Automatic blood-pressure measuring apparatus

• US 6,602,198 B2
• Filed: 09/28/2001
• Issued: 08/05/2003
• Est. Priority Date: 10/30/2000
• Status: Expired due to Fees

• Current Assignee: Omron Healthcare Company Limited (Omron Corporation)
• Original Assignee: Colin Corporation (Fukuda Denshi Company Limited)
• Inventors: Yokozeki, Akihiro
• Primary Examiner(s): Nasser, Robert L.
• Assistant Examiner(s): MALLARI, PATRICIA C
• Application Number:
  US09/964,574
• Publication Number:
  US 20020052554A1
• Time in Patent Office: 676 Days
• Field of Search: 600/485-504
• US Class Current: 600/485
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/02125 of pulse wave propagation time
• CPC Class Codes: A61B 5/6843 Monitoring or controlling sensor contact pressure

Abstract

An apparatus for automatically measuring a blood pressure of a living subject, including an inflatable cuff which is wound around a portion of the subject, a cuff pulse wave including heartbeat-synchronous pulses occurring to the cuff when a pressure in the cuff is changed, a pressure-pulse-wave detecting device which includes a pressure-pulse-wave sensor that is pressed against an artery of the subject and which detects, through the sensor, a pressure pulse wave that is produced by the artery when the pressure of the cuff is changed and that includes heartbeat-synchronous pulses, a correction-factor determining device for determining, for each of the heartbeat-synchronous pulses of the pressure pulse wave, a correction factor to correct an amplitude of each heartbeat-synchronous pulse to a predetermined value, a corrected-cuff-pulse-wave-amplitude determining device for multiplying, by the correction factor determined for each of the heartbeat-synchronous pulses of the pressure pulse wave, an amplitude of one of the heartbeat-synchronous pulses of the cuff pulse wave that corresponds to each heartbeat-synchronous pulse of the pressure pulse wave, and thereby determining a corrected amplitude of the one heartbeat-synchronous pulse of the cuff pulse wave, and a blood-pressure determining device for determining a blood pressure of the subject based on a change of the respective corrected amplitudes of the respective pulses of the cuff pulse wave, with respect to the pressure of the cuff.

Claims

1. An apparatus for automatically measuring 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 when a pressure in 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 detects, through the pressure-pulse-wave sensor, a pressure pulse wave that is produced by the artery when the pressure of the cuff is changed and that includes a plurality of heartbeat-synchronous pulses;

an average-pressure determining means for determining an average pressure of respective reference pressures of the heartbeat-synchronous pulses of the pressure pulse wave that are detected by the pressure-pulse-wave detecting device when the pressure of the cuff is changed;

a corrected-cuff-pressure determining means for subtracting, from a pressure of the cuff at a time of detection of one of the heartbeat-synchronous pulses of the cuff pulse wave that corresponds to each of the heartbeat-synchronous pulses of the pressure pulse wave, a pressure difference obtained by subtracting, from the reference pressure of said each heartbeat-synchronous pulse of the pressure pulse wave, the average pressure determined by the average-pressure determining means, and thereby determining a corrected pressure of the cuff; and

a blood-pressure determining means for determining a blood pressure of the subject based on a change of respective amplitudes of the respective heartbeat-synchronous pulses of the cuff pulse wave, with respect to the respective corrected pressures of the cuff.

2. An apparatus according to claim 1, wherein the average-pressure determining means comprises means for determining the average pressure of respective middle pressures of the heartbeat-synchronous pulses of the pressure pulse wave that are detected by the pressure-pulse-wave detecting device when the pressure of the cuff is changed, and wherein the corrected-cuff-pressure determining means comprises means for subtracting, from the pressure of the cuff at the time of detection of said one of the heartbeat-synchronous pulses of the cuff pulse wave that corresponds to said each of the heartbeat-synchronous pulses of the pressure pulse wave, the pressure difference obtained by subtracting, from the middle pressure of said each heartbeat-synchronous pulse of the pressure pulse wave, the average pressure determined by the average-pressure determining means, and thereby determining the corrected pressure of the cuff.

