Design and Implementation of Dialysate Temperature Control System for Hemodialysis: A Pilot Study

摘要

In hemodialysis, the control of body temperature by altering the dialysate temperature would reduce the intradialytic complications. Several studies show that the constant dialysate temperature affects the patient's quality of life due to their different temperature threshold. Thus, these factors serve as a motivation factor to design an individualized dialysate temperature control for hemodialysis patients, which can actively control the body temperature even in the case of any external disturbances. In this paper, a novel dialysate proportioning model has been proposed. Then, initial implementation of proposed model was designed with fuzzy logic control and implemented on a low-cost microcontroller—Raspberry Pi 3. A Simulink model was also designed by incorporating fuzzy logic control to implement in real time. The pumps' flow rates are varied using Pulse Width Modulation (PWM) according to the controller signal, while the temperature sensors are placed to acquire actual temperature in this model. Subsequently, it has been tested and verified by comparing the simulation and experimental results. Furthermore, the dialysate temperature trend was studied for various input conditions to analyze its controller behavior in real-time implementation. The results showed the potential to develop robust control by optimizing the fuzzy rules and membership functions. The system response time is found to be minimal (less than 300 ms), and the performance error is acceptable (less than 0.55%). Further work is ongoing to implement the dialysate temperature controller incorporating in vitro studies.