Blood pressure monitoring apparatus

• US 6,083,171 A
• Filed: 11/01/1996
• Issued: 07/04/2000
• Est. Priority Date: 11/02/1995
• Status: Expired due to Term

• Current Assignee: Nihon Kohden Corporation
• Original Assignee: Nihon Kohden Corporation
• Inventors: Kasuya, Hiromitsu, Ono, Kohei, Sugo, Yoshihiro, Hosaka, Hidehiro, Sohma, Takeshi
• Primary Examiner(s): Nasser, Robert L.
• Application Number:
  US08/742,750
• Time in Patent Office: 1,341 Days
• Field of Search: 600/485, 600/490, 600/493-496, 600/500
• US Class Current: 600/494
• CPC Class Codes: A61B 5/022 by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
• CPC Class Codes: A61B 5/0285 Measuring or recording phase velocity of blood waves

Abstract

A pulse wave propagation time is counted constantly. Not only it is judged whether or not a pulse wave propagation time change ΔT exceeds a pulse wave propagation time change threshold ΔTs, but also it is judged whether or not cardiovascular dynamic changes ΔHR, r₁, r₂ exceed thresholds thereof ΔHRs, r₁ s, r₂ s, whereby a sudden turn for the worse in the blood pressure fluctuation of a subject is monitored. If any one of the changes exceeds the threshold thereof, a blood pressure measurement using a cuff 2 is made on the subject.

Claims

1. A blood pressure monitoring apparatus comprising:

blood pressure measuring means for measuring blood pressure using a cuff;

storage means for storing a pulse wave propagation time change threshold and a cardiovascular dynamic change threshold, both thresholds being inputted from an external device;

time interval detection reference point detecting means for detecting a time interval detection reference point on a pulse wave at an aorta of a body;

pulse wave detecting means for detecting a pulse wave at a peripheral blood vessel appearing with a time delay with respect to said pulse wave at said aorta;

pulse wave propagation time counting means for counting a pulse wave propagation time based on detected outputs from said time interval detection reference point detecting means and said pulse wave detecting means;

pulse wave propagation time change calculating means for calculating a pulse wave propagation time change from said two pulse wave propagation times counted by said pulse wave propagation time counting means;

cardiovascular dynamic change calculating means for calculating a cardiovascular dynamic change from said time interval detection reference point or said pulse wave at said peripheral blood vessel;

first judging means for judging whether or not said pulse wave propagation time change calculated by said pulse wave propagation time change calculating means exceeds said pulse wave propagation time change threshold stored in said storage means;

second judging means for judging whether or not said cardiovascular dynamic change calculated by said cardiovascular dynamic change calculating means exceeds said cardiovascular dynamic change threshold stored in said storage means; and

control means for controlling said blood pressure measuring means and for measuring blood pressure of a subject using said cuff if it is judged that said pulse wave propagation time change exceeds said pulse wave propagation time change threshold or if it is judged that said cardiovascular dynamic change exceeds said cardiovascular dynamic change threshold.

2. A blood pressure monitoring apparatus according to claim 1, wherein said storage means stores a cardiovascular dynamic change threshold equivalent to a heart rate change, said cardiovascular dynamic change calculating means calculates a heart rate change based on said time interval detection reference point detected by said time interval detection reference point detecting means, and said second judging means judges whether or not said heart rate change calculated by said cardiovascular dynamic change calculating means exceeds said cardiovascular dynamic change threshold equivalent to said heart rate change stored in said storage means.

3. A blood pressure monitoring apparatus according to claim 1, wherein said storage means stores a cardiovascular dynamic change threshold equivalent to a rate of change of an amplitude of a pulse wave at a peripheral blood vessel;

said cardiovascular dynamic change calculating means calculates said rate of change of said amplitude of said pulse wave, which is a chronological rate of change of said amplitude of said pulse wave based on said pulse wave at said peripheral blood vessel detected by said pulse wave detecting means; and

said second judging means judges whether or not said rate of change of said amplitude of said pulse wave calculated by said cardiovascular dynamic change calculating means exceeds said cardiovascular dynamic change threshold equivalent to said rate of change of said amplitude of said pulse wave of said peripheral blood vessel stored in said storage means.

