Portable blood pressure measuring device and method of measuring blood pressure

• US 5,485,848 A
• Filed: 06/04/1992
• Issued: 01/23/1996
• Est. Priority Date: 01/31/1991
• Status: Expired due to Term

• Current Assignee: Harry E. Jackson, Sandra R. Jackson
• Original Assignee: Harry E. Jackson, Sandra R. Jackson
• Inventors: Jackson, Sandra R., Jackson, Harry E.
• Primary Examiner(s): Sykes, Angela D.
• Application Number:
  US07/893,287
• Time in Patent Office: 1,328 Days
• Field of Search: 128/672, 128/679, 128/687, 128/689, 128/690, 128/666.7
• US Class Current: 600/485
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/02116 of pulse wave amplitude A61B5/02225 takes precedence
• CPC Class Codes: A61B 5/022 by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/681 Wristwatch-type devices
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure

Abstract

A non-invasive, non-intrusive, convenient and portable device for monitoring a user'"'"'s arterial blood pressure is provided. The continuous blood pressure monitoring device includes a transducer mounted to detect arterial wall movement caused by blood flow through an artery of the user and means for measuring the output signals of the transducer and accurately converting these signals to systolic and diastolic blood pressure readings on a continuous basis. Calibration data is collected by periodically comparing transducer output signals and the simultaneous outputs of a separate diagnostically accurate blood pressure measuring device (such as a cuff sphygmomanometer), which is not coupled to the device during normal blood pressure monitoring. Blood pressure is computed from the measured transducer output signals and the calibration data.

Claims

1. A method of blood pressure monitoring, comprising the steps of:

mounting a transducer on a user'"'"'s body so that it detects at least one of spatial displacement and pressure variations caused by blood flow through an artery;

mounting a blood pressure measuring device which provides accurate and diagnostically meaningful blood pressure results on a user'"'"'s body;

collecting calibration data for the transducer while so mounted by comparing a transducer output signal with an output from said blood pressure measuring device;

determining a base pressure applied to the transducer by the step of mounting the transducer to maintain substantially constant pressure on the transducer within a predetermined range of values;

disconnecting said blood pressure measuring device from the user'"'"'s body;

after disconnecting said blood pressure measuring device, measuring the output signals of the mounted transducer; and

computing blood pressure from at least said measured transducer output signals and said calibration data.

2. The method of claim 1, including the step of determining whether the measured output signals of the mounted transducer constitute a usable blood pressure measurement.

3. The method of claim 1, wherein said step of collecting calibration data includes receiving the outputs of said accurate and diagnostically meaningful blood pressure measuring device, simultaneously measuring the output signals of the mounted transducer and storing the measured values from the measured output signals of the transducer and corresponding outputs from the diagnostically accurate blood pressure measuring device as a calibration table for use in said computing step.

4. The method of claim 3, wherein said calibration further includes determining whether said measured output signals of the mounted transducer are usable for blood pressure measurement, and using only usable data and corresponding outputs of the accurate and diagnostically meaningful blood pressure measuring device to form the calibration table.

6. The method of claim 1, including the further step of evaluating a computed blood pressure to determine if it falls within a predetermined range, and activating an alarm detectable by the user when the computed blood pressure falls outside of said range.

7. The method of claim 1, wherein, and the steps of mounting the transducer on a user'"'"'s body, collecting calibration data, determining the pressure applied to the transducer, measuring output signals of said mounted transducer and computing blood pressure are perfomed by a portable unit separate from but adapted to be operably connected to said diagnostically accurate blood pressure measuring device during said collecting calibration data step and disconnected thereafter.

8. The method of claim 7, wherein the portable unit is operably coupled to the diagnostically accurate blood pressure measuring device during the calibration step by a wireless transmission.

9. The method of claim 7, wherein the portable unit is operably coupled to the diagnostically accurate blood pressure measuring device during the calibration step by a removable cable connection.

10. The method of claim 7, and including forming the diagnostically accurate blood pressure measuring device as a cuff sphygmomanometer.

