| Summary: | 碩士 === 義守大學 === 生物醫學工程學系碩士班 === 99 === Incidence and prevalence of renal failure in adult Taiwanese with 45 or greater years led the whole world. As reported, there are more than 50,000 patients who are receiving dialysis in Taiwan, with most patients in the southern area. As the number of patients undergoing hemodialysis increases in Taiwan, the same increment has also been observed in the incidence of hemodialysis access dysfunction and this has lead to significance of the role of percutaneous transluminal angioplasty in these lesions.
Thus, in the thesis a device for measuring the blood flow sound in the graft or fistula was developed. Fifty patients with vessel access dysfunction in the Cardiovascular Center of the Kaohsiung Veteran Hospital were included in the study, and their blood flow sound at three different positions of the fistula or graft were respectively recorded using the measuring device before and after angioplasty. The frequency spectra of the blood flow sound signals were obtained with the Fast Fourier Transform. Energy ratio corresponding to each frequency band (1-10, 10-100, 100-200, 200-300, 300-600, 600-800 and 800-1000 Hz) was further used to make a comparison between before and after the angioplasty. Results showed that there was a trendency to be different in the energy ratios at the frequency band of 800-1000 Hz in the blood flow sound between before and after the angioplasty (p=0.082). On the basis of the angioplasty positions, the energy ratios at 300-600, 600-800 and 800-1000 Hz before the angioplasty were significantly different from those after the surgery (p=0.007, p=0.021, p=0.009). Furthermore, there were linear relationships between the energy ratios at 800-1000 Hz frequency band and the pulse pressure in the graft or fistula before the angioplasty (r=0.61), and the difference in the pulse pressure before and after the surgery (r=0.66). Thus, the recorded blood flow sound may be used to indirectly assess the stenotic severity of the fistula or graft. This method may become a useful diagnosis way for early and non-invasive evaluation of the stenosis situation in the hemodialysis patients.
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