Patent ID: 8568328

Claim:
An electronic sphygmomanometer to measure blood pressure in accordance with the volume compensation method, the electronic sphygmomanometer comprising: a cuff adapted for attaching to a measurement site of the blood pressure, wherein the measurement site is selected from the group consisting of: a site from a wrist to a base of an arm, and a site from an ankle to a base of a leg; a pressure detector to detect a cuff pressure representing a pressure inside the cuff; a volume detector provided in the cuff and intended to detect an arterial volume signal indicating a volume of an artery of the measurement site; a cuff pressure adjustment unit to adjust the cuff pressure by increasing and decreasing the pressure; and a control unit comprising: a servo control unit to servo-control the cuff pressure adjustment unit so that the volume of the artery becomes constant, based on the detected arterial volume signal after setting the cuff pressure to the initial cuff pressure; a volume change detector to detect an amount of change in the volume of the artery prior to constant volume, based on the detected arterial volume signal, while the control by the servo control unit is being performed, a first control unit comprising: a control target value detector to detect a control target value by controlling the cuff pressure adjustment unit until the cuff pressure becomes a specific pressure at which the volume change detector detects that the amount of volume change in the volume of the artery is maximum, wherein the control target value is a maximum value of the amount of change in the volume of the artery; and a cuff pressure setting unit to set the cuff pressure to an initial cuff pressure representing the specific pressure value; an amplitude ratio detector to detect a ratio between an amplitude of the arterial volume signal detected when the cuff pressure is set to the initial cuff pressure representing the specific cuff pressure, that is, when the volume change detector detects that the amount of change in the volume of the artery is maximum, and an amplitude of the arterial volume signal detected when the volume change detector detects that the amount of change in the volume of the artery is minimal; and an output unit to output the ratio of the amplitude detected by the amplitude ratio detector as a barometer of a degree of arteriosclerosis.