4. A blood pressure monitoring apparatus according to claim 1, wherein said storage means stores a cardiovascular dynamic change threshold equivalent to a rate of change of a dc component of a pulse wave of a peripheral blood vessel;

said cardiovascular dynamic change calculating means calculates said rate of change of said dc component of said pulse wave, which is a chronological rate of change of said dc component of said pulse wave based on said pulse wave at said peripheral blood vessel detected by said pulse wave detecting means; and

said second judging means judges whether or not said rate of change of said dc component of said pulse wave calculated by said cardiovascular dynamic change calculating means exceeds said cardiovascular dynamic change threshold equivalent to said rate of change of said dc component of said pulse wave of said peripheral blood vessel stored in said storage means.

5. A blood pressure monitoring apparatus according to claim 1, wherein said storage means stores cardiovascular dynamic change thresholds respectively equivalent to a heart rate change, a rate of change of an amplitude of a pulse wave of a peripheral blood vessel, and a rate of change of a dc component of a pulse wave of a peripheral blood vessel;

said cardiovascular dynamic change calculating means calculates not only said heart rate change based on said time interval detection reference point detected by said time interval detection reference point detecting means, but also said rate of change of said amplitude of said pulse wave, which is a chronological rate of change of said amplitude of said pulse wave and said rate of change of said dc component of said pulse wave, which is a chronological rate of change of said dc component of said pulse wave, based on said pulse wave at said peripheral blood vessel detected by said pulse wave detecting means;

said second judging means judges whether or not said heart rate change calculated by said cardiovascular dynamic change calculating means exceeds said cardiovascular dynamic change threshold equivalent to said heart rate change stored in said storage means, whether or not said rate of change of said amplitude of said pulse wave calculated by said cardiovascular dynamic change calculating means exceeds said cardiovascular dynamic change threshold equivalent to said rate of change of said amplitude of said pulse wave of said peripheral blood vessel stored in said storage means, and whether or not said rate of change of said dc component of said pulse wave calculated by said cardiovascular dynamic change calculating means exceeds said cardiovascular dynamic change threshold equivalent to said rate of change of said dc component of said peripheral blood vessel stored in said storage means; and

said control means controls said blood pressure measuring means and measures blood pressure of a subject using said cuff if it is judged that said heart rate change exceeds said cardiovascular dynamic change threshold equivalent to said heart rate change, if it is judged that said rate of change of said amplitude of said pulse wave exceeds said cardiovascular dynamic change threshold equivalent to said rate of change of said amplitude of said pulse wave of said peripheral blood vessel, or if it is judged that said rate of change of said dc component of said pulse wave exceeds said cardiovascular dynamic change threshold equivalent to said rate of change of said dc component of said pulse wave of said peripheral blood vessel.

6. A blood pressure monitoring method comprising said steps of:

measuring blood pressure using cuff;

storing a pulse wave propagation time change threshold and a cardiovascular dynamic change threshold, both thresholds being inputted from an external device;

detecting a time interval detection reference point on a pulse wave at an aorta of a body;

detecting a pulse wave at a peripheral blood vessel appearing with a time delay with respect to said pulse wave at said aorta;

counting a pulse wave propagation time based on detected outputs from said time interval detection reference point and said pulse wave;

calculating a pulse wave propagation time change from said two pulse wave propagation times counted;

calculating a cardiovascular dynamic change from said time interval detection reference point or said pulse wave at said peripheral blood vessel;

judging whether or not said pulse wave propagation time change calculated exceeds said pulse wave propagation time change threshold stored;

judging whether or not said cardiovascular dynamic change exceeds said cardiovascular dynamic change threshold; and

measuring blood pressure of a subject using said cuff if it is judged that said pulse wave propagation time change exceeds said pulse wave propagation time change threshold or if it is judged that said cardiovascular dynamic change exceeds said cardiovascular dynamic change threshold.

