PROBLEM TO BE SOLVED: To allow a fluid pressure to be measured without influencing flow of fluid in a tube used for artificial dialysis treatment.SOLUTION: An ultrasonic measuring device 1 performs the following steps of: transmitting an ultrasonic wave to a blood circuit tube 5 and calculating an inner diameter R serving as an index value indicating elastic deformation of the blood circuit tube 5 on the basis of a reception signal of a reflection wave thereof and utilizing an internal pressure change amount Δp and an inner diameter change amount ΔR having a proportional relationship, calculating the internal pressure change amount Δp on the basis of a change amount ΔR with respect to an inner diameter initial value R0 of the inner diameter R and calculating an internal pressure p (namely, a venous pressure) of the blood circuit tube 5 by adding the internal pressure change amount Δp to the internal pressure initial value p.COPYRIGHT: (C)2015,JPO&INPIT【課題】人工透析治療に用いられるチューブ内の流体の流れに影響を与えることなく、流体圧を計測可能とすること。【解決手段】超音波計測装置1は、超音波を血液回路チューブ5に送信し、その反射波の受信信号に基づいて、血液回路チューブ5の弾性変形を示す指標値である内径Rを算出する。そして、内圧変化量Δpと内径変化量ΔRとは比例関係にあることを利用し、この内径Rの内径初期値R0に対する変化量ΔRをもとに内圧変化量Δpを算出し、内圧初期値pに内圧変化量Δpを加算することで、血液回路チューブ5の内圧p(すなわち静脈圧)を算出する。【選択図】図1
