Noninvasive blood pressure measuring device and method

• US 5,772,602 A
• Filed: 11/13/1996
• Issued: 06/30/1998
• Est. Priority Date: 11/14/1995
• Status: Expired due to Fees

• Current Assignee: Nihon Kohden Corporation
• Original Assignee: Nihon Kohden Corporation
• Inventors: Kaji, Toshichika, Sakai, Yoshio
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US08/747,896
• Time in Patent Office: 594 Days
• Field of Search: 128/672, 128/680, 128/681, 128/682, 128/687, 600/485, 600/493, 600/494, 600/495, 600/500
• US Class Current: 600/495
• CPC Class Codes: A61B 5/022 by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
• CPC Class Codes: A61B 5/025 within occluders, e.g. responsive to Korotkoff sounds electric stethoscopes A61B7/04

Abstract

A CPU 9 controls an air supplying/discharging device to set a pressure of air within a-cuff to 60 mmHg for 60 seconds before making a blood pressure measurement, detects pulse waves of the cuff pressure for such period of time, and calculates a degree of stability of the detected pulse waves. When a blood pressure measurement is made, the CPU reduces the cuff pressure by a step pressure reducing operation whose step duration corresponds to the calculated degree of stability.

Claims

1. A noninvasive blood pressure measuring device comprising:

a cuff for measuring blood pressure based on a pressure of gas within said cuff, said cuff to be wrapped around a body;

gas supplying/discharging means for supplying and discharging said gas within respect to said cuff;

first cuff pressure control means for controlling said gas supplying/discharging means so that said pressure of said gas within said cuff reaches a first pressure;

pulse wave detecting means for detecting a pulse wave in said pressure while said pressure of said gas within said cuff is maintained at said first pressure;

stability detecting means for detecting a degree of stability of said pulse wave;

pressure reducing means for performing a predetermined step pressure reducing operation, selected from a plurality of predetermined step pressure reducing operations, to said gas within said cuff;

judging means for selecting said predetermined step pressure reducing operation from said plurality of predetermined step pressure reducing operations in accordance with said degree of stability of said pulse wave detected by said stability detecting means;

second cuff pressure control means for controlling said gas supplying/discharging means to increase said pressure of said gas within said cuff to a second pressure, and for performing said predetermined s pressure reducing operation, selected by said judging means, to said pressure of said gas within said cuff; and

blood pressure value determining means for detecting a pulse wave in said pressure while said predetermined step pressure reducing operation is performed to said pressure of said gas within said cuff by said second cuff pressure control means for determining a blood pressure value based on said pulse wave.

2. The noninvasive blood pressure measuring device according to claim 1, wherein said pulse wave detecting means comprises:

light emitting means for irradiating a living tissue; and

light receiving means for receiving light irradiated from said light emitting means and for obtaining an electrical signal of a pulse wave.

3. A noninvasive blood pressure measuring device comprising:

a cuff for measuring blood pressure based on a pressure of gas within said cuff, said cuff to be wrapped around a body;

gas supplying/discharging means for supplying and discharging said gas within respect to said cuff;

first cuff pressure control means for controlling said gas supplying/discharging means so that said pressure of said gas within said cuff reaches a first pressure;

pulse wave detecting means for detecting a pulse wave in said pressure while said pressure of said gas within said cuff is maintained at said first pressure;

stability detecting means for detecting a degree of stability of said pulse wave;

pressure reducing means for performing a first predetermined step pressure reducing operation, selected from a plurality of predetermined step pressure reducing operations, to said gas within said cuff;

judging means for selecting said first predetermined step pressure reducing operation from said plurality of predetermined step pressure reducing operations in accordance with said degree of stability detected by said stability detecting means;

stability analyzing means for analyzing a degree of stability of said pulse wave detected by said pulse wave detecting means while any one of said plurality of predetermined step pressure reducing operations is performed, and for selecting a second predetermined step pressure reducing operation from said plurality of predetermined s pressure reducing operations based on an analyzed degree of stability;

second cuff pressure control means for controlling said gas supplying/discharging means to increase said pressure of said gas within said cuff to a second pressure, for performing said first predetermined step pressure reducing operation selected by said judging means to said pressure of said gas within said cuff and for controlling said gas supplying/discharging means so that said second predetermined step pressure reducing operation selected by said stability analyzing means is performed to said pressure of said gas within said cuff thereafter; and

blood pressure value determining means for detecting a pulse wave in said pressure while said first and second predetermined step pressure reducing operations are performed to said pressure of said gas within said cuff by said second cuff pressure control means for determining a blood pressure value based on said pulse wave.

