Blood-pressure monitoring apparatus

• US 6,241,680 B1
• Filed: 09/20/1999
• Issued: 06/05/2001
• Est. Priority Date: 10/30/1998
• Status: Expired due to Fees

• Current Assignee: Omron Healthcare Company Limited (Omron Corporation)
• Original Assignee: Colin Corporation (Fukuda Denshi Company Limited)
• Inventors: Miwa, Yoshihisa
• Primary Examiner(s): Winakur, Eric F.
• Assistant Examiner(s): Natnithithadha, Navin
• Application Number:
  US09/399,735
• Time in Patent Office: 624 Days
• Field of Search: 600/494, 600/493, 600/495, 600/496, 600/490, 600/500, 600/501, 600/502
• US Class Current: 600/494
• CPC Class Codes: A61B 5/02208 using the Korotkoff method
• CPC Class Codes: A61B 5/02225 using the oscillometric method
• CPC Class Codes: A61B 5/02255 the pressure being controlled by plethysmographic signals, e.g. derived from optical sensors
• CPC Class Codes: A61B 5/0285 Measuring or recording phase velocity of blood waves

Abstract

A blood-pressure monitoring apparatus including an inflatable cuff adapted to apply a pressing pressure to a body portion of a living subject, a cuff-pulse-wave detecting device which detects a cuff pulse wave which is produced in the inflatable cuff when the cuff applies the pressing pressure to the body portion of the subject, a pressure control device which increases the pressing pressure of the inflatable cuff to a predetermined value lower than a mean blood-pressure value of the subject, an index-value calculating device for iteratively calculating an index value indicative of a condition of a circulatory system of the living subject, a starting device for judging whether each of the index values calculated by the index-value calculating device is abnormal and, when the each index value is judged as being abnormal, starting the pressure control device to increase the pressing pressure of the cuff to the predetermined value, and an abnormality judging device for judging whether the subject has an abnormal blood-pressure value, based on at least one of respective amplitudes of heartbeat-synchronous pulses of the pulse wave detected by the pulse-wave detecting device when the pressing pressure of the cuff is increased to the predetermined value by the pressure control device.

Claims

1. A blood-pressure monitoring apparatus comprising:

an inflatable cuff adapted to apply a pressing pressure to a body portion of a living subject;

a cuff-pulse-wave detecting device which detects a cuff pulse wave which is produced in the inflatable cuff when the inflatable cuff applies the pressing pressure to the body portion of the living subject, the cuff pulse wave comprising a plurality of heartbeat-synchronous pulses;

a pressure control device which increases the pressing pressure of the inflatable cuff to a predetermined value lower than a mean blood-pressure value of the living subject;

index-value calculating means for iteratively calculating an index value indicative of a condition of a circulatory system of the living subject;

starting means for judging whether each of the index values calculated by the index-value calculating means is abnormal and, when said each index value is judged as being abnormal, starting the pressure control device to increase the pressing pressure of the inflatable cuff to the predetermined value;

change-rate calculating means for calculating a rate of change of respective amplitudes of the heartbeat-synchronous pulses of the pulse wave detected by the pulse-wave detecting device when the pressing pressure of the inflatable cuff is increased to the predetermined value by the pressure control device, with respect to the pressing pressure of the inflatable cuff increased by the pressure control device; and

abnormality judging means for judging, based on the calculated rate of change, whether the living subject has an abnormal blood-pressure value.

2. An apparatus according to claim 1, further comprising a measuring device which measures a blood-pressure value of the living subject by changing the pressing pressure of the inflatable cuff, wherein the abnormality judging means comprises starting means for starting, when the living subject is judged as having the abnormal blood-pressure value, a blood-pressure measurement of the measuring device.

3. An apparatus according to claim 1, further comprising a periodically measuring device which periodically measures, at a predetermined period, a blood-pressure value of the living subject by changing the pressing pressure of the inflatable cuff.

