oscillation dampener for controlling an amplitude of oscillations of the sensing member.

37. The device of claim 36, wherein the self-oscillation dampener includes at least one of a plurality of holes in the sensing member and a plurality of eddy currents in a portion of the sensing member, the eddy currents being imparted to the sensing member by an electromagnetic field.

38. The device of claim 34, wherein a plane defined by a face of the sensing member is substantially parallel to the first direction of air flow.

39. The device of claim 34, wherein a plane of movement of the sensing member is transverse to the first direction of air flow.

40. A method for measuring respiratory air flow, comprising:

(a) passing exhaled air through an inlet of a conduit, the exhaled air having a first direction of flow through the inlet;

(b) contacting the exhaled air with a moveable sensing member located in the conduit between the inlet and an outlet, the exhaled air having a second direction flow adjacent to the sensing member and the sensing member at least partially blocking the conduit and moving in response to the passage of the exhaled air through the conduit;

(c) measuring an air flow parameter using a signal generated in response to movement of the sensing member in the conduit between the inlet and outlet, wherein the first direction of flow is transverse to the second direction of flow; and

(d) passing the exhaled air through the outlet, the outlet being located downstream of the sensing member, wherein a third direction of flow of the exhaled air at the outlet is transverse to the first and second directions of flow.

41. The method of claim 40, wherein the measuring step includes:

contacting the sensing member with a radiant beam; and

receiving a reflected beam with a detector.

42. The method of claim 41, wherein the sensing member includes a bar code for encoding the reflected radiant beam.

43. The method of claim 40, further comprising a self-oscillation dampener to control an amplitude of oscillations of the sensing member.

44. The method of claim 40, wherein the first direction of flow is substantially normal to the second direction of flow.

45. The method of claim 40, wherein the measuring step includes:

measuring the location of the sensing member at a plurality of points in time and generating a plurality of location signals; and

processing the plurality of location signals to determine a desired air flow parameter.

46. A device for measuring respiratory air flow, comprising:

(a) a conduit having an inlet for exhaled air and an outlet for the exhaled air;

(b) a plate member movably disposed in the conduit between the inlet and the outlet, the plate member at least partially blocking the conduit and moving in response to the passage of the exhaled air through the conduit, wherein movement of the plate member permits the exhaled air to flow around the plate member; and

(c) a measuring device for measuring at least one of a pressure and a force applied against the plate member by the exhaled air and generating a measurement signal, the measuring device being located on the plate member.

47. The device of claim 46, wherein said at least one of a pressure and a force is a force.

48. The device of claim 46, wherein the plate member includes one or more stiffening members to control a resonant frequency of the plate member.

49. The device of claim 46, further comprising a self-oscilation dampener for controlling an amplitude of oscillations of the plate member.

50. The device of claim 49, wherein the self-oscillation dampener includes at least one of a plurality of holes in the plate member and a plurality of eddy currents in a portion of the plate member, the eddy currents being imparted to the plate member by an electromagnetic field.

51. The device of claim 46, wherein an orifice is located between the plate member and a wall of the conduit, the exhaled air having a first direction of flow at the inlet and a second direction of flow at the orifice and the first direction of flow is transverse to the second direction of flow.

52. The device of claim 51, wherein a plane defined by a face of the plate member is substantially parallel to the first direction of air flow at the inlet.

53. The device of claim 51, wherein a plane of movement of the plate member is transverse to the first direction of air flow at the inlet.

54. A device for measuring respiratory air flow, comprising:

(a) a conduit having an inlet for exhaled air and an outlet for the exhaled air;

(b) a sensing member movably disposed in the conduit between the inlet and the outlet, the sensing member at least partially blocking the conduit and moving in response to the passage of the exhaled air through the conduit; and

(c) a measuring device for measuring, at a plurality of points in time, the location of the sensing member and generating a plurality of location signals wherein the measuring device includes a sound emitter in communication with a sound detector; and

(d) a processing unit, in communication with the measuring device, for receiving the plurality of location signals and determining a plurality of positions of the sensing member that correspond to the plurality of location signals.

55. The device of claim 54, further comprising:

(e) an electronic memory, in communication with the processing unit, for recording the plurality of locations at the plurality of points in time.

56. The device of claim 54, wherein the conduit redirects a direction of flow of the exhaled air such that at the inlet the direction of flow is substantially parallel to a surface of the sensing member and at the sensing member the direction of flow is substantially normal to the surface of the sensing member.

57. The device of claim 54, further comprising a self-oscillation dampener to resist movement of the sensing member.

58. The device of claim 54, wherein the sound is emitted as ultrasound energy.

59. The device of claim 54, wherein the sensing member includes or engages one or more stiffening members to impart rigidity to the sensing member.

60. The device of claim 59, wherein the one or more stiffening members are located on a downstream surface of the sensing member relative to the direction of exhaled air flow.