4. The noninvasive blood pressure measuring device according to claim 3, wherein said pulse wave detecting means comprises:

light emitting means for irradiating a living tissue; and

light receiving means for receiving light irradiated from said light emitting means and for obtaining an electrical signal of a pulse wave.

5. A noninvasive blood pressure method comprising the steps of:

supplying gas to a cuff so that a pressure of said gas within said cuff reaches a first pressure;

detecting a pulse wave in said pressure while said pressure of said gas within said cuff is maintained at said first pressure;

detecting a degree of stability of said pulse wave;

selecting a predetermined step pressure reducing operation from a plurality of predetermined step pressure reducing operations in accordance with said degree of stability;

increasing said pressure of said gas in said cuff to a second pressure;

performing said predetermined step pressure reducing operation;

detecting a pulse wave in said pressure while said predetermined step pressure reducing operation is performed to said pressure of said gas within said cuff; and

determining a blood pressure value based on said pulse wave.

6. A noninvasive blood pressure method comprising the steps of:

supplying gas to a cuff so that a pressure of said gas within said cuff reaches a first pressure;

detecting a pulse wave in said pressure while said pressure of said gas within said cuff is maintained at said first pressure;

detecting a degree of stability of said pulse wave;

selecting a first predetermined step pressure reducing operation from a plurality of predetermined step pressure reducing operations in accordance with said degree of stability;

analyzing a degree of stability of a pulse wave in said pressure of said gas within said cuff while any one of said plurality of predetermined step pressure reducing operations is performed, and for selecting a second predetermined step pressure reducing operation from said plurality of predetermined step pressure reducing operations based on an analyzed degree of stability;

increasing said pressure of said gas in said cuff to a second pressure;

performing said first predetermined pressure reducing operation to said pressure of said gas within said cuff;

performing said second predetermined step pressure reducing operation to said pressure of said gas within said cuff thereafter;

detecting a pulse wave in said pressure while said first and second predetermined step pressure reducing operations are performed to said pressure of said gas within said cuff; and

determining a blood pressure value based on said pulse wave.

7. A noninvasive blood pressure measuring device comprising:

a cuff;

to be wrapped around a body, for measuring blood pressure based on a pressure of gas within said cuff;

gas supplying/discharging means for supplying and discharging said gas with respect to said cuff;

first cuff pressure control means for controlling said gas supplying/discharging means so that said pressure of said gas within said cuff reaches a first pressure;

pulse wave detecting means for detecting a pulse wave in said pressure while said pressure of said gas within said cuff is maintained at said first pressure by said first cuff pressure control means;

stability detecting means for detecting a degree of stability of said pulse wave;

pressure reducing means for performing a predetermined continuous pressure reducing operation, selected from a plurality of predetermined continuous pressure reducing operations, to said gas within said cuff;

judging means for selecting said predetermined continuous pressure reducing operation from said plurality of predetermined continuous pressure reducing operations in accordance with said degree of stability of said pulse wave detected by said stability detecting means;

second cuff pressure control means for controlling sad gas supplying/discharging means to increase said pressure of said gas within said cuff to a second pressure, and for performing said predetermined continuous pressure reducing operation, selected by said judging means, to said pressure of said gas within said cuff; and

blood pressure value determining means for detecting a pulse wave in said pressure while said predetermined continuous pressure reducing operation is performed to said pressure of said gas within said cuff, by said second cuff pressure control means, for determining a blood pressure value based on a detected pulse wave.

