Continuous blood-pressure monitoring apparatus

• US 6,645,156 B2
• Filed: 11/02/2001
• Issued: 11/11/2003
• Est. Priority Date: 03/21/2001
• Status: Expired due to Fees

• Current Assignee: Omron Healthcare Company Limited (Omron Corporation)
• Original Assignee: Colin Corporation (Fukuda Denshi Company Limited)
• Inventors: Oka, Tohru
• Primary Examiner(s): Hindenburg, Max F.
• Assistant Examiner(s): Natnithithadha, Navin
• Application Number:
  US09/985,408
• Publication Number:
  US 20020138010A1
• Time in Patent Office: 739 Days
• Field of Search: 600/490, 600/493, 600/494, 600/495, 600/496, 600/500, 600/485, 600/481
• US Class Current: 600/490
• CPC Class Codes: A61B 5/0285 Measuring or recording phase velocity of blood waves

Abstract

A continuous blood-pressure monitoring device apparatus including a cuff, a first determining device, a detecting device which detects a pressure pulse wave produced by an artery, a second determining device, a monitoring device, an information obtaining device a first change-value determining device, a second change-value determining device, and a relationship checking device.

Claims

1. An apparatus for continuously monitoring a blood pressure of a living subject, comprising:

an inflatable cuff which is adapted to be wound around a portion of the subject, a cuff pulse wave including a plurality of heartbeat-synchronous pulses occurring to the cuff while a pressure in the cuff is changed;

a blood-pressure determining means for determining a blood pressure of the subject based on a signal obtained while the pressure of the cuff is changed;

a pressure-pulse-wave detecting device which includes a pressure-pulse-wave sensor that is adapted to be pressed against an artery of the subject and which continuously detects, through the pressure-pulse-wave sensor, a pressure pulse wave that is produced by the artery and includes a plurality of heartbeat-synchronous pulses;

a relationship determining means for determining a relationship between blood pressure and magnitude of pressure pulse wave, based on the blood pressure determined by the blood-pressure determining means and a magnitude of the pressure pulse wave detected by the pressure-pulse-wave detecting device;

a blood-pressure monitoring means for iteratively determining, according to the thus determined relationship, a monitor blood-pressure value of the subject based on a magnitude of each of the heartbeat-synchronous pulses of the pressure pulse wave detected by the pressure-pulse-wave detecting device;

a pulse-wave-propagation-velocity-related-information obtaining means for iteratively obtaining, in a state in which the pressure of the cuff is held at a prescribed pulse-wave-detection pressure lower than a diastolic blood pressure of the subject, a piece of pulse-wave-propagation-velocity-related information which is related to a velocity at which a pulse wave propagates through the artery of the subject, based on a time of occurrence of a prescribed periodic point of a heartbeat-synchronous pulse of the cuff pulse wave and a time of occurrence of a prescribed periodic point of a corresponding heartbeat-synchronous pulse of the pressure pulse wave;

a propagation-velocity-related-information-change-value determining means for periodically determining, at a prescribed judgment period, a change value of the pieces of pulse-wave-propagation-velocity-related information obtained by the pulse-wave-propagation-velocity-related-information obtaining means;

a monitor-blood-pressure-change-value determining means for periodically determining, at the judgment period, a change value of the monitor blood-pressure values determined by the blood-pressure monitoring means; and

a relationship checking means for comparing the change value of the pieces of pulse-wave-propagation-velocity-related information, determined by the propagation-velocity-related-information-change-value determining means, and the change value of the monitor blood-pressure values, determined by the monitor-blood-pressure-change-value determining means, with each other, and thereby judging whether the relationship between blood pressure and magnitude of pressure pulse wave, determined by the relationship determining means, is appropriate.

3. An apparatus according to claim 1, wherein the relationship checking means judges that the relationship between blood pressure and magnitude of pressure pulse wave is not appropriate, when a relative value between the change value of the pieces of pulse-wave-propagation-velocity-related information, determined by the propagation-velocity-related-information-change-value determining means, and the change value of the monitor blood-pressure values, determined by the monitor-blood-pressure-change-value determining means, does not fall within a normal range, and wherein the apparatus further comprises a normal-range determining means for determining, as the normal range, a narrower range when the monitor blood-pressure value used to determine the change value of the monitor blood-pressure values is lower than a prescribed danger value which indicates that the subject needs an urgent treatment, than a range determined thereby when the monitor blood-pressure value is not lower than the danger value.

5. An apparatus according to claim 1, wherein the relationship checking means comprises means for operating, when it is judged that the relationship between blood pressure and magnitude of pressure pulse wave is not appropriate, the relationship determining means to update said relationship.

7. An apparatus according to claim 1, further comprising:

a pressure changing device which changes the pressure of the cuff;

a pressure sensor which detects the pressure of the cuff changed by the pressure changing device; and

a cuff-pulse-wave detecting device which detects the cuff pulse wave occurring to the cuff.

