Design and Implementation of a Capacitance Based Air Bubble Detection System for Hemodialysis Machine

摘要

Hemodialysis is one of the medical treatment methods for the patients with end stage renal disease. It is conducted through the use of artificial kidney, located outside of the human body. During the hemodialysis therapy, small air bubbles may infiltrate the blood tubing and coalesce to perform the larger bubble which can be harmfull for the patient if entering the patient's blood circulatory system. The objective of this work is to develop an capacitance based air bubble detection system for hemodialysis machine. The research method covers conceptual design, detail design, prototyping and performance testing for the capacitance sensor as well as the data acquisition system. The validation test was conducted to verify the functionality of the system. For testing purposes, an experimental setup was constructed and several test runs were conducted. Comparison between measurement conducted using capacitance technique and using ultrasonic technique was also presented in this work. It shows that close agreement between the results obtained using ultrasonic technique and capacitance technique is observed in this work.