Continuous measurement of circulating blood hematocrit using conduction catheter

循环血液的红细胞压积不仅表示红细胞体积占总血液体积的分数，而且还表示循环血液体积的动态变化。使用微量滴定法测量红细胞压积值需要大约5-10分钟。然而，血容量有时在几秒钟内变化。结果：1）研制了一种新型的循环血红细胞压积连续测量导管; 2）研制了一种血液阻抗和电导的计算机在线测量系统; 3）研究了红细胞压积与血液阻抗和电导的关系，红细胞压积与血液电导有良好的线性关系; 4）研制了一种新型的循环血红细胞压积连续测量导管，并在清醒犬体内进行了试验。该方法在清醒动物中的应用包括以下技术问题。a）血液流速影响血液电导。B）导管与血管壁接触后，血液电导发生变化，上述问题有待进一步研究。

Hematocrit of circulating blood indicates not only a fraction of red blood cell volume to total blood volume but also dynamic changes in circulating blood volume. To measure a value of hematocrit, it takes about 5-10 min using micro centrifuging method. However, blood volume change sometime in seconds. Therefore, It is worth to d, Relop a continuous measurement of circulating blood hematocrit.Results :1)New implantable catheter for continuous measurement of circulating blood hematocrit has been developed2)On-line system for measurement of blood impedance and conductance using computer has been made.3)Relationship between hematocrit and blood impedance and conductance were studied.There was good linear relationship between hematocrit and blood conductance.4)'Ibe new catheter for the continuous measurement of circulating blood hematocrit was tested to use in conscious dogs. This method include following technical problems to use in conscious animal. a) Blood flow rate affect blood conductance. b) Blood conductance changed if the catheter touched to the vascular wall.Obviously, further study is needed to solve above problems.