8. The noninvasive blood pressure measuring device according to claim 7, wherein a pressure reducing speed of said predetermined continuous pressure reducing operation is slow when said stability of said pulse wave is low.

9. The noninvasive blood pressure measuring device according to claim 7, wherein said pulse wave detecting means comprises:

light emitting means for irradiating a living tissue; and

light receiving means for receiving light irradiated from said light emitting means and for obtaining an electrical signal of pulse wave.

10. A noninvasive blood pressure measuring device comprising:

a cuff, to be wrapped around a body, for measuring blood pressure based on a pressure of gas within said cuff;

gas supplying/discharging means for supplying and discharging said gas with respect to said cuff;

first cuff pressure control means for controlling said gas supplying/discharging means so that said pressure of said gas within said cuff reaches a first pressure;

pulse wave detecting means for detecting a pulse wave in said pressure while said pressure of said gas within said cuff is maintained at said first pressure by said first cuff pressure control means;

stability detecting means for detecting a degree of stability of said pulse wave;

pressure reducing means for performing a first predetermined continuous pressure reducing operation, selected from a plurality of predetermined continuous pressure reducing operations, to said gas within said cuff;

judging means for selecting said first predetermined continuous pressure reducing operation from said plurality of predetermined continuous pressure reducing operations in accordance with said degree of stability of said pulse wave detected by said stability detecting means;

stability analyzing means for analyzing a degree of stability of said pulse wave detected by said pulse wave detecting means while any one of said plurality of predetermined continuous pressure reducing operations from said plurality of predetermined continuous pressure reducing operations is performed based on said degree of stability; and

for selecting a second predetermined continuous pressure reducing operation based on an analyzed degree of stability;

second cuff pressure control means for controlling said gas supplying/discharging means so that after said pressure of said gas within said cuff has increased to a second pressure, said first predetermined continuous pressure reducing operation, selected by said judging means, is performed, and for controlling said gas supplying/discharging means so that said second predetermined continuous pressure reducing operation selected by said stability analyzing means is performed to said pressure of said gas within said cuff thereafter; and

blood pressure value determining means for detecting a pulse wave in said pressure while said first and second predetermined continuous pressure reducing operations are performed to said pressure of said gas within said cuff, by said second cuff pressure control means, for determining a blood pressure value based on said pulse wave.

11. The noninvasive blood pressure measuring device according to claim 10, wherein a pressure reducing speed of said predetermined continuous pressure reducing operation is slow when said stability of said pulse wave is low.

12. The noninvasive blood pressure measuring device according to claim 10, wherein said pulse wave detecting means comprises:

light emitting means for irradiating a living tissue; and

light receiving means for receiving light irradiated from said light emitting means and for obtaining an electrical signal of pulse wave.

13. A noninvasive blood pressure method comprising the steps of:

supplying gas to a cuff so that said cuff reaches a first pressure;

detecting a pulse wave of said pressure while said pressure of said gas within said cuff is maintained at said first pressure;

detecting a degree of stability of said pulse wave;

selecting a predetermined continuous pressure reducing operation, from a plurality of predetermined continuous pressure reducing operations, in accordance with said degree of stability;

increasing said pressure of said gas in said cuff to a second pressure;

performing said predetermined continuous pressure reducing operation, selected by said judging means, after said second pressure is reached;

detecting a pulse wave in said pressure while said predetermined continuous pressure reducing operation is performed; and

determining a blood pressure value based on said pulse wave detected in said pressure.

14. The noninvasive blood pressure method according to claim 13, wherein a pressure reducing speed of said predetermined continuous pressure reducing operation is slow when the stability of said pulse wave is low.