7. A blood pressure monitoring apparatus comprising:

blood pressure measuring means for measuring blood pressure using a cuff;

storage means for storing a pulse wave propagation time change threshold and a cardiovascular dynamic change threshold, both thresholds being inputted from an external device;

time interval detection reference point detecting means for detecting a time interval detection reference point on a pulse wave at an aorta of a body;

pulse wave detecting means for detecting a pulse wave at a peripheral blood vessel appearing with a time delay with respect to said pulse wave at said aorta;

pulse wave propagation time counting means for counting a pulse wave propagation time based on detected outputs from said time interval detection reference point detecting means and said pulse wave detecting means;

pulse wave propagation time change calculating means for calculating a pulse wave propagation time change from said two pulse wave propagation times counted by said pulse wave propagation time counting means;

main judgement means for judging whether or not a condition of an subject is changed on the basis of a result of said pulse wave propagation time change calculating means;

cardiovascular dynamic change calculating means for calculating a cardiovascular dynamic change from said time interval detection reference point or said pulse wave at said peripheral blood vessel;

auxiliary judging means for judging whether or not said cardiovascular dynamic change calculated by said cardiovascular dynamic change calculating means exceeds said cardiovascular dynamic change threshold stored in said storage means,

main control means for controlling said blood pressure measuring means and for measuring blood pressure of a subject using said cuff in accordance with a result of said main judging means and auxiliary judging means;

wherein said main judging means for judging whether or not said pulse wave propagation time change calculated by said pulse wave propagation time change calculating means exceeds said pulse wave propagation time change threshold stored in said storage means, and said main control means for controlling said blood pressure measuring means and for measuring blood pressure of a subject using said cuff if it is judged that said pulse wave propagation time change exceeds said pulse wave propagation time change threshold or if it is judged that said cardiovascular dynamic change exceeds said cardiovascular dynamic change threshold.

8. A blood pressure monitoring apparatus according to claim 7, wherein said storage means stores a cardiovascular dynamic change threshold equivalent to a heart rate change, said cardiovascular dynamic change calculating means calculates a heart rate change based on said time interval detection reference point detected by said time interval detection reference point detecting means, and said second judging means judges whether or not said heart rate change calculated by said cardiovascular dynamic change calculating means exceeds said cardiovascular dynamic change threshold equivalent to said heart rate change stored in said storage means.

9. A blood pressure monitoring apparatus according to claim 7, wherein said storage means stores a cardiovascular dynamic change threshold equivalent to a rate of change of an amplitude of a pulse wave at a peripheral blood vessel;

said cardiovascular dynamic change calculating means calculates said rate of change of said amplitude of said pulse wave, which is a chronological rate of change of said amplitude of said pulse wave based on said pulse wave at said peripheral blood vessel detected by said pulse wave detecting means; and

said second judging means judges whether or not said rate of change of said amplitude of said pulse wave calculated by said cardiovascular dynamic change calculating means exceeds said cardiovascular dynamic change threshold equivalent to said rate of change of said amplitude of said pulse wave of said peripheral blood vessel stored in said storage means.

10. A blood pressure monitoring apparatus according to claim 7, wherein said storage means stores a cardiovascular dynamic change threshold equivalent to a rate of change of a dc component of a pulse wave of a peripheral blood vessel;

said cardiovascular dynamic change calculating means calculates said rate of change of said dc component of said pulse wave, which is a chronological rate of change of said dc component of said pulse wave based on said pulse wave at said peripheral blood vessel detected by said pulse wave detecting means; and

said second judging means judges whether or not said rate of change of said dc component of said pulse wave calculated by said cardiovascular dynamic change calculating means exceeds said cardiovascular dynamic change threshold equivalent to said rate of change of said dc component of said pulse wave of said peripheral blood vessel stored in said storage means.

