Methodology Study On Determination Of Vascular Access Recirculation In Hemodialysis

Hemodialysis(HD) is the main therapy for end-stage renal disease (ESRD) . Sufficiency of dialysis significantly affects survival and prognosis of HD-patients. Vascular access is the life line of patients on hemodialysis. Effective vascular access, including sufficient fistula blood flow, long-term patency and low morbidity, is therefore essential for HD therapy. However, the recycling process of HD often interferes with doctor's judgment and evaluation on the effectiveness of dialysis. Monitoring the function of vascular access regularly, finding any abnormity as soon as possible and providing appropriate intervention in time are important for prolonging service time of the vascular access [20l Urea test remains to be the most common test for determining access recirculation despite its limitation and difficulty. Although it is generally accepted that Kapoian's modified two-needle test is a preferable method because of its advantage of avoiding overrating the recirculation, three BUN concentrations are needed to confirm one AR; in addition, repetition and veracity of laboratory BUN test are poor, affecting its reliability[15]. Non-urea tests, including Doppler ultrasound test[16J, heat dilution test [17]and transducer method [18], are more accurate but very expensive, and thus are mostly used in scientific study rather for clinical use[15J. Finding a simple, effective and inexpensive method of determining vascular access recirculation has been the focus of study for many researchers.The present study aims to find a simple, convenient, effective and economic technique for determination of access recirculation in hemodialysis. The following is part of our completed research work: 1) Access recirculation was determined by urea test and glucose infusion test as was recommended by Magnasco A in 82 HD-patients. Self assessment of the patients revealed that there was a good correlation between the two methods; 2) Comparison of the GIT and urea test results using Doppler ultrasonography showed that the results of GIT were more accurate. The amount of access recirculation markedly increased in patients with arteriovenous stenosis. The screening test for vascular access recirculationis was an important way of screening A-V stenosis; 3) Measurements of body weight, UF, BP, KT/V, and QB demonstrated that there was a good correlationbetween GIT and the urea method. The results of the present study show that GIT is simpler, more sensitive and less costly than is urea test, warranting widespread use in clinical dialysis centers.