15. A noninvasive blood pressure method comprising the steps of:

supplying gas to a cuff so that said cuff reaches a first pressure;

detecting a pulse wave in said pressure while said pressure of said gas within said cuff is maintained at said first pressure;

detecting a degree of stability of said pulse wave;

selecting a first predetermined continuous pressure reducing operation from a plurality of predetermined continuous pressure reducing operations in accordance with said degree of stability;

analyzing a degree of stability of a pulse wave detected by using said pulse wave detecting means while any one of said plurality of predetermined continuous pressure reducing operations is performed;

selecting a second predetermined continuous pressure reducing operation from said plurality of predetermined continuous pressure reducing operations based on an analyzed degree of stability;

increasing said pressure in said cuff to a second pressure;

performing said first predetermined continuous pressure reducing operation;

performing said second predetermined continuous pressure reducing operation;

detecting a pulse wave in said pressure while said first and second predetermined continuous pressure reducing operations are performed to said pressure of said gas within said cuff; and

determining a blood pressure value based on said pulse wave.

16. The noninvasive blood pressure method according to claim 15, wherein a pressure reducing speed of said predetermined continuous pressure reducing operation is slow when the stability of said pulse wave is low.

17. A noninvasive blood pressure measuring device comprising:

a cuff, to be wrapped around a body, for measuring blood pressure based on a pressure of gas within said cuff;

gas supplying/discharging means for supplying and discharging said gas with respect to said cuff;

first cuff pressure control means for controlling said gas supplying/discharging means so that said pressure of said gas within said cuff reaches a predetermined pressure;

pulse wave detecting means for detecting a pulse wave in said gas while said pressure of said gas within said cuff is maintained at said predetermined pressure;

stability detecting means for detecting a degree of stability of said pulse wave;

pressure reducing means for performing a predetermined step pressure reducing operation, selected from a plurality of predetermined step pressure reducing operations, to said gas within said cuff;

judging means for selecting said predetermined step pressure reducing operation from said plurality of predetermined step pressure reducing operations in accordance with said degree of stability of said pulse wave detected by said stability detecting means;

second cuff pressure control means for controlling said gas supplying/discharging means so that said predetermined step pressure reducing operation, selected by said judging means, is performed to said pressure of said gas within said cuff; and

blood pressure value determining means for detecting a pulse wave in said pressure while said predetermined step pressure reducing operation is performed to said pressure of said gas within said cuff, by said second cuff pressure control means, for determining a blood pressure value based on a detected pulse wave.

18. The noninvasive blood pressure measuring device according to claim 17, wherein said pulse wave detecting means comprises:

light emitting means for irradiating a living tissue; and

light receiving means for receiving light irradiated from said light emitting means and for obtaining an electrical signal of a pulse wave.

19. A noninvasive blood pressure measuring device comprising:

a cuff, to be wrapped around a body, for measuring blood pressure based on a pressure of gas within said cuff;

gas supplying/discharging means for supplying and discharging said gas with respect to said cuff;

first cuff pressure control means for controlling said gas supplying/discharging means so that said pressure of said gas within said cuff reaches a first pressure;

pulse wave detecting means for detecting a pulse wave in said pressure while said pressure of said gas within said cuff is maintained at said first pressure;

stability detecting means for detecting a degree of stability of said detected pulse wave;

pressure reducing means for performing a first predetermined step pressure reducing operation, selected from a plurality of predetermined step pressure reducing operations, to said gas within said cuff;

judging means for selecting said first predetermined step pressure reducing operation from said plurality of predetermined step pressure reducing operations in accordance with said degree of stability of said pulse wave detected by said stability detecting means;

stability analyzing means for analyzing a degree of stability of a pulse wave detected by pulse wave detecting means while any one of said plurality of predetermined step pressure reducing operations, from said plurality of predetermined step pressure reducing operations, based on said degree of stability, and for selecting a second predetermined step pressure reducing operation based on an analyzed degree of stability;

second cuff pressure control means for controlling said gas supplying/discharging means so that said first predetermined step pressure reducing operation, selected by said judging means, is performed to said pressure of said gas within said cuff and for controlling said gas supplying/discharging means so that said second predetermined step pressure reducing operation selected by said stability analyzing means is performed to said pressure of said gas within said cuff thereafter; and

blood pressure value determining means for detecting a pulse wave in said pressure while said first and second predetermined step pressure reducing operations are performed to said pressure of said gas within said cuff by said second cuff pressure control means for determining a blood pressure value based on said pulse wave.

