Application of Microcontroller on Optimal Dialysis

• Main Authors: Shi-Xiang Yan, 顏士翔
• Other Authors: Yen-lin Chang
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/7sa3uf

碩士 === 中原大學 === 醫學工程研究所 === 91 === For the patients receiving long-term hemodialysis treatment, the disequilibrium syndromes during the dialysis process, that might eventually imperil their lives, and always been the most disturbing problem. The so-called disequilibrium syndrome refers to the epiphenomenoms during the dialysis treatment, including nausea, vomiting, headache, dizziness, convulsion, hypotension or hypertension. Theoretically, the reasons for such complication can be attributed to the prompt decrease in density of extracellular fluid that solutes during dialysis, while is far below the density of intercellular fluids. In recent years, Doc. Lee and Doc. Chang have employed a method of higher accuracy Two-Pool Model, and introduced a new concept of optimal dialysis. By controlling blood flow rate or dialysate flow rate step by step, patients receive the dialysis treatment while the density between extracellular and intercellular fluids is maintained at a lower level. This method has been obtained by preliminary clinical evidence, and our research center has been committed to the development of optimal dialysis systems. A complete set of software for blood dialysis treatment have been tested and proven effective both on theoretical and clinical simulations, and the primal prototype of dialysis machine central monitor/control system have also been optimized by our research center. This research upgrade the original design of blood dialysis center's central monitor/control system. It replaces computer with Micro- controller for playing a role to control dialysis machine. In the beginning, inputting the patient’s physiological parameters to the software of dialysis treatment, which is designed by our laboratory. After simulating of software, it shows the patient’s ideal blood flux or dialysate flux, and the microcontroller accepts computer’s signals (outputted by print port) and writes it to EEPEOM on the storage-card. After storing, then disconnecting and inserting storage-card into controlling-module. Microcontroller will outputs signals and transforms into voltage by DAC. After digital/analog converting, control dialysis machine pumps; at this time, 12 bits DAC (ADS7842E) converts output signal voltage to digital signal. In comparison with digital signal to the original digital, while the error is huge and can’t be ignored, then proceed to compensate for error until satisfying the object of optimal dialysis. The circuit and firmware on the storing-module and controlling-module has been finished. After test, the error on output of blood-flux is less than –7.4 ml/min. The error is acceptable on dialysis machine, which is need to be less ±10 ml/min in an adjustment.