Pulse-wave-propagation-velocity-related-information obtaining apparatus

• US 6,699,197 B2
• Filed: 02/12/2002
• Issued: 03/02/2004
• Est. Priority Date: 07/02/2001
• Status: Expired due to Fees

• Current Assignee: Omron Healthcare Company Limited (Omron Corporation)
• Original Assignee: Colin Corporation (Fukuda Denshi Company Limited)
• Inventors: Narimatsu, Kiyoyuki
• Primary Examiner(s): Nasser, Robert L.
• Assistant Examiner(s): MALLARI, PATRICIA C
• Application Number:
  US10/073,025
• Publication Number:
  US 20030004420A1
• Time in Patent Office: 749 Days
• Field of Search: 600/485, 600/481, 600/490-495, 600/500-504, 600/506, 600/507
• US Class Current: 600/500
• CPC Class Codes: A61B 5/02 Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• 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 5/0285 Measuring or recording phase velocity of blood waves
• CPC Class Codes: A61B 5/6822 Neck
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives

Abstract

An apparatus for obtaining information related to a velocity at which a pulse wave propagates in a living subject, the apparatus including a pulse-wave sensor which is adapted to be worn on a body portion of the subject and detects the pulse wave from the body portion, an incident-wave-peak determining device for determining a peak of an incident-wave component which is contained in the pulse wave detected by the pulse-wave sensor, a reflected-wave-peak determining device for determining a peak of a reflected-wave component which is contained in the pulse wave detected by the pulse-wave sensor, and an information obtaining device for obtaining the information based on a time difference between the peak of the incident-wave component determined by the incident-wave-peak determining device and the peak of the reflected-wave component determined by the reflected-wave-peak determining device.

Claims

1. An apparatus for obtaining information related to a velocity at which a pulse wave propagates in a living subject, the apparatus comprising:

a pulse-wave sensor which is adapted to be worn on a body portion of the subject and detects the pulse wave from the body portion;

an incident-wave-peak determining means for determining a peak of an incident-wave component which is contained in the pulse wave detected by the pulse-wave sensor;

a reflected-wave-peak determining means for determining a peak of a reflected-wave component which is contained in the pulse wave detected by the pulse-wave sensor;

an information obtaining means for obtaining the information based on a time difference between the peak of the incident-wave component determined by the incident-wave-peak determining means and the peak of the reflected-wave component determined by the reflected-wave-peak determining means; and

an arteriosclerosis-degree determining means for determining a degree of arteriosclerosis of the subject, based on the information obtained by the information obtaining means, according to a prescribed relationship between information related to velocity of propagation of pulse wave and degree of arteriosclerosis.

2. An apparatus according to claim 1, wherein the reflected-wave-peak determining means comprises:

means for differentiating the pulse wave detected by the pulse-wave sensor; and

means for determining, as the peak of the reflected-wave component, a maximal point of the pulse wave.

3. An apparatus according to claim 1, further comprising a display device which displays the information obtained by the information obtaining means.

4. An apparatus according to claim 1, further comprising a display device which displays the degree of arteriosclerosis determined by the arteriosclerosis-degree determining means.

5. An apparatus according to claim 1, wherein the pulse-wave sensor comprises a pressure-pulse-wave sensor which is adapted to be pressed against an artery of the subject and detects, as the pulse wave, a pressure pulse wave produced from the artery.

6. An apparatus according to claim 5, wherein the pressure-pulse-wave sensor detects the pressure pulse wave produced from the artery selected from the group consisting of a carotid artery, a brachial artery, a radial artery, and a femoral artery.

7. An apparatus according to claim 5, wherein the pressure-pulse-wave sensor comprises a plurality of pressure-sensing elements each of which can detect the pressure pulse wave produced from the artery, and a pressing surface in which the pressure-sensing elements are arranged in at least one array such that in a state in which the pressure-pulse-wave sensor is worn on the body portion and the press surface is pressed against a surface of the body portion, the array of the pressure-sensing elements crosses over the artery and at least one of the pressure-sensing elements is positioned right above the artery.

8. An apparatus according to claim 1, wherein the incident-wave-peak determining means determines the peak of the incident-wave component, by differentiating the pulse wave detected by the pulse-wave sensor.

9. An apparatus according to claim 8, wherein the incident-wave-peak determining means comprises:

means for determining a rising point and a maximal point of a heartbeat-synchronous pulse of the pulse wave detected by the pulse-wave sensor;

means for differentiating a portion of the pulse wave between the rising point and the maximal point; and

means for determining, as the peak of the incident-wave component, an inflection point of the differentiated portion of the pulse wave.