Biological information measuring apparatus

Abstract

A biological information measuring apparatus (10) includes a compression belt (20) to be wound around a part of a living body, a pressure adjusting unit (51) configured to change an internal pressure of the compression belt, a data acquiring unit (52) configured to acquire time-series data indicating a change in each of the internal pressure of the compression belt and a capacity of the compression belt in a period in which the internal pressure of the compression belt is changing, and a tonus-information calculating unit (53) configured to calculate, based on the time-series data, tonus information indicating a correspondence relation between a first indicator indicating pressure applied to a blood vessel wall (100) of the living body and a second indicator indicating a capacity on an inner side of the blood vessel wall.

1 . A biological information measuring apparatus comprising:
 a compression belt to be wound around a part of a living body;   a pressure adjusting unit configured to change an internal pressure of the compression belt;   a data acquiring unit configured to acquire time-series data indicating a change in each of the internal pressure of the compression belt and a capacity of the compression belt in a period in which the internal pressure of the compression belt is changing; and   a tonus-information calculating unit configured to calculate, based on the time-series data, tonus information indicating a correspondence relation between a first indicator indicating pressure applied to a blood vessel wall of the living body and a second indicator indicating a capacity on an inner side of the blood vessel wall, wherein   the tonus-information calculating unit calculates, as a fluctuation width of the second indicator, a fluctuation width of the capacity of the compression belt that fluctuates according to a beat of a heart, and calculates the tonus information using the fluctuation width, and   the tonus-information calculating unit creates a first formula that is a formula of an envelope passing the time-series data acquired at timing at respective peaks of a pulsation in a graph representing a relation between the internal pressure and the capacity and a second formula that is a formula of an envelope passing the time-series data acquired at timing at respective bottoms of the pulsation in the graph representing the relation between the internal pressure and the capacity and calculates the fluctuation width corresponding to each of the internal pressures by subtracting a value obtained by the second formula from a value obtained by the first formula.   
     
     
         2 . The biological information measuring apparatus according to  claim 1 , wherein a value of the second indicator corresponding to each of values of a plurality of the first indicators is included in the tonus information calculated by the tonus-information calculating unit. 
     
     
         3 . (canceled) 
     
     
         4 . The biological information measuring apparatus according to  claim 1 , wherein the tonus-information calculating unit integrates, for the internal pressure of the compression belt, a compliance value, which is a gradient of a change of the second indicator corresponding to the change in the internal pressure of the compression belt, up to a predetermined value to calculate a value of the second indicator corresponding to the predetermined value. 
     
     
         5 . The biological information measuring apparatus according to  claim 4 , wherein
 when a maximum value of an internal pressure of the compression belt for not closing the inner side of the blood vessel wall even when the heart expands and blood pressure is minimum is represented as a first pressure and a minimum value of an internal pressure of the compression belt for closing the inner side of the blood vessel wall when the heart contracts and the blood pressure is maximum is represented as a second pressure,   the tonus-information calculating unit calculates each of the first pressure and the second pressure in advance and, then, in a range in which the internal pressure of the compression belt is smaller than the first pressure, calculates the compliance value by dividing the fluctuation width of the second indicator by a value obtained by subtracting the first pressure from the second pressure and, in a range in which the internal pressure of the compression belt is larger than the first pressure and smaller than the second pressure, calculates the compliance value by dividing the fluctuation width of the second indicator by a value of the second pressure.   
     
     
         6 . The biological information measuring apparatus according to  claim 5 , wherein the tonus-information calculating unit calculates each of the first pressure and the second pressure based on a correspondence relation between the internal pressure of the compression belt and the fluctuation width of the capacity of the compression belt. 
     
     
         7 . The biological information measuring apparatus according to  claim 1 , further comprising an output unit configured to output the tonus information.