11. The method of claim 7, wherein the portable unit is shaped and sized to be mounted on the user on a continuous basis during the measuring and computing steps without interfering with the user'"'"'s normal activities.

12. The method of claim 11, and including forming said portable unit in the shape of a wristwatch suitable for mounting on the wrist of a user.

13. The method of claim 1, and including forming the transducer to provide output signals representative of the movement of an arterial wall in response to the pumping of blood by the heart.

14. The method of claim 1, including the further step of automatically maintaining the base pressure on the transducer within a predetermined range of values in response to the determined values of the pressure applied to the transducer by the mounting step.

15. The method of claim 1, including the further step of manually monitoring the base pressure on the transducer within a predetermined range of values in response to the determined value of the base pressure applied to the transducer by the mounting step.

16. The method of claim 1, and including forming the transducer to provide an output signal representative of the base pressure applied thereto by the mounting step for use in the determining step.

17. The method of claim 1, and including computing said blood pressure from at least the measured transducer output, said calibration data and data interpretation criteria.

18. The blood pressure monitoring method of claim 1, including the step of selecting a blood pressure measuring device which is accepted by the medical community as providing accurate and diagnostically meaningful blood pressure results.

5. A method of blood pressure monitoring, comprising the steps:

mounting a transducer on a user'"'"'s body so that it detects at least one of spatial displacement and pressure variations caused by blood flow through an artery;

collecting calibration data for the transducer while so mounted by comparing a transducer output signal with an output from a blood pressure measuring device which provides accurate and diagnostically meaningful blood pressure results;

determining a base pressure applied to the transducer by the mounting step to maintain substantially constant pressure on the transducer within a predetermined range of values;

measuring the output signals of said mounted transducers;

computing blood pressure from at least said measured transducer output signals and said calibration data; and

evaluating a computed blood pressure to determine if it falls within a predetermined range, and storing at least values outside of said range.

19. A method of blood pressure monitoring, comprising the steps of:

mounting a transducer on a user'"'"'s body so that it detects at least one of spatial displacement and pressure variations caused by blood flow through an artery;

operatively couple an accurate and diagnostically meaningful blood pressure measuring device which provides accurate and diagnostically meaningful blood pressure results to a user'"'"'s body and operatively coupling the transducer and diagnostically meaningful blood pressure measuring device;

collecting calibration data for the transducer while so mounted by comparing a transducer output signal with an output from said diagnostically meaningful blood pressure measuring device to provide a stored calibration table having a plurality of values;

operatively separating the transducer and diagnostically meaningful blood pressure measuring device and physically disconnecting the diagnostically meaningful blood pressure measuring device from the user'"'"'s body, so that the collection of calibration data is discontinued;

after separating and disconnecting the blood pressure measuring device, measuring the output signals of the mounted transducer; and

computing blood pressure from at least the transducer output signals and said calibration data from said calibration table.

20. The method of claim 19, including the step of determining whether the measured output signals of said mounted transducer constitute a usable blood pressure measurement.

21. The method of claim 19, wherein said step of collecting calibration data includes receiving the outputs of said diagnostically accurate blood pressure measuring device, simultaneously measuring output signals of said mounted transducer and storing the measured values from the measured output signals of the transducer and corresponding outputs from the diagnostically accurate blood pressure measuring device as a calibration table for use in said computing step.

22. The method of claim 21, wherein said calibration further includes determining whether said measured output signals of said mounted transducer are usable for blood pressure measurement, and using only usable data and corresponding outputs of the diagnostically accurate blood pressure measuring device to form the calibration table.

23. The method of claim 19, including the further step of evaluating a computed blood pressure to determine if it falls within a predetermined range, and storing at least values outside of said range.

24. The method of claim 19, including the further step of evaluating a computed blood pressure to determine if it falls within a predetermined range, and activating an alarm detectable by the user when the computed blood pressure falls outside of said range.

25. The method of claim 19, wherein and the steps of mounting the transducer on a user'"'"'s body, collecting calibration data, determining the pressure applied to the transducer, measuring outputs of said mounted transducer and computing blood pressure are performed by a portable unit separate from but adapted to be operably connected to said diagnostically accurate blood pressure measuring device during said collecting calibration data step and disconnected thereafter.

