Hand-held non-invasive blood pressure measurement device

• US 5,941,828 A
• Filed: 08/15/1997
• Issued: 08/24/1999
• Est. Priority Date: 11/09/1993
• Status: Expired due to Fees

• Current Assignee: Medwave, Inc.
• Original Assignee: Medwave, Inc.
• Inventors: Thede, Roger C., Curran, Timothy G., Poliac, Marius O., Archibald, G. Kent, Danielson, Orland H.
• Primary Examiner(s): GILBERT, SAMUEL G
• Application Number:
  US08/912,139
• Time in Patent Office: 739 Days
• Field of Search: 600/485, 600/490-499
• US Class Current: 600/494
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 5/02116 of pulse wave amplitude A61B5/02225 takes precedence
• CPC Class Codes: A61B 5/02233 Occluders specially adapted therefor tourniquets A61B17/132
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure

Abstract

A hand-held non-invasive blood pressure measurement device allows a varying pressure to be applied to an artery while pressure waveforms are sensed to produce pressure waveform data. Waveform parameters are derived from the sensed pressure waveform data. Blood pressure is then determined using the derived parameters. The user is guided or prompted to apply the varying pressure through audible and visual feedback.

Claims

1. A method for determining blood pressure of an artery having a pulse, the method comprising:

manually applying pressure to the artery;

sensing pressure data produced by the artery;

guiding the manually applying of pressure based upon the sensed pressure data;

deriving a plurality of parameters from the sensed pressure data; and

determining a blood pressure value based upon the parameters.

2. The method of claim 1 wherein guiding the manually applying comprises producing a feedback signal which changes as a function of the sensed pressure data.

3. The method of claim 2 wherein the feedback signal is an audible signal.

4. The method of claim 3 wherein the audible signal changes in frequency as a function of pressure waveform amplitude derived from the sensed pressure data.

5. The method of claim 3 wherein the audible signal changes in volume as a function of pressure waveform amplitude derived from the sensed pressure data.

6. A method for determining blood pressure of an artery, the method comprising:

manually applying pressure to the artery so that the artery exhibits a plurality of pressure waveforms;

producing sensed pressure waveform data representing each of the plurality of pressure waveforms;

guiding the manually applying of pressure based upon the sensed pressure waveform data;

deriving a plurality of parameters from the sensed pressure waveform data; and

determining a blood pressure value based upon the parameters.

7. The method of claim 6 wherein guiding the manually applying comprises producing a feedback signal which changes as a function of the sensed pressure data.

8. The method of claim 7 wherein the feedback signal is an audible signal.

9. The method of claim 8 wherein the audible signal changes in frequency as a function of pressure waveform amplitude derived from the sensed pressure data.

10. The method of claim 8 wherein the audible signal changes in volume as a function of pressure waveform amplitude derived from the sensed pressure data.

11. A non-invasive blood pressure measurement device, the measurement device comprising:

manually-operated pressure means for manually applying pressure to the artery so that the artery exhibits pressure data;

sensing means for sensing the pressure data;

signal producing means connected to the sensing means for producing output signals corresponding to the sensed pressure data;

means for guiding a user to manually apply pressure based upon the output signals; and

processing means for receiving the output signals from the signal producing means, for deriving a plurality of parameters using sensed pressures and for determining a blood pressure value using the derived parameters.

12. The measurement device of claim 11, wherein the means for guiding produces a feedback signal which changes as a function of the sensed pressure data.

13. The measurement device of claim 12 wherein the feedback signal is an audible signal.

14. The measurement device of claim 13 wherein the audible signal changes in frequency as a function of pressure waveform amplitude derived from the sensed pressure data.

15. The measurement device of claim 13 wherein the audible signal changes in volume as a function of pressure waveform amplitude derived from the sensed pressure data.

16. The measurement device of claim 11 wherein the manually-operated pressure means comprises:

a housing shaped to be gripped by a user to apply force toward the artery.

17. The measurement device of claim 16 wherein the sensing means includes:

a transducer having a sensing surface;

a flexible diaphragm for being positioned over the underlying artery; and

interface means between the flexible diaphragm and the sensing surface of the transducer for transmitting pressure pulses from the diaphragm to the transducer.

18. The measurement device of claim 17 wherein the flexible diaphragm is mounted on a sensor interface assembly which is pivotally connected to the housing.

19. A non-invasive blood pressure measurement system comprising:

means for manually applying pressure to an artery;

means for sensing pressure from the artery over time while the pressure is applied to the artery to generate pressure data;

means for guiding a user to manually apply the pressure; and

means for deriving a pressure value based upon a waveform analysis of the pressure data.