3. An apparatus for automatically measuring a blood pressure of a living subject, comprising:

an inflatable cuff which is adapted to be wound around a portion of the subject and which is connected to a pressure sensor for detecting a cuff pulse wave including a plurality of heartbeat-synchronous pulses occurring to the cuff when a pressure in 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 which is other than the downstream from the cuff and which detects, through the pressure-pulse-wave sensor, a pressure pulse wave that is produced by the artery when the pressure of the cuff is changed and that includes a plurality of heartbeat-synchronous pulses;

a correction-factor determining means for determining, for each of the heartbeat-synchronous pulses of the pressure pulse wave, a correction factor to correct an amplitude of said each heartbeat-synchronous pulse to a predetermined value;

a corrected-cuff-pulse-wave-amplitude determining means for multiplying, by the correction factor determined by the correction-factor determining means for said each of the heartbeat-synchronous pulses of the pressure pulse wave, an amplitude of one of the heartbeat-synchronous pulses of the cuff pulse wave that corresponds to said each heartbeat-synchronous pulse of the pressure pulse wave, and thereby determining a corrected amplitude of said one heartbeat-synchronous pulse of the cuff pulse wave; and

a blood-pressure determining means for determining a blood pressure of the subject according to the oscillometric method based on a change of the respective corrected amplitudes of the respective heartbeat-synchronous pulses of the cuff pulse wave, with respect to the pressure of the cuff.

4. An apparatus according to claim 3, 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.

5. An apparatus according to claim 3, wherein the correction-factor determining means comprises:

means for determining an average amplitude of respective amplitudes of the heartbeat-synchronous pulses of the pressure pulse wave; and

means for determining, for said each of the heartbeat-synchronous pulses of the pressure pulse wave, the correction factor to correct the amplitude of said each heartbeat-synchronous pulse to the determined average amplitude as the predetermined value.

6. An apparatus for automatically measuring 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 when a pressure in 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 detects, through the pressure-pulse-wave sensor, a pressure pulse wave that is produced by the artery when the pressure of the cuff is changed and that includes a plurality of heartbeat-synchronous pulses;

a correction-factor determining means for determining, for each of the heartbeat-synchronous pulses of the pressure pulse wave, a correction factor to correct an amplitude of said each heartbeat-synchronous pulse to a predetermined value;

a corrected-cuff-pulse-wave-amplitude determining means for multiplying, by the correction factor determined by the correction-factor determining means for said each of the heartbeat-synchronous pulses of the pressure pulse wave, an amplitude of one of the heartbeat-synchronous pulses of the cuff pulse wave that corresponds to said each heartbeat-synchronous pulse of the pressure pulse wave;

an average-pressure determining means for determining an average pressure of respective reference pressures of the heartbeat-synchronous pulses of the pressure pulse wave that are detected by the pressure-pulse-wave detecting device when the pressure of the cuff is changed;

a corrected-cuff-pressure determining means for subtracting, from a pressure of the cuff at a time of detection of said one of the heartbeat-synchronous pulses of the cuff pulse wave that corresponds to said each of the heartbeat-synchronous pulses of the pressure pulse wave, a pressure difference obtained by subtracting, from the reference pressure of said each heartbeat-synchronous pulse of the pressure pulse wave, the average pressure determined by the average-pressure determining means; and

a blood-pressure determining means for determining a blood pressure of the subject based on a change of the respective corrected amplitudes of the respective heartbeat-synchronous pulses of the cuff pulse wave, with respect to the respective corrected pressures of the cuff.

7. An apparatus for automatically measuring 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 when a pressure in 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 detects, through the pressure-pulse-wave sensor, a pressure pulse wave that is produced by the artery when the pressure of the cuff is changed and that includes a plurality of heartbeat synchronous pulses;

a correction-factor determining means for determining, for each of the heartbeat-synchronous pulses of the pressure pulse wave, a correction factor to correct an amplitude of said each heartbeat-synchronous pulse to a predetermined value;

a corrected-cuff-pulse-wave-amplitude determining means for multiplying, by the correction factor determined by the correction-factor determining means for said each of the heartbeat-synchronous pulses of the pressure pulse wave, an amplitude of one of the heartbeat-synchronous pulses of the cuff pulse wave that corresponds to said each heartbeat-synchronous pulse of the pressure pulse wave, and thereby determining a corrected amplitude of said one heartbeat-synchronous pulse of the cuff pulse wave; and

a blood-pressure determining means for determining a blood pressure of the subject based on a change of the respective corrected amplitudes of the respective heartbeat-synchronous pulses of the cuff pulse wave, with respect to the pressure of the cuff;

wherein the correction-factor determining means comprises;

means for determining an average amplitude of respective amplitudes of the heartbeat-synchronous pulses of the pressure pulse wave; and

means for determining, for said each of the heartbeat-synchronous pulses of the pressure pulse wave, the correction factor to correct the amplitude of said each heartbeat-synchronous pulse to the determined average amplitude as the predetermined value.