26. The method of claim 25, and including shaping and sizing the portable unit so that it may be mounted on the user on a continuous basis during the measuring and computing steps without interfering with the user'"'"'s normal activities.

27. The method of claim 26, and including forming the portable unit in the shape of a wristwatch suitable for mounting on the wrist of a user.

28. The method of claim 25, and including operably coupling the portable unit to the accurate and diagnostically meaningful blood pressure measuring device during the calibration step by a wireless transmission.

29. The method of claim 25, and including operably coupling the portable unit to the accurate and diagnostically meaningful blood pressure measuring device during the calibration step by a removable cable connection.

30. The method of claim 25, and including forming the accurate and diagnostically meaningful blood pressure measuring device as a cuff sphygmomanometer.

31. The method of claim 19, and including forming the transducer to provide output signals representative of the movement of an arterial wall in response to the pumping of blood by the heart.

32. The method of claim 19, and including forming the transducer to provide an output representative of the base pressure applied thereto by the mounting step for use in the determining step.

33. The method of claim 19, and including the further step of determining the base pressure applied to the transducer by the mounting step and determining if that pressure is within a predetermined range of values.

34. The method of claim 33, and including the further step of manually adjusting the mounting of the transducer to set the base pressure applied to the transducer to a value within said predetermined range of values.

35. The method of claim 33, and including the further step of automatically adjusting the mounting of the transducer to bring the base pressure to within said predetermined range of values in response to the determined pressure.

36. The method of claim 33, wherein said step of determining the base pressure on the transducer is performed before collecting calibrating data and before measuring the output signals of the mounted transducer for use in computing blood pressure.

37. The method of claim 19, and including computing said blood pressure from at least measured transducer output, said calibration data and data interpretation criteria.

38. The blood pressure monitoring method of claim 19, including the step of selecting a blood pressure measuring device which is accepted by the medical community as providing accurate and diagnostically meaningful blood pressure results.

39. A blood pressure monitoring device for monitoring arterial blood pressure from an artery of a user by use of a separate diagnostically accurate blood pressure measuring device for calibration, comprising:

a transducer producing an output in response to at least one of spatial displacement and pressure variations caused by blood flow through an artery;

means for mounting said transducer on a user'"'"'s body so that the transducer can detect at least one of spatial displacement and pressure variations caused by blood flow through an artery;

means for determining the base pressure applied to the transducer by the mounting means;

means for setting said base pressure to a level within a predetermined range of values;

means for measuring signal outputs of said mounted transducer;

means for selectively providing data representative of the blood pressure of a user as measured by a diagnostically accurate blood pressure measuring device;

means for collecting said diagnostically accurate blood pressure measuring device data and measured output signals of said mounted transducer representing essentially simultaneous measurements of blood pressure and storing these collected corresponding values; and

means for computing blood pressure from at least said measured output signals of said mounted transducer and said collected corresponding values with said means for computing blood pressure and said means for collecting disconnected from said diagnostically accurate blood pressure device.

40. The blood pressure monitoring device of claim 39, wherein said blood pressure monitoring device includes a member shaped and sized to be mounted on the body of the user as a unit without interference with the normal activities of the user, said member carrying said transducer mounting means, determining means, setting means, measuring means, collecting means and computing means but being separate from said blood pressure measuring device.

41. The blood pressure monitoring device of claim 40, wherein said member is in the form of a wristwatch, said means for mounting said transducer on a user'"'"'s body comprising strap means for circling the limb of a user, and including a case supporting the components of the monitoring device carried by said member but not supported by said strap means, separate and apart from said diagnostically accurate blood pressure measuring device.

42. The blood pressure monitoring device of claim 41, wherein said transducer is mounted on said strap means.

43. The blood pressure monitoring device of claim 41, wherein said transducer is mounted within said strap means.

44. The blood pressure monitoring device of claim 41, wherein said means for setting the pressure applied to said transducer includes means for setting the effective length of said strap means adapted to extend about the limb of the user.

45. The blood pressure monitoring device of claim 44 including means supported on said case means for selectively adjusting the effective length of said strap means.

