Patent ID: 6913575
Filing Date: 2005-07-05
Classification: A61B

Abstract:
1. A blood pressure measuring apparatus, comprising: an inflatable cuff including a first inflatable bag adapted to be worn on a body portion of a living subject so as to exclude blood from an artery located in the body portion, and a second inflatable bag adapted to be worn on the body portion, on a distal side of a middle portion of the first inflatable bag, so as to detect a pulse wave produced from the artery; a first piping which is connected to the first inflatable bag; a second piping which is branched from the first piping and is connected to the second inflatable bag; a pump which supplies an inflating fluid to the first and second inflatable bags via the first and second pipings, respectively; a blood pressure determining device which determines a blood pressure of the subject based on the pulse wave detected through the second inflatable bag when a pressing pressure of the first inflatable bag is changed; and a switching device which is provided in the second piping and which selectively switches the second piping to a connected state in which the second piping is connected to the first piping and to a disconnected state in which the second piping is disconnected from the first piping; pressure determining device includes: an amplitude correcting means for correcting at least one of (a) respective first amplitudes of respective heartbeat-synchronous pulses of a first pulse wave detected through the first inflatable bag when the pressing pressure of the first inflatable bag is decreased in a blood-flow stopping pressure range in which a flow of blood in the artery is stopped, and (b) respective second amplitudes of respective heartbeat- synchronous pulses of a second pulse wave detected through the second inflatable bag when the pressing pressure of the first inflatable bag is decreased in the blood-flow stopping pressure range, so that each of the corrected amplitudes is substantially equal to a corresponding amplitude of the other of (a) the first amplitudes and (b) the second amplitudes; an amplitude-difference determining means for determining an amplitude difference between said each of the corrected amplitudes and said corresponding amplitude of the other of (a) the first amplitudes and (b) the second amplitudes, so that the determined amplitude differences show a rising point; and a blood pressure determining means for determining a systolic blood pressure of the subject based on the rising point of the amplitude differences determined by the amplitude-difference determining means.