11. A blood pressure monitoring apparatus according to claim 7, wherein said storage means stores cardiovascular dynamic change thresholds respectively equivalent to a heart rate change, a rate of change of an amplitude of a pulse wave of a peripheral blood vessel, and a rate of change of a dc component of a pulse wave of a peripheral blood vessel;

said cardiovascular dynamic change calculating means calculates not only said heart rate change based on said time interval detection reference point detected by said time interval detection reference point detecting means, but also said rate of change of said amplitude of said pulse wave, which is a chronological rate of change of said amplitude of said pulse wave and said rate of change of said dc component of said pulse wave, which is a chronological rate of change of said dc component of said pulse wave, based on said pulse wave at said peripheral blood vessel detected by said pulse wave detecting means;

said second judging means judges whether or not said heart rate change calculated by said cardiovascular dynamic change calculating means exceeds said cardiovascular dynamic change threshold equivalent to said heart rate change stored in said storage means, whether or not said rate of change of said amplitude of said pulse wave calculated by said cardiovascular dynamic change calculating means exceeds said cardiovascular dynamic change threshold equivalent to said rate of change of said amplitude of said pulse wave of said peripheral blood vessel stored in said storage means, and whether or not said rate of change of said dc component of said pulse wave calculated by said cardiovascular dynamic change calculating means exceeds said cardiovascular dynamic change threshold equivalent to said rate of change of said dc component of said peripheral blood vessel stored in said storage means; and

said control means controls said blood pressure measuring means and measures blood pressure of a subject using said cuff if it is judged that said heart rate change exceeds said cardiovascular dynamic change threshold equivalent to said heart rate change, if it is judged that said rate of change of said amplitude of said pulse wave exceeds said cardiovascular dynamic change threshold equivalent to said rate of change of said amplitude of said pulse wave of said peripheral blood vessel, or if it is judged that said rate of change of said dc component of said pulse wave exceeds said cardiovascular dynamic change threshold equivalent to said rate of change of said dc component of said pulse wave of said peripheral blood vessel.

12. A blood pressure monitoring method comprising said steps of:

storing a pulse wave propagation time change threshold and a cardiovascular dynamic change threshold, both thresholds being inputted from an external means;

detecting a time interval detection reference point on a pulse wave at an aorta of a body;

detecting a pulse wave at a peripheral blood vessel appearing with a time delay with respect to said pulse wave at said aorta;

counting a pulse wave propagation time based on detected outputs from said time interval detection reference point and said pulse wave;

calculating a pulse wave propagation time change from said two pulse wave propagation times counted;

calculating a cardiovascular dynamic change from said time interval detection reference point or said pulse wave at said peripheral blood pressure;

judging whether or not said pulse wave propagation time change calculated exceeds said pulse wave propagation time change threshold stored;

judging whether or not said cardiovascular dynamic change exceeds said cardiovascular dynamic change threshold; and

measuring blood pressure of a subject using said cuff if it is judges that said pulse wave propagation time change exceeds said pulse wave propagation time change threshold or if it is judged that said cardiovascular dynamic change exceeds said cardiovascular dynamic change threshold.

13. A blood pressure monitoring apparatus comprising:

blood pressure measuring means for measuring blood pressure using a cuff;

time interval detection reference point detecting means for detecting a time interval detection reference point for counting pulse wave propagation time;

pulse wave detection means for detecting a pulse wave at a peripheral blood vessel appearing with a time delay with respect to said pulse wave at an aorta;

pulse wave propagation time counting means for counting a pulse wave propagation time based on detected outputs from said time interval detection reference point detecting means and said pulse wave detecting means;

cardiovascular dynamic change calculating means for calculating a cardiovascular dynamic change from said time interval detection reference point or said pulse wave at said peripheral blood vessel;

control means for controlling said blood pressure measurement means on the basis of the change of pulse wave propagation time, counted by said pulse wave propagation time counting means and the cardiovascular dynamic change calculated by said cardiovascular dynamic change calculating means so that the blood pressure of a subject is measured using the cuff.