46. The blood pressure monitoring device of claim 44, wherein said strap means comprises two strap portions each having a first and second end, said two strap portions being respectively coupled on opposed sides of said case at its respective first end thereof and joinable at the respective second ends thereof, said means for adjusting the effective length of said strap means comprising means for adjusting the relative positions of the joinable second ends of said strap portions.

47. The blood pressure monitoring device of claim 41, wherein said means for selectively providing diagnostically accurate blood pressure measuring device data includes a receiver means in said unit for receiving such data by wireless transmission.

48. The blood pressure monitoring device of claim 41, wherein the means for selectively providing said diagnostically accurate blood pressure measuring device data includes cable input coupling means in said unit to which can be applied a cable carrying said diagnostically accurate blood pressure measuring device data.

49. The blood pressure monitoring device of claim 41, and including timekeeping means carried by said case and display means carried by said case for displaying time and blood pressure information.

50. The blood pressure monitoring device of claim 40, and including in said unit display means for displaying at least values of pressure applied to the transducer and computed blood pressure values.

51. The blood pressure monitoring device of claim 39, including means for determining whether the measured output signals of the mounted transducer constitute a usable blood pressure measurement.

52. The blood pressure monitoring device of claim 39, and including means for evaluating a computed blood pressure measurement to determine if it falls within a predetermined range and means for storing at least values outside said range.

53. The blood pressure monitoring device of claim 39, including alarm means, and means for evaluating a computed blood pressure to determine if it falls outside a predetermined range, and for activating said alarm means when the computed blood pressure falls outside said ranges.

54. The blood pressure monitoring device of claim 39, wherein said transducer is adapted to produce output signals representative of the movement of an arterial wall in response to the pumping of blood by the heart.

55. The blood pressure monitoring device of claim 39, wherein said diagnostically accurate blood pressure measuring device is a separate cuff sphygmomanometer.

56. The blood pressure monitoring device of claim 39, wherein said means for determining the pressure applied to the transducer by the mounting means is adapted to operate based on a measured value from said transducer.

57. The blood pressure monitoring device of claim 39, wherein said transducer is a piezoelectric transducer.

58. The blood pressure monitoring device of claim 39, wherein said transducer includes strain gauge means.

59. The blood pressure monitoring device of claim 39, wherein said transducer includes an aneroid chamber.

60. The blood pressure monitoring device of claim 39, wherein said transducer includes an optical motion sensor.

61. The blood pressure monitoring device of claim 39, wherein said computing means additionally uses data interpretation criteria.

62. A blood pressure monitoring device for monitoring arterial blood pressure from an artery of a user by use of a separate diagnostically accurate blood pressure measuring device for producing data representative of the blood pressure of the user when selectively operatively coupled to the user for calibration purposes, comprising:

a transducer for producing an output in response to variations caused by blood flow through an artery;

means for mounting said transducer on a user'"'"'s body so that said transducer can detect at least one of spatial displacement and pressure variations caused by blood flow through an artery;

means for measuring output signals of said mounted transducer;

means for collecting data from said diagnostically accurate blood pressure measuring device and measured output signals of said mounted transducer representing essentially simultaneous measurements of blood pressure by said mounted transducer and said diagnostically accurate blood pressure measuring device when operatively coupled to the user and storing a plurality of these collected corresponding values, said collecting means being operatively coupled to said mounted transducer;

means for selectively connecting said diagnostically accurate blood pressure measuring device to said means for collecting data when said diagnostically accurate blood pressure measuring device is operatively and physically coupled to the user'"'"'s body and for physically disconnecting said diagnostically accurate blood pressure measuring device from said means for collecting data when said diagnostically accurate blood pressure measuring device is not operatively and physically coupled with the user'"'"'s body; and

means operatively coupled to said transducer and to said means for collecting data for automatically computing blood pressure from said measured output signals of said mounted transducer and said collected corresponding values when said means for collecting data is disconnected from said diagnostically accurate blood pressure device, said computing means functioning even when said diagnostically accurate blood pressure measuring device is operatively and physically disconnected from the user.