20. The noninvasive blood pressure measuring device according to claim 19, wherein said pulse wave detecting means comprises:

light emitting means for irradiating a living tissue; and

light receiving means for receiving light irradiated from said light emitting means and for obtaining an electrical signal of a pulse wave.

21. A noninvasive blood pressure measuring device comprising:

a cuff, to be wrapped around a body, for measuring blood pressure based on a pressure of gas within said cuff;

gas supplying/discharging means for supplying and discharging said gas with respect to said cuff;

first cuff pressure control means for controlling said gas supplying/discharging means so that said pressure of said gas within said cuff reaches a first predetermined pressure;

pulse wave detecting means for detecting a pulse wave while said pressure of said gas within said cuff is maintained at said first predetermined pressure;

stability detecting means for detecting a degree of stability of said pulse wave;

pressure reducing means for performing a predetermined continuous pressure reducing operation, selected from a plurality of predetermined continuous pressure reducing operations, to said gas within said cuff;

judging means for selecting said predetermined continuous pressure reducing operation from said plurality of predetermined continuous pressure reducing operations in accordance with said degree of stability of said pulse wave detected by said stability detecting means;

second cuff pressure control means for controlling said gas supplying/discharging means so that said predetermined continuous pressure reducing operation, selected by said judging means, is performed to said pressure of said gas within said cuff; and

blood pressure value determining means for detecting a pulse wave in said pressure while said predetermined continuous pressure reducing operation is performed to said pressure of said gas within said cuff, by said second cuff pressure control means, for determining a blood pressure value based on said pulse wave.

22. The noninvasive blood pressure measuring device according to claim 21, wherein a pressure reducing speed of said predetermined continuous pressure reducing operation is slow when said stability of said pulse wave is low.

23. The noninvasive blood pressure measuring device according to claim 21, wherein said pulse wave detecting means comprises:

light emitting means for irradiating a living tissue; and

light receiving means for receiving light irradiated from said light emitting means and for obtaining an electrical signal of a pulse wave.

24. A noninvasive blood pressure measuring device comprising:

a cuff to be wrapped around a body, for measuring blood pressure based on a pressure of gas within said cuff;

gas supplying/discharging means for supplying and discharging said gas with respect to said cuff;

first cuff pressure control means for controlling said gas supplying/discharging means so that said pressure of said gas within said cuff reaches a first predetermined pressure;

pulse wave detecting means for detecting a pulse wave while said pressure of said gas within said cuff is maintained at said first predetermined pressure;

stability detecting means for detecting a degree of stability of said pulse wave;

judging means for selecting a first predetermined continuous pressure reducing operation from a plurality of predetermined continuous pressure reducing operations in accordance with said degree of stability of said pulse wave detected by said stability detecting means;

pressure reducing means for performing said first predetermined continuous pressure reducing operation, selected from said plurality of predetermined continuous pressure reducing operations, to said gas within said cuff;

stability analyzing means for analyzing a degree of stability of a pulse wave detected by using said pulse wave detecting means while any one of said plurality of predetermined continuous pressure reducing operations is performed based on said degree of stability, and for selecting a second predetermined continuous pressure reducing operation based upon an analyzed degree of stability;

second cuff pressure control means for controlling said gas supplying/discharging means so that said first predetermined continuous pressure reducing operation, selected by said judging means, is performed to said pressure of said gas within said cuff, and for controlling said gas supplying/discharging means so that said second predetermined continuous pressure reducing operation selected by said stability analyzing means is performed to said pressure of said gas within said cuff thereafter; and

blood pressure value determining means for detecting a pulse wave in said pressure while said first and second predetermined continuous pressure reducing operations are performed to said pressure of said gas within said cuff by said second cuff pressure control means for determining a blood pressure value based on said pulse wave.

25. The noninvasive blood pressure measuring device according to claim 24, wherein a pressure reducing speed of said predetermined continuous pressure reducing operation is slow when said stability of said pulse wave is low.