61. A method for determining exhaled air flow, comprising:

(a) exhaling air into an inlet of a conduit;

(b) moving a sensing member that is movably disposed in the conduit downstream of the inlet, the sensing member at least partially blocking the conduit and moving in response to the passage of the exhaled air through the conduit;

(c) emitting sound energy;

(d) receiving reflected sound energy that is reflected by the sensing member;

(e) determining a location of the sensing member and generating a location signal; and

(f) processing the location signal to determine a desired air flow parameter.

62. The method of claim 61, further comprising a self-oscillation dampener to control an amplitude of oscillation of the sensing member.

63. The method of claim 61, wherein the sound energy is emitted by one or more piezoelectric crystals.

64. The system of claim 61, wherein the sound energy is modulated.

65. The method of claim 61, wherein the conduit redirects a direction of flow of the exhaled air such that at the inlet the direction of flow is substantially parallel to a surface of the sensing member and at the sensing member the direction of flow is substantially normal to the surface of the sensing member.

66. The method of claim 61, wherein the receiving step includes:

contacting the sensing member with sound energy; and

receiving the reflected sound energy with a detector.

67. The method of claim 66, wherein the sensing member includes a bar code for encoding the reflected sound energy beam.

68. The method of claim 61, wherein the sensing member includes one or more stiffening members to control a resonant frequency of the sensing member.

69. A device for measuring respiratory air flow, comprising:

(a) a conduit having an inlet for exhaled air and an outlet for the exhaled air; and

(b) a sensing member for measuring an air flow parameter, wherein a direction of air flow through the inlet is transverse to a direction of air flow at the sensing member, wherein the sensing member is movably disposed in the conduit between the inlet and outlet, the sensing member at least partially blocking the conduit and moving in response to the passage of the exhaled air through the conduit, and wherein the sensing member includes one or more stiffening members to control a resonant frequency of the sensing member.

70. The device of claim 69, further comprising a self-oscillation dampener for controlling an amplitude of oscillations of the sensing member.

71. The device of claim 70, wherein the self-oscillation dampener includes at least one of a plurality of holes in the sensing member, and a plurality of eddy currents in a portion of the sensing member, the eddy currents being imparted to the sensing member by an electromagnetic field.

72. The device of claim 69, wherein a plane defined by a face of the sensing member is substantially parallel to the direction of air flow at the inlet.

73. The device of claim 69, wherein a plane of movement of the sensing member is transverse to the direction of air flow at the inlet.

74. A device for measuring respiratory air flow, comprising:

(a) a conduit having an inlet for exhaled air and an outlet for the exhaled air;

(b) a sensing member for measuring an air flow parameter, wherein a direction of air flow through the inlet is transverse to a direction of air flow at the sensing member and wherein the sensing member is movably disposed in the conduit between the inlet and outlet, the sensing member at least partially blocking the conduit and moving in response to the passage of the exhaled air through the conduit; and

(c) a self-oscillation dampener for controlling an amplitude of oscillations of the sensing member.

75. The device of claim 74, wherein the sensing member includes one or more stiffening members to control a resonant frequency of the sensing member.

76. The device of claim 74, wherein the self-oscillation dampener includes at least one of a plurality of holes in the sensing member, and a plurality of eddy currents in a portion of the sensing member, the eddy currents being imparted to the sensing member by an electromagnetic field.

77. The device of claim 74, wherein a plane defined by a face of the sensing member is substantially parallel to the direction of air flow through the inlet.

78. The device of claim 74, wherein a plane of movement of the sensing member is transverse to the direction of air flow through the inlet.

79. A device for measuring respiratory air flow, comprising:

(a) a conduit having an inlet for exhaled air and an outlet for the exhaled air;

(b) a plate member movably disposed in the conduit between the inlet and the outlet, the plate member at least partially blocking the conduit and moving in response to the passage of the exhaled air through the conduit; and

(c) a measuring device for measuring at least one of a pressure and a force applied against the plate member by the exhaled air and generating a measurement signal, the measuring device being located on the plate member, wherein an orifice is located between the plate member and a wall of the conduit, wherein the exhaled air has a first direction of flow at the inlet and a second direction of flow at the orifice and the first direction of flow is transverse to the second direction of flow, and wherein a plane defined by a face of the plate member is substantially parallel to the first direction of air flow at the inlet.

80. The device of claim 79, wherein said at least one of a pressure and a force is a force.

81. A device for measuring respiratory air flow, comprising:

(a) a conduit having an inlet for exhaled air and an outlet for the exhaled air;

(b) a plate member movably disposed in the conduit between the inlet and the outlet, the plate member at least partially blocking the conduit and moving in response to the passage of the exhaled air through the conduit; and

(c) a measuring device for measuring at least one of a pressure and a force applied against the plate member by the exhaled air and generating a measurement signal, the measuring device being located on the plate member, wherein an orifice is located between the plate member and a wall of the conduit, wherein the exhaled air has a first direction of flow at the inlet and a second direction of flow at the orifice and the first direction of flow is transverse to the second direction of flow, and wherein a plane of movement of the plate member is transverse to the first direction of air flow at the inlet.

82. The device of claim 81, wherein said at least one of a pressure and force is a force.