20. The measurement device of claim 19, wherein the means for guiding produces a feedback signal which changes as a function of the sensed pressure data.

21. The measurement device of claim 19 wherein the feedback signal is an audible signal.

22. The measurement device of claim 19 wherein the audible signal changes in frequency as a function of pressure waveform amplitude denied from the sensed pressure data.

23. The measurement device of claim 19 wherein the audible signal changes in volume as a function of pressure waveform amplitude derived from the sensed pressure data.

24. The measurement device of claim 19 wherein the manually-operated pressure means comprises:

a housing shaped to be gripped by a user to apply force toward the artery.

25. The measurement device of claim 24 wherein the sensing means includes:

a transducer having a sensing surface;

a flexible diaphragm for being positioned over the underlying artery; and

interface means between the flexible diaphragm and the sensing surface of the transducer for transmitting pressure pulses from the diaphragm to the transducer.

26. The measurement device of claim 25 wherein the flexible diaphragm is mounted on a sensor interface assembly which is pivotally attached to the housing.

27. A method of determining blood pressure, the method comprising:

applying pressure to an artery;

sensing pressure over time while the pressure is applied to the artery to generate pressure waveform data for pressure waveforms representing a plurality of beats;

guiding the applying of pressure based upon the pressure waveform data;

detecting onset of the beats from the waveform data;

extracting waveform parameters using a detected onset of one of the beats; and

determining a blood pressure value based upon the waveform parameters.

28. The method of claim 27 wherein guiding the applying comprises producing a feedback signal which varies as a function of the sensed pressure data.

29. A method for determining blood pressure of an artery having a pulse, the method comprising:

applying pressure to the artery;

sensing pressure data produced by the artery;

guiding the applying of pressure based upon the sensed pressure data;

deriving a plurality of different parameters from the sensed pressure data; and

determining a blood pressure value as a function of the plurality of different parameters.

30. The method of claim 29 wherein guiding the applying comprises producing a feedback signal which varies as a function of the sensed pressure data.

31. A method for determining blood pressure of an artery having a pulse, the method comprising:

sensing pressure data produced by the artery while manually applying pressure to the artery;

guiding the manually applying of pressure based upon the sensed pressure data;

deriving parameters from the sensed pressure data; and

determining a blood pressure value based upon the parameters.

32. The method of claim 31 wherein guiding the applying comprises producing a feedback signal which varies as a function of the sensed pressure data.

33. The method of claim 32 wherein the feedback signal is an audible signal.

34. The method of claim 32 wherein the feedback signal is a visual signal.

35. A method for determining blood pressure of an artery having a pulse, the method comprising:

manually applying pressure to the artery;

sensing pressure data produced by the artery;

guiding the manually applying of pressure based upon the sensed pressure data;

deriving a plurality of parameters from the sensed pressure data; and

determining a blood pressure value based upon the plurality of parameters and a stored set of coefficients.

36. The method of claim 35 including:

selecting a set of data from a plurality of beats including a maximum amplitude beat, wherein at least one parameter is derived from the selected set of data.

37. The method of claim 35 wherein deriving a plurality of parameters from the sensed pressure data includes deriving a relative amplitude value and at least one waveform shape parameter.

38. The method of claim 35 wherein deriving a plurality of parameters includes deriving parameters of a curve generated from the sensed pressure data.

39. The method of claim 35 wherein a first pressure is applied to the artery at a starting point of a waveform and wherein a second pressure is applied to the artery at an ending point of the waveform and wherein deriving a plurality of parameters includes adjusting the waveform so that the starting point and the ending point of the waveform have equal pressure amplitudes.

40. The method of claim 35 including:

scaling a pressure waveform to eliminate gain, wherein the parameters are derived from the scaled pressure waveform.

41. The method of claim 35 wherein deriving a plurality of parameters includes deriving at least one parameter selected from a group consisting of:

(a) rise time of a selected portion of a waveform, (b) slope of a portion of a waveform, (c) applied pressure corresponding to a starting point of a waveform, (d) applied pressure corresponding to an ending point of a waveform, (e) pressure of a waveform at a selected time, (f) a pressure corresponding to a selected point on a waveform, (g) a time value corresponding to a width of a selected portion of a waveform, (h) mean amplitude of a waveform, (i) an applied pressure corresponding to a selected point of a waveform, and (j) mean of a curve generated from data taken from a plurality of waveforms.

42. The method of claim 35 wherein deriving a plurality of parameters includes:

deriving at least one parameter other than pressure waveform amplitude from the sensed pressure data.

