MEASUREMENT APPARATUS

• US 20130109982A1
• Filed: 12/18/2012
• Published: 05/02/2013
• Est. Priority Date: 07/20/2010
• Status: Active Grant

• Current Assignee: Omron Healthcare Company Limited (Omron Corporation)
• Original Assignee: Omron Healthcare Company Limited (Omron Corporation), Public University Corporation Nara Medical University
• Inventors: MORI, Naoki, OGURA, Toshihiko, ITO, Hirofumi, TAKAMATSU, Shozo, KICHIKAWA, Kimihiko, HASHIMOTO, Tomoko, UTSUNO, Hideo, SATO, Hironori
• Granted Patent: US 9,668,658 B2
• Time in Patent Office: Days
• US Class Current: 600/502
• CPC Class Codes: A61B 5/02014 Determining aneurysm
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/02444 Details of sensor A61B5/02427 takes precedence
• CPC Class Codes: A61B 5/0285 Measuring or recording phase velocity of blood waves
• CPC Class Codes: A61B 5/0295 using plethysmography, i.e. measuring the variations in the volume of a body part as modified by the circulation of blood therethrough, e.g. impedance plethysmography
• CPC Class Codes: A61B 5/6824 Arm or wrist
• CPC Class Codes: A61B 5/6829 Foot or ankle
• CPC Class Codes: A61B 5/7225 Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation A61B5/30, A61B5/316 take precedence; transformers for specific applications H01F38/00; amplifiers H03F
• CPC Class Codes: A61B 5/7246 using correlation, e.g. template matching or determination of similarity

Abstract

A first calculation unit receives phase characteristics Pa(f) and Pb(f) outputted from frequency transform units, calculates a propagation time difference based on a phase difference between the two phase characteristics in a high-frequency component thereof, and calculates a pulse wave velocity by dividing a difference in the distances of vascular pathways from the heart to respective measurement areas. Meanwhile, a second calculation unit calculates a pulse wave velocity by dividing the stated difference in the distances by a appearance time difference at a predetermined position in respective pulse waveforms obtained by rendering the measurement signals Pa(t) and Pb(t) on a time axis. A comparison unit compares the pulse wave velocities, and in the case where the ratio thereof is outside a predetermined range, an evaluation result indicating that it is possible that a predetermined pathologic change is present in the vascular pathway is outputted to a display processing unit.

Claims

1. A measurement apparatus comprising:

a first measurement unit, worn on a first measurement area of a measurement subject that corresponds to a body surface at an area to which blood travels from the heart through a first vascular pathway, for measuring a first pulse wave signal;

a second measurement unit, worn on a second measurement area of said measurement subject that corresponds to a body surface at an area to which blood travels from said heart through a second vascular pathway, for measuring a second pulse wave signal;

an extraction unit for extracting a predetermined frequency component from said first pulse wave signal and said second pulse wave signal;

a first propagation velocity evaluation unit for calculating, based on said extracted frequency component, a first pulse wave velocity in a first frequency that has been shown in advance not to be influenced by a predetermined pathologic change in said second vascular pathway;

a second propagation velocity evaluation unit for calculating, based on said first pulse wave signal and said second pulse wave signal, a second pulse wave velocity using a different method than said first propagation velocity evaluation unit; and

an output unit for outputting a degree to which said first pulse wave velocity and said second pulse wave velocity match.

2. The measurement apparatus according to claim 1,

wherein said first propagation velocity evaluation unit calculates said first pulse wave velocity based on a phase difference between said first pulse wave signal and said second pulse wave signal at said first frequency, said first frequency, and a difference between a distance from the heart to said first measurement area and a distance from said heart to said second measurement area.

3. The measurement apparatus according to claim 1,

wherein said second propagation velocity evaluation unit calculates said second pulse wave velocity based on a propagation time difference obtained by comparing a predetermined position in a pulse wave shape obtained by rendering said first pulse wave signal on a time axis with a predetermined position in a pulse wave shape obtained by rendering said second pulse wave signal on a time axis, and based on a difference between a distance from the heart to said first measurement area and a distance from said heart to said second measurement area.

4. The measurement apparatus according to claim 1,

wherein based on said frequency component extracted from said first pulse wave signal and said second pulse wave signal, said second propagation velocity evaluation unit calculates said second pulse wave velocity based on a phase difference in pulse waves in a second frequency that has been shown in advance to be influenced by said predetermined pathologic change in said second vascular pathway.

5. A measurement method comprising:

a step of measuring a first pulse wave signal at a first measurement area of a measurement subject that corresponds to a body surface at an area to which blood travels from the heart through a first vascular pathway;

a step of measuring a second pulse wave signal at a second measurement area of said measurement subject that corresponds to a body surface at an area to which blood travels from said heart through a second vascular pathway;

a step of extracting a predetermined frequency component from said first pulse wave signal and said second pulse wave signal;

a step of calculating, based on said extracted frequency component, a first pulse wave velocity in a first frequency that has been shown in advance not to be influenced by a predetermined pathologic change in said second vascular pathway;

a step of calculating, based on said first pulse wave signal and said second pulse wave signal, a second pulse wave velocity using a different method than the step of calculating said first pulse wave velocity; and

a step of outputting a degree to which said first pulse wave velocity and said second pulse wave velocity match.