Blood-pressure monitoring apparatus

• US 6,251,081 B1
• Filed: 09/08/1999
• Issued: 06/26/2001
• Est. Priority Date: 10/01/1998
• Status: Expired due to Fees

• Current Assignee: Colin Medical Technology Corporation (Omron Corporation)
• Original Assignee: Colin Corporation (Fukuda Denshi Company Limited)
• Inventors: Narimatsu, Kiyoyuki
• Primary Examiner(s): Sykes, Angela D.
• Assistant Examiner(s): CARTER, RYAN CHRISTOPHER
• Application Number:
  US09/392,236
• Time in Patent Office: 657 Days
• Field of Search: 600/300-301, 600/500-508, 600/481-491, 128/897-899, 128/920-925
• US Class Current: 600/490
• CPC Class Codes: A61B 5/02125 of pulse wave propagation time
• CPC Class Codes: A61B 5/022 by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers

Abstract

A blood-pressure monitoring apparatus including a measuring device which periodically measures a blood-pressure value of a living subject at a predetermined period, and a predicting device or circuit which predicts, based on the blood-pressure values measured by the measuring device, a blood-pressure value of the living subject at a time later by a predetermined time than a time when the last one of the blood-pressure values is measured by the measuring device.

Claims

1. A blood-pressure monitoring apparatus comprising:

a measuring device which periodically measures a blood-pressure value of a living subject at a predetermined period; and

predicting means for predicting, based on a plurality of blood-pressure values measured by the measuring device, a blood-pressure value of the living subject at a time later as defined by a predetermined time interval than when a last one of the plurality of blood-pressure values is measured by the measuring device.

2. An apparatus according to claim 1, wherein the predicting means comprises central-value determining means for determining, as the predicted blood-pressure value, a central value of a blood-pressure range within which the blood pressure of the living subject is predicted, based on the plurality of blood-pressure values, to fall at the later time.

3. An apparatus according to claim 1, wherein the measuring device comprises an inflatable cuff, the measuring device periodically measuring a blood-pressure value of the living subject while changing a pressing pressure of the cuff applied to a body portion of the subject.

4. An apparatus according to claim 1, further comprising period changing means for changing, when the predicted blood-pressure value does not fall within a reference blood-pressure range, the predetermined period to a changed period shorter than the predetermined period, so that the measuring device measures a blood-pressure value of the living subject at the changed period.

5. An apparatus according to claim 1, further comprising period changing means for changing, when the predicted blood-pressure value is greater than a reference blood-pressure value, the predetermined period to a changed period shorter than the predetermined period, so that the measuring device measures a blood-pressure value of the living subject at the changed period.

6. An apparatus according to claim 1, further comprising period changing means for changing, when the predicted blood-pressure value is smaller than a reference blood-pressure value, the predetermined period to a changed period shorter than the predetermined period, so that the measuring device measures a blood-pressure value of the living subject at the changed period.

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

measured-blood-pressure-value displaying means for displaying a graph representing a time-wise trend of the plurality of blood-pressure values measured by the measuring device, on a two-dimensional coordinate system defined by a first axis indicative of a plurality of times at which the plurality of blood-pressure values are measured by the measuring device, respectively, and a second axis indicative of the plurality of blood-pressure values measured by the measuring device; and

predicted-blood-pressure-value displaying means for displaying, on the coordinate system, a graph representing the blood-pressure value predicted by the predicting means.

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

probability calculating means for calculating a probability with which a blood-pressure value of the living subject measured by the measuring device at the later time is equal to the predicted blood-pressure value, according to a predetermined relationship between time and probability;

probability-distribution calculating means for calculating, based on the calculated probability, a normal distribution of probability of the blood-pressure value of the living subject measured by the measuring device at the later time; and

range determining means for determining a blood-pressure range whose central value is equal to the predicted blood-pressure value and within which the blood-pressure value of the living subject measured by the measuring device at the later time falls with a predetermined probability.