26. The noninvasive blood pressure measuring device according to claim 24, wherein said pulse wave detecting means comprises:

light emitting means for irradiating a living tissue; and

light receiving means for receiving light irradiated from said light emitting means and for obtaining an electrical signal of a pulse wave.

27. A noninvasive blood pressure method comprising the steps of:

supplying gas to a cuff so that said cuff reaches a predetermined pressure;

detecting a pulse wave in a pressure of said gas in said cuff while said pressure of said gas within said cuff is maintained at said predetermined pressure;

detecting a degree of stability of said pulse wave;

selecting a predetermined step pressure reducing operation from a plurality of predetermined step pressure reducing operations in accordance with a detected degree of stability;

controlling said gas supplying/discharging means so that said predetermined step pressure reducing operation, selected by said judging means, is performed to said pressure of said gas within said cuff;

detecting a pulse wave in said pressure while said predetermined step pressure reducing operation is performed to said pressure of said gas within said cuff; and

determining a blood pressure value based on said pulse wave detected in said pressure.

28. A noninvasive blood pressure method comprising the steps of:

supplying gas to a cuff so that said cuff reaches a predetermined pressure;

detecting a pulse wave of a pressure of said gas while said pressure of said gas within said cuff is maintained at said predetermined pressure;

detecting a degree of stability of said pulse wave;

selecting a first predetermined step pressure reducing operation from a plurality of predetermined step pressure reducing operations in accordance with a detected degree of stability;

analyzing a degree of stability of a pulse wave detected by using said pulse wave detecting means while any one of said plurality of predetermined step pressure reducing operations is performed, and for selecting a second predetermined step pressure reducing operation from said plurality of predetermined step pressure reducing operations based on an analyzed degree of stability;

performing said first predetermined step pressure reducing operation;

performing said second predetermined step pressure reducing operation to said pressure of said gas within said cuff;

detecting a pulse wave in said pressure while said first and second predetermined step pressure reducing operations are performed to said pressure of said gas within said cuff; and

determining a blood pressure value based on said pulse wave detected in said pressure.

29. A noninvasive blood pressure method comprising the steps of:

supplying gas to a cuff so that said cuff reaches a predetermined pressure;

detecting a pulse wave in a pressure of said gas while said pressure of said gas within said cuff is maintained at said predetermined pressure;

detecting a degree of stability of said pulse wave;

selecting a predetermined continuous pressure reducing operation from a plurality of predetermined continuous pressure reducing operations in accordance with a detected degree of stability;

performing said predetermined continuous pressure reducing operation of said pressure of said gas within said cuff;

detecting a pulse wave in said pressure while said predetermined continuous pressure reducing operation is performed; and

determining a blood pressure value based on said pulse wave detected in said pressure.

30. The noninvasive blood pressure method according to claim 29, wherein a pressure reducing speed of said predetermined continuous pressure reducing operation is slow when said stability of said pulse wave is low.

31. A noninvasive blood pressure method comprising the steps of:

supplying gas to a cuff so that said cuff reaches a predetermined pressure;

detecting a pulse wave of a pressure of said gas while said pressure of said gas within said cuff is maintained at said predetermined pressure;

detecting a degree of stability of said pulse wave;

selecting a first predetermined continuous pressure reducing operation from a plurality of predetermined continuous pressure reducing operations in accordance with a detected degree of stability;

analyzing a degree of stability of a pulse wave detected by using said pulse wave detecting means while any one of said plurality of predetermined continuous pressure reducing operations is performed, and for selecting a second predetermined continuous pressure reducing operation from said plurality of predetermined continuous pressure reducing operations based on an analyzed degree of stability;

performing said first predetermined continuous pressure reducing operations;

performing said second predetermined continuous pressure reducing operation of said gas within said cuff;

detecting a pulse wave in said pressure while said first and second predetermined continuous pressure reducing operations are performed to said pressure of said gas within said cuff; and

determining a blood pressure value based on said pulse wave detected in said pressure.

32. The noninvasive blood pressure method according to claim 31, wherein a pressure reducing speed of said predetermined continuous pressure reducing operation is slow when said stability of said pulse wave is low.