Blood pressure manometer and a method of calculating indices of atherosclerosis using the blood pressure manometer

• US 9,119,535 B2
• Filed: 12/08/2011
• Issued: 09/01/2015
• Est. Priority Date: 12/08/2010
• Status: Active Grant

• Current Assignee: Omron Healthcare Company Limited (Omron Corporation)
• Original Assignee: Omron Healthcare Company Limited (Omron Corporation)
• Inventors: Fujii, Kenji, Kobayashi, Tatsuya, Ogura, Toshihiko
• Primary Examiner(s): Mallari, Patricia
• Assistant Examiner(s): Ramachandran, Vasuda
• Application Number:
  US13/314,355
• Publication Number:
  US 20120172734A1
• Time in Patent Office: 1,363 Days
• Field of Search: 600/493
• US Class Current: 1/1
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 5/02125 of pulse wave propagation time
• CPC Class Codes: A61B 5/0225 the pressure being controlled by electric signals, e.g. derived from Korotkoff sounds

Abstract

A blood pressure measurement device accurately calculates an index useful in determining the degree of arteriosclerosis by accurately detecting a difference in time of appearance of a ejection wave and reflected wave in a blood pressure waveform. The device sets a threshold value based on an index that expresses a characteristic of the blood pressure waveform with respect to the point of appearance of the reflected wave in the blood pressure and estimates a rise point of the reflected wave by calculating an x-coordinate value of a point based on a maximum amplitude of the reflected wave and the threshold value. The device obtains the index of degree of arteriosclerosis by calculating a time difference in appearance between the ejection wave and the reflected wave based on the estimated rise point of the reflected wave.

Claims

1. A device for measuring blood pressure and calculating an index of degree of arteriosclerosis of a patient, the device comprising:

a cuff for wrapping around a measurement location of a patient, the cuff containing an air bladder;

an air pressure adjustor that adjusts an internal pressure of the air bladder;

a pressure sensor that detects changes of the internal pressure of the air bladder; and

a computation device that obtains a blood pressure waveform based on the changes of internal pressure of the air bladder detected by the pressure sensor, separates and identifies an ejection wave component and a reflected wave component from the blood pressure waveform, and calculates an index of degree of arteriosclerosis of the patient, the computation device further comprising;

a threshold value setting portion that variably sets a threshold value based on an index that expresses a characteristic of the blood pressure waveform with respect to a point of appearance of the reflected wave in the blood pressure waveform; and

a rise point estimating portion that estimates a rise point of the reflected wave by calculating an x-coordinate value of a point based on a maximum amplitude of the reflected wave and the threshold value,

wherein the index of degree of arteriosclerosis is obtained by calculating a time difference in appearance between the ejection wave and the reflected wave based on the estimated rise point of the reflected wave.

2. The device according to claim 1, wherein the index expressing the characteristic of the blood pressure waveform is an AI (augmentation index) value of the blood pressure waveform.

3. The device according to claim 1, wherein the measurement location is an upper arm of the patient.

4. A device for measuring blood pressure and calculating an index of degree of arteriosclerosis of a patient, the device comprising:

means containing an air bladder for wrapping around a measurement location of a patient;

means for adjusting an internal pressure of the air bladder;

means for detecting changes of the internal pressure of the air bladder; and

means for obtaining a blood pressure waveform based on the changes of internal pressure of the air bladder detected by the pressure sensor, separating and identifying an ejection wave component and a reflected wave component from the blood pressure waveform, and calculating an index of degree of arteriosclerosis of the patient, the means further comprising;

means for variably setting a threshold value based on an index that expresses a characteristic of the blood pressure waveform with respect to a point of appearance of the reflected wave in the blood pressure waveform; and

means for estimating a rise point of the reflected wave by calculating an x-coordinate value of a point based on a maximum amplitude of the reflected wave and the threshold value,

wherein the index of degree of arteriosclerosis is obtained by calculating a time difference in appearance between the ejection wave and the reflected wave based on the estimated rise point of the reflected wave.

5. The device according to claim 4, wherein the index expressing the characteristic of the blood pressure waveform is an AI (augmentation index) value of the blood pressure waveform.

6. The device according to claim 4, wherein the measurement location is an upper arm of the patient.