14. The blood pressure monitoring apparatus according to claim 13, wherein said cardiovascular dynamic change is equivalent to at least one of a heart rate change, change of amplitude of the pulse wave of said peripheral blood vessel, and change of dc component of the pulse wave of said peripheral blood vessel.

15. The blood pressure measuring apparatus according to claim 13, wherein said time interval detection reference point detection means includes an electrode to be attached to a subject, and determines an electrocardiographic R wave as the time interval detection reference point.

16. A blood pressure monitoring apparatus comprising:

blood pressure measuring means for measuring blood pressure using a cuff;

time interval detection reference point detecting means for detecting a time interval detection reference point for counting pulse wave propagation time;

pulse wave detection means for detecting a pulse wave at a peripheral blood vessel appearing with a time delay with respect to said pulse wave at an aorta;

pulse wave propagation time counting means for counting a pulse wave propagation time based on detected outputs from said time interval detection reference point detecting means and said pulse wave detecting means;

cardiovascular dynamic change calculating means for calculating a cardiovascular dynamic change from said time interval detection reference point or said pulse wave at said peripheral blood vessel;

first judging means for judging whether or not change of pulse wave propagation time counted by said pulse wave propagation time counting means exceeds a first predetermined threshold;

second judging means for judging whether or not said cardiovascular dynamic change calculated by said cardiovascular dynamic change calculating means exceeds a second predetermined threshold; and

control means for controlling said blood pressure measuring means and for measuring blood pressure of a subject using said cuff under at least one of condition that said first judging means judges that the change of pulse wave propagation time counted by said pulse wave propagation time counting means exceeds the first predetermined threshold and the condition that said second judging means judges that said cardiovascular dynamic change calculated by said cardiovascular dynamic change calculating means exceeds the second predetermined threshold.

17. The blood pressure monitoring apparatus according to claim 16, wherein said cardiovascular dynamic change is equivalent to at least one of a heart rate change, change of amplitude of the pulse wave of said peripheral blood vessel, and change of dc component of the pulse wave of said peripheral blood vessel.

18. The blood pressure monitoring apparatus according to claim 16, wherein said cardiovascular dynamic change calculating means calculates heart rate changes based on said time interval detection reference point by said time interval detection reference point detecting means;

and wherein said second judging means judges whether or not said heart rate change calculated by said cardiovascular dynamic change calculating means exceeds said second predetermined threshold which is equivalent to heart rate change.

19. The blood pressure monitoring apparatus according to claim 16, wherein said cardiovascular dynamic change calculating means calculates a change of amplitude of said pulse wave at said peripheral blood vessel detected by said pulse wave detecting means;

and wherein said second judging means judges whether or not said changes of amplitude of said pulse wave calculated by said cardiovascular dynamic change calculating means exceeds said second predetermined threshold which is equivalent to changes of amplitude of the pulse wave of said peripheral blood vessel.

20. The blood pressure monitoring apparatus according to claim 16, wherein said cardiovascular dynamic change calculating means calculates a change of dc component of said pulse wave at said peripheral blood vessel detected by said pulse wave detecting means;

and wherein said second judging means judges whether or not said changes of dc component of said pulse wave calculated by said cardiovascular dynamic change calculating means exceeds said second predetermined threshold which is equivalent to changes of dc component of the pulse wave of said peripheral blood vessel.

21. The blood pressure measuring apparatus according to claim 16, wherein said time interval detection reference point detection means includes an electrode to be attached to a subject and determines an electrocardiographic R wave as the time interval detection reference point.

