Continuous monitoring of sodium concentration in blood during haemodialysis by a selective membrane and conductivity sensor

Abstract

The aim of this study is to monitor sodium concentration in patients' blood suffering from chronic uraemia in order to improve their comfort and dialysis efficiency. After the study of the membrane device geometry in order to obtain the fastest response time and to reduce the pressure drop in the device placed on an extracorporeal blood line of haemodialysis, we have analyzed several hydrodynamic conditions. We finally succeeded in obtaining a protein retention larger than 99% and a sodium transfer from bovine blood of 100%. During ultrafiltration of blood (retentate), we have induced a sodium-concentration variation in retentate and obtained a good correlation between the filtrate solution conductivity and the sodium concentration in blood, in transient conditions.