43. The method of claim 35 wherein the step of applying a varying pressure to the artery includes:

applying an increasing pressure to the artery.

44. The method of claim 35 including:

creating pressure waveform data of pressure waveforms representing a plurality of beats from the sensed pressure data;

detecting onset of the beats from the waveform data; and

deriving at least one parameter using a detected onset of one of the beats.

45. A non-invasive blood pressure monitoring device, the monitoring device comprising:

manually-operated pressure means for applying a pressure to the artery so that the artery exhibits pressure data;

means for guiding a user in applying pressure to the artery with the manually operated pressure means based upon the pressure data;

sensing means for sensing the pressure data;

signal producing means connected to the sensing means for producing output signals corresponding to the sensed pressure data;

storing means for storing a set of coefficients; and

processing means for receiving the output signals from the signal producing means, for deriving a plurality of parameters using sensed pressures and for determining a blood pressure value using the derived parameters and the stored set of coefficients.

46. The measurement device of claim 45, wherein the means for guiding produces a feedback signal which changes as a function of the sensed pressure data.

47. The measurement device of claim 45 wherein the feedback signal is an audible signal.

48. The measurement device of claim 45 wherein the audible signal changes in frequency as a function of pressure waveform amplitude derived from the sensed pressure data.

49. The measurement device of claim 45 wherein the audible signal changes in volume as a function of pressure waveform amplitude derived from the sensed pressure data.

50. The measurement device of claim 45 wherein the manually-operated pressure means comprises:

a housing shaped to be gripped by a user to apply force toward the artery.

51. The measurement device of claim 50 wherein the sensing means includes:

a transducer having a sensing surface;

a flexible diaphragm for being positioned over the underlying artery; and

interface means between the flexible diaphragm and the sensing surface of the transducer for transmitting pressure pulses from the diaphragm to the transducer.

52. The measurement device of claim 51 wherein the flexible diaphragm is mounted on a sensor interface assembly which is pivotally attached to the housing.

53. A method for monitoring pressure waveform data produced by an artery, the method comprising:

manually applying pressure to the artery beginning with an initial pressure and ending with a final non-occluding pressure so that the artery exhibits a plurality of pressure waveforms; and

sensing pressure waveform data produced by the artery representing each of the plurality of pressure waveforms, wherein the final non-occluding pressure applied to the artery is determined based upon the pressure waveform data sensed while pressure is applied to the artery.

54. The method of claim 53 and further comprising:

producing a feedback signal which changes as a function of the sensed pressure data.

55. The method of claim 54 wherein the feedback signal is an audible signal.

56. The method of claim 55 wherein the audible signal changes in frequency as a function of pressure waveform amplitude derived from the sensed pressure data.

57. The method of claim 55 wherein the audible signal changes in volume as a function of pressure waveform amplitude derived from the sensed pressure data.

58. The method of claim 53 and further comprising:

guiding the manually applying of the increasing pressure based upon the pressure waveform data.

59. A method for monitoring blood pressure parameters of an artery, the method comprising:

sensing pressure data produced by the artery over time representing a plurality of arterial pressure waveforms;

determining a maximum pressure amplitude for each of the plurality of arterial pressure waveforms from the sensed pressure data; and

manually applying pressure to the artery while the pressure data is sensed based upon the maximum pressure amplitudes.

60. The method of claim 59 wherein the step of manually applying an increasing pressure to the artery includes:

manually applying the increasing pressure to the artery until at least one waveform has a maximum pressure amplitude less than a maximum pressure amplitude of a preceding waveform.

61. The method of claim 59 and further comprising:

prompting the manually applying of the increasing pressure based upon the pressure data sensed.

62. The method of claim 61 wherein prompting the manually applying comprises producing a feedback signal which changes as a function of the sensed pressure data.

63. The method of claim 62 wherein the feedback signal is an audible signal.

64. The method of claim 63 wherein the audible signal changes in frequency as a function of pressure waveform amplitude derived from the sensed pressure data.

65. The method of claim 63 wherein the audible signal changes in volume as a function of pressure waveform amplitude derived from the sensed pressure data.

66. A method for monitoring blood pressure data produced by an artery, the method comprising:

sensing pressure data produced by the artery over time representing a plurality of arterial pressure waveforms;

determining a maximum pressure amplitude for each of the plurality of arterial pressure waveforms from the sensed pressure data; and

manually applying pressure to the artery until at least one waveform has a maximum pressure amplitude less than a maximum pressure amplitude of a preceding waveform.

