On a Circulation System Monitor of HD Patient to Realize a Safe High Efficiency Dialysis (1992)

为了实现安全而高效的血液透析，不可避免地要了解患者的状态，以避免由于快速除水而导致的压力下降。本课题主要开发了两个监测系统。一个是连续的血容量。血氧饱和度监测仪，连续测量。为此，设计了一对756和805 nm激光的光电探测电路.已知805 nm的光束对血红蛋白的氧饱和度不敏感，血红蛋白的氧饱和度测量所谓的血细胞比容。应根据红细胞压积连续计算相对血容量。756射束对氧饱和度敏感，结合805射束数据可以测量氧饱和度，而血压的连续测量是本研究中遇到的另一个急需解决的问题，因为血液透析患者的血压会突然下降。本文在分析血液循环系统等效电路的基础上，提出了一种新的方法。分析结果给出了透析回路中测得的压力与肱动脉压之间的简单关系。为了将这一结果应用于临床，我们设计了一种新的透析回路，其中包括一个附加的空气阱，临床试验在有效性和无创性方面是可以接受的。

To realize a safe but high efficiency hemodialysis, it is inevitable to know the patient state to avoid pressure drops due to the rapid water removal. Mainly two monitor systems were developed in this research projects. One is a continuous blood volume and. oxigen saturation monitor which measures continuously. For this sistem a couple of laser photodetecting circuit including the beams of 756 and 805 nn. 805 nm beam is known to be insensitive to oxigen saturation degree of hemoglobin, which in tern measures the so called heamatocrit. From the heamatocrit relative blood volume shall be calculated continuously. 756 beam is sensitive to the oxigen saturation so as to measure the saturation degree with the conbination of of 805 beam data.Continuous measurement of blood pressure is the other of urgent problem whi we encountered in this research, because of sudden pressure drops in hemodialysis patients. Based on analysis with an electric equivalent circuit of blood circulation system, a new approach has been developed here. The result of analysis gave a simple relation between pressure measured at dialysis circuit and the brachial pressure. To put this result into a clinical use, a new dialysis circuit vas designed, which include an additional air-trap.The clinical test were fairly acceptable in usefulness and noninvasive.