A noninvasive sphygmomanometer capable of obtaining an accurate blood pressure value is provided without complicating a structure and with little time-consuming work. A photointerrupter 31, a wave-shaping circuit 75, a rotation number counting circuit 77, and a discharge amount calculating circuit 78 which measure a discharge amount of a pressure pump 13, and an arm circumference length detecting circuit 79 which calculates an arm circumference length of a subject person based on a relationship between a pressure in a bladder 8 provided in an armband 9 and the measured discharge amount of the pressure pump 13 is provided. Then, a blood pressure value is corrected based on the calculated arm circumference length.
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation application of application Ser. No. 10/682,816 filed Oct. 10, 2003 now U.S. Pat. No. 7,008,739, which claims the priority of Japanese Patent Application No. 2002-324867 filed Nov. 8, 2002. The disclosure of the above-referenced patent applications, as well as that of each US and foreign patent and patent application identified in the specification of the present application, is incorporated herein by reference.
In blood pressure measurement of a vertebrate through use of an inflatable pressure cuff disposed about a limb of the vertebrate limb and inflated by pump driven by a motor, the air pressure within the cuff is determined at any given time during the inflation of the cuff by calculating the incremental change in pressure in the pressure cuff over a series of small time increments and summing the calculated incremental pressure changes from the initiation of cuff inflation to a desired point in time during the inflation of the pressure cuff. The incremental change in pressure within the cuff is calculated as a function of the incremental change in current drawn by the pump motor over the time increment.