9. An apparatus according to claim 8, further comprising period changing means for changing, when at least one of an upper limit value and a lower limit value of the determined blood-pressure range does not fall within a reference blood-pressure range, the predetermined period to a changed period shorter than the predetermined period, so that the measuring device measures a blood-pressure value of the living subject at the changed period.

10. An apparatus according to claim 8, further comprising period changing means for changing, when at least one of an upper limit value and a lower limit value of the determined blood-pressure range is greater than a reference blood-pressure value, the predetermined period to a changed period shorter than the predetermined period, so that the measuring device measures a blood-pressure value of the living subject at the changed period.

11. An apparatus according to claim 8, further comprising period changing means for changing, when at least one of an upper limit value and a lower limit value of the determined blood-pressure range is smaller than a reference blood-pressure value, the predetermined period to a changed period shorter than the predetermined period, so that the measuring device measures a blood-pressure value of the living subject at the changed period.

12. An apparatus according to claim 8, further comprising:

measured-blood-pressure-value displaying means for displaying a graph representing a time-wise trend of the plurality of blood-pressure values measured by the measuring device, on a two-dimensional coordinate system defined by a first axis indicative of a plurality of times at which the plurality of blood-pressure values are measured by the measuring device, respectively, and a second axis indicative of the plurality of blood-pressure values measured by the measuring device;

predicted-blood-pressure-value displaying means for displaying, on the coordinate system, a graph representing the blood-pressure value predicted by the predicting means; and

range displaying means for displaying, on the coordinate system, a graph representing the blood-pressure range determined by the range determining means.

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

pulse-wave-propagation-information obtaining means for iteratively obtaining, from the living subject, a set of information relating to propagation of a pulse wave through an arterial vessel of the subject;

estimating means for iteratively estimating a blood-pressure value of the living subject, based on each set of information of the iteratively obtained sets of information, according to a predetermined relationship between pulse-wave-propagation information and blood pressure; and

predicted-blood-pressure-value modifying means for modifying, based on the estimated blood-pressure value, the blood-pressure value predicted by the predicting means.

14. An apparatus according to claim 13, further comprising:

period changing means for changing, when the predicted blood-pressure value does not fall within a reference blood-pressure range, the predetermined period to a changed period shorter than the predetermined period, so that the measuring device measures a blood-pressure value of the living subject at the changed period; and

period re-changing means for re-changing, when the modified blood-pressure value falls within the reference blood-pressure range after the predetermined period is changed to the changed period, the changed period back to the predetermined period, so that the measuring device measures a blood-pressure value of the living subject at the predetermined period.

15. An apparatus according to claim 13, further comprising:

period changing means for changing, when the predicted blood-pressure value is greater than a reference blood-pressure value, the predetermined period to a changed period shorter than the predetermined period, so that the measuring device measures a blood-pressure value of the living subject at the changed period; and

period re-changing means for re-changing, when the modified blood-pressure value is not greater the reference blood-pressure value after the predetermined period is changed to the changed period, the changed period back to the predetermined period, so that the measuring device measures a blood-pressure value of the living subject at the predetermined period.

16. An apparatus according to claim 13, further comprising:

period changing means for changing, when the predicted blood-pressure value is smaller than a reference blood-pressure value, the predetermined period to a changed period shorter than the predetermined period, so that the measuring device measures a blood-pressure value of the living subject at the changed period; and

period re-changing means for re-changing, when the modified blood-pressure value is not smaller than the reference blood-pressure value after the predetermined period is changed to the changed period, the changed period back to the predetermined period, so that the measuring device measures a blood-pressure value of the living subject at the predetermined period.