67. The method of claim 66 and further comprising:

guiding the manually applying of increasing pressure based upon the sensed pressure data.

68. The method of claim 67 wherein guiding the manually applying comprises producing a feedback signal which changes as a function of the sensed pressure data.

69. The method of claim 68 wherein the feedback signal is an audible signal.

70. The method of claim 69 wherein the audible signal changes in frequency as a function of pressure waveform amplitude derived from the sensed pressure data.

71. The method of claim 69 wherein the audible signal changes in volume as a function of pressure waveform amplitude derived from the sensed pressure data.

72. A method for determining blood pressure of an artery, the method comprising:

positioning a sensor having a constant volume fluid filled sensing chamber over the artery;

manually applying force to the sensor to press the sensor towards the artery;

sensing pressure data produced by the artery by sensing pressure within the constant volume fluid filled chamber to generate pressure waveform data;

guiding the manually applying force based upon the pressure data;

deriving parameters from the pressure data; and

determining a blood pressure value based upon the parameters.

73. The method of claim 72 wherein the step of manually applying force to the sensor includes:

manually applying an increasing force to the sensor.

74. The method of claim 73 wherein guiding the manually applying comprises producing a feedback signal which changes as a function of the sensed pressure data.

75. The method of claim 74 wherein the feedback signal is an audible signal.

76. The method of claim 75 wherein the audible signal changes in frequency as a function of pressure waveform amplitude derived from the sensed pressure data.

77. A non-invasive blood pressure measurement device comprising:

a sensor having a constant volume fluid filled sensing chamber configured for being positioned over an underlying artery;

manual force applying means for applying a force to the sensor to press the sensor against the underlying artery;

sensing means for sensing pressure within the constant volume fluid filled sensing chamber representing pressure data produced by the underlying artery;

prompting means for prompting a user to apply a force to the manual force applying means;

signal producing means connected to the sensing means for producing output signals corresponding to the sensed pressures within the constant volume fluid filled sensing chamber;

storing means for storing a set of coefficients; and

processing means for receiving the output signals from the signal producing means, for deriving a plurality of parameters using the sensed pressures and for determining a blood pressure value using the derived parameters and the stored set of coefficients.

78. A non-invasive blood pressure measurement device comprising:

a sensor having a constant volume fluid filled sensing chamber configured for being positioned over an underlying artery;

means for manually applying force to the sensor to press the sensor against the underlying artery;

sensing means for sensing pressure within the constant volume fluid filled sensing chamber;

means for prompting a user to manually apply force to the sensor based upon the sensed pressure; and

means for deriving a blood pressure value based upon a waveform analysis of the sensed pressure.

79. A method of non-invasive blood pressure measurement, the method comprising:

positioning a pressure sensor over an underlying artery;

prompting a user to apply force to press the sensor against the underlying artery;

deriving a blood pressure value based upon a waveform analysis of sensed pressure data.

80. The method of claim 79 wherein prompting the user is a function of the sensed pressure data.

81. A device for sensing blood pressure within an underlying artery of a patient, the device comprising:

a fluid filled sensing chamber having a diaphragm;

a transducer fluidly coupled to the fluidly filled sensing chamber, wherein the transducer senses fluid pressure within the chamber;

a flexible body conformable wall proximate the sensing chamber and isolated from the sensing chamber for applying force to the artery while preventing pressure in a direction generally parallel to the artery from being applied to the sensing chamber; and

a housing connected to the wall for applying force to apply pressure to the artery.

82. A device for sensing blood pressure pulses within an underlying artery surrounded by tissue as the underlying artery is compressed, the sensor comprising:

a transducer;

a flexible diaphragm for placement above the underlying artery;

a fluid coupling medium between the transducer and the flexible diaphragm, wherein the fluid coupling medium transmits blood pressure pulse signals from the underlying artery to the transducer;

a flexible, variable height, body conforming sidewall isolated from the fluid coupling medium and positioned for engaging tissue proximate to the underlying artery; and

means for manually applying force to the sidewall.

83. A device for external measurements of blood pressure in an underlying artery surrounded by tissue of a patient, the system comprising:

sensing means for sensing blood pressure pulses in the underlying artery;

means for manually applying a variable pressure to the sensing means; and

means for calculating blood pressure based upon a pressure at maximum energy transfer and shape of the sensed pressure pulses within the underlying artery.

84. The device of claim 83 wherein the sensing means includes:

a transducer having a sensing surface;

a flexible diaphragm for being positioned over the underlying artery; and

interface means between the flexible diaphragm and the sensing surface of the transducer for transmitting pressure pulses from the diaphragm to the transducer.