63. The blood pressure monitoring device of claim 62, wherein said blood pressure monitoring device includes a member shaped and sized to be mounted on the body of the user as a unit without interference with the normal activities of the user, said member carrying said transducer, mounting means, measuring means, collecting means and said computing means but not said blood pressure measuring device.

64. The blood pressure monitoring device of claim 63, wherein said member is in the form of a wrist watch, said means for mounting said transducer on a user'"'"'s body comprising strap means for circling the limb of a user, and including a case for supporting the components of said monitoring device carried by said member and not supported by said strap means, separate and apart from said diagnostically accurate blood pressure measuring device.

65. The blood pressure monitoring device of claim 64, wherein said tranducer is mounted on said strap means.

66. The blood pressure monitoring device of claim 64, and including timekeeping means carried by said case and display means for displaying at least time and blood pressure information.

67. The blood pressure monitoring device of claim 64 and including means for determining the pressure applied to the transducer by the mounting means and means for setting said pressure to a level within a predetermined range of values.

68. The blood pressure monitoring device of claim 67, wherein said means for setting said pressure to a level within a predetermined range of values comprises a manual adjustment of the mounting means.

69. The blood pressure monitoring device of claim 68, wherein said means for setting said pressure to a level within a predetermined range of values comprises an automatic adjustment of the mounting means.

70. The blood pressure monitoring device of claim 69 including means supported on said case means for selectively adjusting the effective length of said strap means.

71. The blood pressure monitoring device of claim 67, wherein said means for setting the pressure applied to said transducer includes means for setting the effective length of said strap means extending about the limb of the user.

72. The blood pressure monitoring device of claim 71, wherein said means for determining the pressure applied to the transducer by the mounting means is adapted to operate on a measured value from said transducer means.

73. The blood pressure monitoring device of claim 67, wherein in said strap means comprises two strap portions each having a first and second end, said two strap portions being respectively coupled on opposed sides of said case at its respective first end thereof and joinable at the respective second ends thereof, said means for adjusting the effective length of said strap means comprising means for adjusting the relative positions of the joinable second ends of said strap portions.

74. The blood pressure monitoring device of claim 64, wherein said transducer is mounted within said strap means.

75. The blood pressure monitoring device of claim 63, and including display means for displaying at least computed blood pressure values carried by said member.

76. The blood pressure monitoring device of claim 63, wherein

said means for selectively connecting said diagnostically accurate blood pressure measuring device to said means for collection data includes a receiver means in said unit for receiving such data by wireless transmission.

77. The blood pressure monitoring device of claim 62, including means for determining whether the measured output signals of the mounted transducer constitute a usable blood pressure measurement.

78. The blood pressure monitoring device of claim 62, and including

means for evaluating the computed blood pressure measurement to determine if it falls within one or more predetermined ranges and means for storing at least values outside said ranges.

79. The blood pressure monitoring device of claim 62, including alarm means, and means for evaluating said computed blood pressure to determine if it falls outside one or more predetermined ranges, and for activating said alarm means when the computed blood pressure falls outside said ranges.

80. The blood pressure monitoring device of claim 62, wherein the means for selectively providing said diagnostically accurate blood pressure measuring device data includes cable input coupling means in said unit to which can be applied a cable carrying said diagnostically accurate blood pressure measuring device data.

81. The blood pressure monitoring device of claim 62, wherein said transducer is adapted to produce output signals representative of the movement of an arterial wall in response to the pumping of blood by the heart.

82. The blood pressure monitoring device of claim 62, wherein said transducer is a piezoelectric transducer.

83. The blood pressure monitoring device of claim 62, wherein said diagnostically accurate blood pressure measuring device is a separate cuff sphygmomanometer.

84. The blood pressure monitoring device of claim 62, wherein said transducer includes strain gauge means.

85. The blood pressure monitoring device of claim 62, wherein said transducer includes an aneroid chamber.

86. The blood pressure monitoring device as claimed in claim 62, wherein

said transducer includes an optical motion sensor.

87. The blood pressure monitoring device of claim 62, wherein said computing means additionally uses data interpretation criteria.