Blood pressure monitoring apparatus

• US 5,876,348 A
• Filed: 12/18/1997
• Issued: 03/02/1999
• Est. Priority Date: 01/06/1997
• Status: Expired due to Fees

• Current Assignee: Nihon Kohden Corporation
• Original Assignee: Nihon Kohden Corporation
• Inventors: Tanaka, Rie, Sugo, Yoshihiro, Sohma, Takeshi, Kasuya, Hiromitsu
• Primary Examiner(s): Nasser, Robert L.
• Assistant Examiner(s): ASTORINO, MICHAEL C
• Application Number:
  US08/993,562
• Time in Patent Office: 439 Days
• Field of Search: 600/500, 600/494, 600/495, 600/490, 600/485, 600/493
• 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
• CPC Class Codes: A61B 5/0285 Measuring or recording phase velocity of blood waves
• CPC Class Codes: A61B 5/352 Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval

Abstract

During a noninvasive blood pressure measurement using a cuff 2, a pulse wave propagation time T1 from the appearance of the peak value of an R wave in an electrocardiogram (ECG) waveform to the appearance of the bottom value of a pulse wave is counted, and a blood pressure value BP1 is calculated from a count result T1 and parameters α, β specific to a subject obtained during a pulse wave propagation time calibration. Then, the absolute value of a difference between the blood pressure value BP1 and a blood pressure value NIBP1 obtained by the noninvasive blood pressure measurement using the cuff 2 is calculated, and it is indeed whether or not the calculated absolute value is within a predetermined threshold_-- BP. If the absolute value is judged to exceed the threshold_-- BP, then blood pressure is measured again noninvasively using the cuff 2, and a blood pressure value NIBP1'"'"'obtained from such repeated measurement is displayed on a display 22.

Claims

1. A blood pressure monitoring apparatus comprising:

blood pressure measuring means for measuring blood pressure using a cuff;

time interval detection reference point detecting means for detecting a time interval detection reference point on a pulse wave at an aorta of a body;

pulse wave detecting means for detecting a pulse wave at peripheral blood vessels appearing with a time delay with respect to the pulse wave at the aorta;

pulse wave propagation time counting means for counting a pulse wave propagation time based on detected outputs from the time interval detection reference point detecting means and the pulse wave detecting means; and

control means for judging whether or not a blood pressure value measured by the blood pressure measuring means is an abnormal value based on a fluctuating condition observed on the blood pressure value measured by the blood pressure measuring means and a fluctuating condition observed on a pulse wave propagation time counted by the pulse wave propagation time counting means at the time the blood pressure value has been measured, and measuring blood pressure again by controlling the blood pressure measuring means when the blood pressure value has been judged to be an abnormal value.

2. A blood pressure monitoring apparatus comprising:

blood pressure measuring means for measuring blood pressure using a cuff;

threshold storage means for storing a threshold serving as a reference for blood pressure re-measurement using the cuff, the threshold being inputted from an external source;

time interval detection reference point detecting means for detecting a time interval detection reference point on a pulse wave at an aorta of a body;

pulse wave detecting means for detecting a pulse wave at peripheral blood vessels appearing with a time delay with respect to the pulse wave at the aorta;

pulse wave propagation time counting means for counting a pulse wave propagation time based on detected outputs from the time interval detection reference point detecting means and the pulse wave detecting means;

calculating means for calculating a blood pressure value based on a pulse wave propagation time counted by the pulse wave propagation time counting means at the time the blood pressure measurement has been made by the blood pressure measuring means; and

control means for judging whether or not an absolute value of a difference between a blood pressure value measured by the blood pressure measuring means and a blood pressure value calculated by the calculating means at the time the blood pressure value has been measured exceeds the threshold stored in the threshold storage means, and measuring blood pressure again by controlling the blood pressure measuring means when the absolute value of the difference has been judged to exceed the threshold.

3. A method for monitoring blood pressure comprising:

measuring blood pressure using a cuff;

detecting a time interval detection reference point on a pulse wave at an aorta of a body;

detecting a pulse wave at peripheral blood vessels appearing with a time delay with respect to the pulse wave at the aorta;

counting a pulse wave propagation time based on detected outputs from the time interval detection reference point and the pulse wave;

judging whether or not a blood pressure value is an abnormal value based on a fluctuating condition observed on the blood pressure value and a fluctuating condition observed on a pulse wave propagation time counted at the time the blood pressure value has been measured; and

measuring blood pressure again by controlling the blood pressure measuring means when the blood pressure value has been judged to be an abnormal value.

4. A method for monitoring blood pressure comprising:

measuring blood pressure using a cuff;

storing a threshold serving as a reference for blood pressure re-measurement using the cuff, the threshold being inputted from an external source;

detecting a time interval detection reference point on a pulse wave at an aorta of a body;

detecting a pulse wave at peripheral blood vessels appearing with a time delay with respect to the pulse wave at the aorta;

counting a pulse wave propagation time based on detected outputs from the time interval detection reference point and the pulse wave;

calculating a blood pressure value based on a pulse wave propagation time at the time the blood pressure measurement has been made; and

judging whether or not an absolute value of a difference between a blood pressure value and a blood pressure value calculated at the time the blood pressure value has been measured exceeds the threshold stored in the threshold storage means; and

measuring blood pressure again when the absolute value of the difference has been judged to exceed the threshold.