Patent ID: 6413224
Filing Date: 2002-07-02
Classification: A61B

Abstract:
An apparatus for automatically measuring a blood pressure of a living subject, comprising:an inflatable cuff adapted to be wound around a body portion of the subject, said cuff being inflated to provide a cuff pressure to press said body portion; a pressure sensor which detects said cuff pressure; a pressure changing device which changes said cuff pressure; a blood pressure measuring device which measures a blood pressure value of the subject by reading said cuff pressure detected by said pressure sensor while the cuff pressure is decreased at a prescribed rate by said pressure changing device; a waveform detector which detects a waveform of a pulse wave produced in said cuff during the decreasing of said cuff pressure, said waveform of said pulse wave being changeable with said cuff pressure; determining means for determining a relationship between (A) evaluated values of a waveform of a pulse wave, (B) pressure values of said cuff, and (C) blood pressure values of the subject, based on (a) an evaluated value of said waveform of said pulse wave detected by said waveform detector, (b) a pressure value of said cuff at a time of detection of said waveform by said waveform detector, and (c) said blood pressure value of the subject measured by said blood pressure measuring device, said relationship being proper to the subject; estimating means for estimating, according to the determined relationship, a blood pressure values of the subject based on (aâ€²) an evaluated value of a waveform of a pulse wave detected by said waveform detector while said cuff pressure is increased before the cuff pressure is decreased at said prescribed rate in measuring an actual blood pressure subject and (bâ€²) a pressure value of said cuff at a time of detection of said waveform during the increasing of said cuff pressure; evaluating means for evaluating a plurality of characteristic values of said waveform of said pulse wave detected by said waveform detector during said decreasing of said cuff pressure, and providing an evaluated value of each of the waveform characteristics; and wherein said determining means determines a plurality of relationships each based on the evaluated value of a corresponding one of said waveform characteristics and said estimating means calculates a plurality of blood pressure values of the subject according to the determined relationships, respectively, and estimates said blood pressure value of the subject based on the calculated blood pressure values.