Apparatus for measuring blood flow velocity and blood flow volume in aortas

摘要

A cuff (200) is put around an upper arm and a blood flow shutting bag (220) thereof shuts the blood flow at the upper arm. A forward detection bag (210) is disposed upstream and a rear detection bag (230) is disposed downstream of the blood flow shutting bag. A forward sensor (110) and a rear sensor (120) are provided to detect pressures in these bags. The sensors respectively detect a forward pulse wave (Wf) and a rear pulse wave (Wb). A reference internal pressure of the cuff is controlled by an air pump (140) and a leak valve (150) controlled by a CPU (130). The pulse waves are monitored to retain the reference internal pressure at a systolic pressure SP and a diastolic pressure DP. A propagation velocity of a pulse wave clearing the cuff retained at the systolic pressure SP can be given based on a delay time SPdt of the rear pulse wave with respect to the forward pulse wave. This propagation velocity is approximate to a blood flow velocity VH of the aorta in a high pressure period. A blood flow velocity VL in a low pressure period is given by dividing the blood flow velocity VH by a set coefficient R. A pulse wave obtained when the reference internal pressure is retained at the diastolic pressure DP is an approximate aortic wave. Based on this approximate aortic wave, blood flow effective sectional areas SH, SL are given.