| 摘要 |
<p>PURPOSE:To permit the blood pressure measurement with high prevision by properly detecting the degree of the blood flow obstruction in the cuff pressure variation process even in the case where the judgment of the Korotkoff sound is difficult, by measuring the arterial blood flow state as the variation of the electric impedance in the cuff pressure variation process. CONSTITUTION:An electromagnet driving circuit 8 excites an electromagnet 7 by the AC synchronized with the high frequency constant current, and an eddy current is applied from the electromagnet 7 to a part where the constant current supplied from a high frequency constant current source 4 flows. As for the current distribution, the electric current of the electromagnet 7 is feedback-driven so that the constant current projection part-eddy currents in equal phase strengthen each other on the A side, while the phase deflects and said electric currents weaken each other on the B side, and the electric current of the electromagnet 7 is feedback-driven so that the output supplied to a pair of electrodes 11 becomes always zero on the B side. Accordingly, the electric current I1 exists only on the A side. In this state, a voltage Vn=I1R is observed on a pair of detection electrodes 10 on the A side, and the output proportional to the resistance value R in tissue is obtained. When the decompression of a cuff 1 proceeds and the blood flow of a radius artery is restarted, the reduction of the resistance value R is observed, according to the degree of filling the artery with the blood having the small specific resistance.</p> |