22. A blood pressure monitoring apparatus comprising:

blood pressure measuring means for measuring blood pressure using a cuff;

time interval detection reference point detecting means for detecting a time interval detection reference point for counting a pulse wave propagation time;

pulse wave detection means for detecting a pulse wave at a peripheral blood vessel appearing with a time delay with respect to said pulse wave at an aorta;

pulse wave propagation time counting means for counting a pulse wave propagation time based on detected outputs from said time interval detection reference point detecting means and said pulse wave detecting means;

main judgement means for judging whether or not a condition of a subject is changed on the basis of change of pulse wave propagation time counted by said pulse wave propagation time counting means;

cardiovascular dynamic change calculating means for calculating a cardiovascular dynamic change from said time interval detection reference point or said pulse wave at said peripheral blood vessel;

auxiliary judging means for judging whether or not said cardiovascular dynamic change calculated by said cardiovascular dynamic change calculating means exceeds a second predetermined threshold;

main control means for controlling said blood pressure measuring means and for measuring blood pressure of a subject using said cuff in accordance with a result of said main judging means and auxiliary judging means;

wherein said main judging means judges whether or not the change of pulse wave propagation time calculated by said pulse wave propagation time counting means exceeds a first predetermined threshold, and wherein said main control means controls said blood pressure measuring and measures blood pressure of a subject using said cuff under at least one condition selected from the condition that it is judged that said change of amount relating to pulse wave propagation time exceeds the first predetermined threshold and the condition that it is judged that said cardiovascular dynamic change exceeds the second predetermined threshold.

23. The blood pressure monitoring apparatus according to claim 22, wherein said cardiovascular dynamic change is equivalent to at least one of a heart rate change, change of amplitude of the pulse wave of said peripheral blood vessel, and change of dc component of the pulse wave of said peripheral blood vessel.

24. The blood pressure monitoring apparatus according to claim 22, wherein said cardiovascular dynamic change calculating means calculates heart rate changes based on said time interval detection reference point detected by said time interval detection reference point detecting means, and wherein said auxiliary judging means judges whether or not said heart rate change calculated by said cardiovascular dynamic change calculating means exceeds said second predetermined threshold which is equivalent to heart rate change.

25. The blood pressure monitoring apparatus according to claim 22, wherein said cardiovascular dynamic change calculating means calculates a change of amplitude of said pulse wave at said peripheral blood vessel detected by said pulse wave detecting means;

and wherein said auxiliary judging means judges whether or not said changes of amplitude of said pulse wave calculated by said cardiovascular dynamic change calculating means exceeds second predetermined threshold which is equivalent to changes of amplitude of the pulse wave of said peripheral blood vessel.

26. The blood pressure monitoring apparatus according to claim 22, wherein said cardiovascular dynamic change calculating means calculates a change of dc component of said pulse wave at said peripheral blood vessel detected by said pulse wave detecting means;

and wherein said auxiliary judging means judges whether or not said changes of dc component of said pulse wave calculated by said cardiovascular dynamic change calculating means exceeds said second predetermined threshold which is equivalent to changes of dc component of the pulse wave of said peripheral blood vessel.

27. The blood pressure measuring apparatus according to claim 22, wherein said time interval detection reference point detection means includes an electrode to be attached to a subject, and determines an electrocardiographic R wave as the time interval detection reference point.

28. A blood pressure monitoring apparatus comprising:

blood pressure measuring means for measuring blood pressure using a cuff;

pulse wave propagation time measurement means for measuring pulse wave propagation time;

cardiovascular dynamic change calculating means for calculating a cardiovascular dynamic change;

control means for controlling said blood pressure measuring means on the basis of a change of pulse wave propagation time measured by said pulse wave propagation time measurement means and the cardiovascular dynamic change calculated by said cardiovascular dynamic change calculating means, so that the blood pressure of a subject is measured using the cuff.

29. The blood pressure monitoring apparatus according to claim 28, wherein said cardiovascular dynamic change is equivalent to at least one of a heart rate change, change of amplitude of a pulse wave, and change of dc component of a pulse wave.

30. The blood pressure measuring apparatus according to claim 28, wherein said pulse wave propagation time measurement means includes time interval detection reference point detection means having an electrode to be attached to a subject, and determines an electrocardiographic R wave as a time interval reference point.