4. An apparatus according to claim 1, wherein the index-value calculating means comprises:

a volumetric-pulse-wave sensor which detects a volumetric pulse wave from a peripheral body portion of the living subject, the volumetric pulse wave comprising a plurality of heartbeat-synchronous pulses; and

pulse-wave-area-relating-value calculating means for iteratively calculating, as said each index value, a value relating to an area of each of the heartbeat-synchronous pulses of the volumetric pulse wave.

5. An apparatus according to claim 1, wherein the starting means comprises:

change-value calculating means for iteratively calculating a change value relating to a change of said each index value from a value based on at least one prior index value;

judging means for judging, when the calculated change value does not fall within a reference range, that said each index value is abnormal; and

control means for starting the pressure control device to increase the pressing pressure of the inflatable cuff to the predetermined value.

6. An apparatus according to claim 1, wherein the change-rate calculating means comprises a memory which stores the respective amplitudes of the heartbeat-synchronous pulses of the pulse wave detected by the pulse-wave detecting device when the pressing pressure of the inflatable cuff is increased to the predetermined value by the pressure control device.

7. An apparatus according to claim 1, wherein the abnormality judging means comprises judging means for judging, when the calculated rate of change is greater than a predetermined value, that the living subject has the abnormal blood-pressure value.

8. An apparatus according to claim 1, wherein the abnormality judging means comprises judging means for judging that the living subject has the abnormal blood-pressure value, when a greatest one of the respective amplitudes of the heartbeat-synchronous pulses of the pulse wave detected by the pulse-wave detecting device when the pressing pressure of the inflatable cuff is increased to the predetermined value by the pressure control device is smaller than a predetermined value.

9. An apparatus according to claim 1, further comprising an informing device which informs, when the abnormality judging means judges that the living subject has the abnormal blood-pressure value, a person of an occurrence of abnormality to the blood pressure of the living subject.

10. An apparatus according to claim 1, wherein the starting means comprises judging means for judging that said each index value is abnormal, when a value based on said each index value satisfies a predetermined condition with respect to at least one predetermined value.

11. An apparatus according to claim 1, wherein the abnormality judging means comprises judging means for judging that the living subject has the abnormal blood-pressure value, when the calculated rate of change satisfies a predetermined condition with respect to at least one predetermined value.

12. A blood-pressure monitoring apparatus comprising:

an inflatable cuff adapted to apply a pressing pressure to a body portion of a living subject;

a cuff-pulse-wave detecting device which detects a cuff pulse wave which is produced in the inflatable cuff when the cuff applies the pressing pressure to the body portion of the living subject, the cuff pulse wave comprising a plurality of heartbeat-synchronous pulses;

a pressure control device which increases the pressing pressure of the inflatable cuff to a predetermined value lower than a mean blood-pressure value of the living subject;

index-value calculating means for iteratively calculating an index value indicative of a condition of a circulatory system of the living subject;

starting means for judging whether each of the index values calculated by the index-value calculating means is abnormal and, when said each index value is judged as being abnormal, starting the pressure control device to increase the pressing pressure of the inflatable cuff to the predetermined value; and

abnormality judging means for judging whether the living subject has an abnormal blood-pressure value, based on at least one of respective amplitudes of the heartbeat-synchronous pulses of the pulse wave detected by the pulse-wave detecting device when the pressing pressure of the inflatable cuff is increased to the predetermined value by the pressure control device.

13. An apparatus according to claim 12, further comprising change-rate calculating means for calculating a rate of change of the respective amplitudes of the heartbeat-synchronous pulses of the pulse wave detected by the pulse-wave detecting device when the pressing pressure of the inflatable cuff is increased to the predetermined value by the pressure control device, with respect to the pressing pressure of the inflatable cuff increased by the pressure control device, wherein the abnormality judging means comprises judging means for judging, based on the calculated rate of change, whether the living subject has the abnormal blood-pressure value.

14. An apparatus according to claim 12, wherein the abnormality judging means comprises judging means for judging whether the living subject has the abnormal blood-pressure value, based on a greatest one of the respective amplitudes of the heartbeat-synchronous pulses of the pulse wave detected by the pulse-wave detecting device when the pressing pressure of the inflatable cuff is increased to the predetermined value by the pressure control device.