Patent ID: 6428482
Filing Date: 2002-08-06
Classification: A61B

Abstract:
An apparatus for non-invasively estimating a waveform of a blood pressure in a central artery of a living subject, comprising:a pressure-pulse-wave detecting device which includes a pressure-pulse-wave sensor adapted to be pressed, via a skin of the subject, against a first portion of a peripheral artery located on a downstream side of the central artery and which non-invasively detects, through the pressure-pulse-wave sensor, a pressure pulse wave produced from the first portion of the peripheral artery; a blood-pressure-difference determining means for determining, according to a predetermined vascular-system model, a blood-pressure difference between a blood pressure at the first portion of the peripheral artery pressed by the pressure-pulse-wave sensor and a blood pressure at an end of the peripheral artery, based on the pressure pulse wave detected by the pressure-pulse-wave detecting device; a peripheral-artery-blood-pressure-waveform estimating means for estimating, based on the pressure pulse wave detected by the pressure-pulse-wave detecting device and the blood-pressure difference determined by the blood-pressure-difference determining means, a waveform of a forward pressure pulse wave at the first portion of the peripheral artery pressed by the pressure-pulse-wave sensor, and a waveform of a backward pressure pulse wave at the first portion of the peripheral artery; a propagation-time determining means for determining a propagation time in which the pressure pulse wave propagates from a second portion of the central artery to the first portion of the peripheral artery; and a central-artery-blood-pressure-waveform estimating means for estimating, based on the respective waveforms of the forward and backward pressure pulse waves estimated by the peripheral-artery-blood-pressure-waveform estimating means and the propagation time determined by the propagation-time determining means, a waveform of a forward pressure pulse wave at the second portion of the central artery and a waveform of a backward pressure pulse wave at the second portion of the central artery, and estimating a waveform of a blood pressure at the second portion of the central artery, by adding the respective estimated waveforms of the forward and backward pressure pulse waves at the second portion of the central artery.