17. An apparatus according to claim 13, further comprising:

probability calculating means for calculating a probability with which a blood-pressure value of the living subject measured by the measuring device at the later time is equal to the predicted blood-pressure value, according to a predetermined relationship between time and probability;

probability-distribution calculating means for calculating, based on the calculated probability, a normal distribution of probability of the blood-pressure value of the living subject measured by the measuring device at the later time; and

range determining means for determining a blood-pressure range whose central value is equal to the predicted blood-pressure value and within which the blood-pressure value of the living subject measured by the measuring device at the later time falls with a predetermined probability.

18. An apparatus according to claim 17, wherein the probability calculating means comprises means for calculating a probability with which a blood-pressure value of the living subject measured by the measuring device at the later time is equal to the modified blood-pressure value, according to the predetermined relationship between time and probability, the probability-distribution calculating means comprises means for calculating, based on the calculated probability, a normal distribution of probability of the blood-pressure value of the living subject measured by the measuring device at the later time, and the range determining means comprises means for determining a modified blood-pressure range whose central value is equal to the modified blood-pressure value and within which the blood-pressure value of the living subject measured by the measuring device at the later time falls with the predetermined probability, and wherein the apparatus further comprises period changing means for changing, when at least one of an upper limit value and a lower limit value of the determined blood-pressure range does not fall within a reference blood-pressure range, the predetermined period to a changed period shorter than the predetermined period, so that the measuring device measures a blood-pressure value of the living subject at the changed period;

and period re-changing means for re-changing, when at least one of an upper limit value and a lower limit value of the modified blood-pressure range falls within the reference blood-pressure range after the predetermined period is changed to the changed period, the changed period back to the predetermined period, so that the measuring device measures a blood-pressure value of the living subject at the predetermined period.

19. An apparatus according to claim 17, wherein the probability calculating means comprises means for calculating a probability with which a blood-pressure value of the living subject measured by the measuring device at the later time is equal to the modified blood-pressure value, according to the predetermined relationship between time and probability, the probability-distribution calculating means comprises means for calculating, based on the calculated probability, a normal distribution of probability of the blood-pressure value of the living subject measured by the measuring device at the later time, and the range determining means comprises means for determining a modified blood-pressure range whose central value is equal to the modified blood-pressure value and within which the blood-pressure value of the living subject measured by the measuring device at the later time falls with the predetermined probability, and wherein the apparatus further comprises period changing means for changing, when at least one of an upper limit value and a lower limit value of the determined blood-pressure range is greater than a reference blood-pressure value, the predetermined period to a changed period shorter than the predetermined period, so that the measuring device measures a blood-pressure value of the living subject at the changed period;

and period re-changing means for re-changing, when at least one of an upper limit value and a lower limit value of the modified blood-pressure range is not greater than the reference blood-pressure value after the predetermined period is changed to the changed period, the changed period back to the predetermined period, so that the measuring device measures a blood-pressure value of the living subject at the predetermined period.

20. An apparatus according to claim 17, wherein the probability calculating means comprises means for calculating a probability with which a blood-pressure value of the living subject measured by the measuring device at the later time is equal to the modified blood-pressure value, according to the predetermined relationship between time and probability, the probability-distribution calculating means comprises means for calculating, based on the calculated probability, a normal distribution of probability of the blood-pressure value of the living subject measured by the measuring device at the later time, and the range determining means comprises means for determining a modified blood-pressure range whose central value is equal to the modified blood-pressure value and within which the blood-pressure value of the living subject measured by the measuring device at the later time falls with the predetermined probability, and wherein the apparatus further comprises period changing means for changing, when at least one of an upper limit value and a lower limit value of the determined blood-pressure range is smaller than a reference blood-pressure value, the predetermined period to a changed period shorter than the predetermined period, so that the measuring device measures a blood-pressure value of the living subject at the changed period;

and period re-changing means for re-changing, when at least one of an upper limit value and a lower limit value of the modified blood-pressure range is not smaller than the reference blood-pressure value after the predetermined period is changed to the changed period, the changed period back to the predetermined period, so that the measuring device measures a blood-pressure value of the living subject at the predetermined period.