2. An apparatus for continuously monitoring a blood pressure of a living subject, comprising:

an inflatable cuff which is adapted to be wound around a portion of the subject, a cuff pulse wave including a plurality of heartbeat-synchronous pulses occurring to the cuff while a pressure in the cuff is changed;

a blood-pressure determining means for determining a blood pressure of the subject based on a signal obtained while the pressure of the cuff is changed;

a pressure-pulse-wave detecting device which includes a pressure-pulse-wave sensor that is adapted to be pressed against an artery of the subject and which continuously detects, through the pressure-pulse-wave sensor, a pressure pulse wave that is produced by the artery and includes a plurality of heartbeat-synchronous pulses;

a first relationship determining means for determining a first relationship between blood pressure and magnitude of pressure pulse wave, based on the blood pressure determined by the blood-pressure determining means and a magnitude of the pressure pulse wave detected by the pressure-pulse-wave detecting device;

a blood-pressure monitoring means for successively determining, according to the thus determined first relationship, a monitor blood-pressure value of the subject based on a magnitude of each of the heartbeat-synchronous pulses of the pressure pulse wave detected by the pressure-pulse-wave detecting device;

a standard-pulse-wave-propagation-velocity-related-information obtaining means for obtaining, as a standard piece of pulse-wave-propagation-velocity-related information, a piece of pulse-wave-propagation-velocity-related information which is related to a velocity at which a pulse wave propagates through the artery of the subject, based on a time of occurrence of a prescribed periodic point of a heartbeat-synchronous pulse of the cuff pulse wave in a first time duration comprising at least one of a first time period in which the pressure of the cuff is changed, a prescribed preceding time period preceding the first time period, and a prescribed following time period following the first time period, and a time of occurrence of a prescribed periodic point of a corresponding heartbeat-synchronous pulse of the pressure pulse wave in the first time duration;

a second relationship determining means for determining a second relationship between blood pressure and pulse-wave-propagation-velocity-related information, based on the blood pressure determined by the blood-pressure determining means and the standard piece of pulse-wave-propagation-velocity-related information obtained by the standard-pulse-wave-propagation-velocity-related-information obtaining means;

a cuff-pressure changing means for periodically increasing, at a prescribed judgment period, the pressure of the cuff up to a prescribed pulse-wave-detection pressure lower than a diastolic blood pressure of the subject;

a judgment-pulse-wave-propagation-velocity-related-information obtaining means for obtaining, as a judgment piece of pulse-wave-propagation-velocity-related information, a piece of pulse-wave-propagation-velocity-related information which is related to the velocity at which the pulse wave propagates through the artery of the subject, based on a time of occurrence of a prescribed periodic point of a heartbeat-synchronous pulse of the cuff pulse wave occurring to the cuff in a state in which the pressure of the cuff is held at the pulse-wave-detection pressure by the cuff-pressure changing means, and a time of occurrence of a prescribed periodic point of a corresponding heartbeat-synchronous pulse of the pressure pulse wave detected by the pressure-pulse-wave detecting device in said state;

an estimated-blood-pressure determining means for determining, according to the second relationship, an estimated blood-pressure value of the subject based on the judgment piece of pulse-wave-propagation-velocity-related information obtained by the judgment-pulse-wave-propagation-velocity-related-information obtaining means; and

a relationship checking means for comparing the estimated blood-pressure value determined by the estimated-blood-pressure determining means, and a monitor blood-pressure value determined by the blood-pressure monitoring means based on a magnitude of a heartbeat-synchronous pulse of the pressure pulse wave detected by the pressure-pulse-wave detecting device in a second time duration comprising at least one of a second time period in which the pressure of the cuff is held at the pulse-wave-detection pressure by the cuff-pressure changing means, a prescribed preceding time period preceding the second time period, and a prescribed following time period following the second time period, with each other, and thereby judging whether the relationship between blood pressure and magnitude of pressure pulse wave, determined by the first relationship determining means, is appropriate.

4. An apparatus according to claim 2, wherein the relationship checking means judges that the relationship between blood pressure and magnitude of pressure pulse wave is not appropriate, when a relative value between the estimated blood-pressure value determined by the estimated-blood-pressure determining means, and a monitor blood-pressure value determined by the blood-pressure monitoring means based on a magnitude of a heartbeat-synchronous pulse of the pressure pulse wave detected by the pressure-pulse-wave detecting device in the second time period in which the pressure of the cuff is held at the pulse-wave-detection pressure by the cuff-pressure changing means, does not fall within a normal range, and wherein the apparatus further comprises a normal-range determining means for determining, as the normal range, a narrower range when at least one of the estimated blood-pressure value and the monitor blood-pressure value is lower than a prescribed danger value which indicates that the subject needs an urgent treatment, than a range determined thereby when each of the estimated blood-pressure value and the monitor blood-pressure value is not lower than the danger value.

6. An apparatus according to claim 2, wherein the relationship checking means comprises means for operating, when it is judged that the first relationship between blood pressure and magnitude of pressure pulse wave is not appropriate, the first relationship determining means to update the first relationship.