Patent ID: 7079889
Filing Date: 2006-07-18
Classification: A61B

Abstract:
1. A living body impedance measurement apparatus, comprising: a voltage measurement unit; a separation unit; a calculation formula storage unit; a fluctuation constant calculation unit; a fluctuation constant storage unit; and a living body impedance calculation unit, wherein said voltage measurement unit measures a voltage attributed to an impedance of a living body or an external reference unit, or of a living body, an external reference unit or an internal reference unit, said separation unit separates the voltage attributed to the impedance as measured by said measurement unit into a voltage attributed to its resistance component and a voltage attributed to its reactance component, said calculation formula storage unit stores an impedance calculation formula therein in advance, said impedance calculation formula correlates a true impedance variable representing resistance component and reactance component of true impedance of the living body or the external reference unit with a fluctuation variable representing a fluctuation which may be caused in said voltage measurement unit due to any impedance change factor as well as a measured voltage variable representing the voltage attributed to resistance component and the voltage attributed to reactance component of an actually measured impedance, said fluctuation constant calculation unit calculates a fluctuation constant that is the constant for the fluctuation variable by substituting the voltage attributed to resistance component and the voltage attributed to reactance component, which are separated from each other by said separation unit, corresponding to the voltage attributed to the impedance of the external reference unit as measured by the voltage measurement unit, as well as the resistance component and the reactance component of the impedance of the external reference unit as measured by the voltage measurement unit for terms in said impedance calculation formula stored in said calculation formula storage unit in advance, said fluctuation constant storage unit stores the fluctuation constant calculated by said fluctuation constant calculation unit, and said living body impedance calculation unit calculates the resistance component and the reactance component of the true living body impedance by substituting the fluctuation constant stored in the fluctuation constant storage unit and the voltage attributed to the living body impedance as measured by the voltage measurement unit for the terms in said impedance calculation formula stored in said calculation formula storage unit in advance.