Korean Journal of Nephrology 1996;15(3):392-402.

혈액 투석시 총 투석액 직접 측정법과 2회 투석액 표본 추출법을 이용한 Kt/Vurea의 비교

송영구 , 김흥수 , 김도현

Abstract

The blood-side Kt/Vurea based on the urea kine- tic model(UKM) is frequently influenced by a number of potential errors. On the other hand, the direct dialysate quantification(DDQ) methodology avoids many of these problems. However, the DDQ method is cumbersome and also difficult to incor- porate as a routine procedure. This study was done to see if total urea removed by dialysis and thus Kt/V, could be accurately estimated by two representative dialysate samples obtained at the beginning and the end of each dialysis session(two dialysate sample method, 2DSM). We compared the results obtained by 2DSM with those DDQ and Daugirdas' formula. 1) The rate of decrease in dialysate urea con- centration with time o@n dialysis could be described better by a logarithmic(R=0.997) than a linear func- tion (R=0.950). Therefore, the average dialysate urea concentration by 2DSM could be calculated by log mean of two dialysate samples obtained at the beginning and the end of each dialysis. 2) The average' dialysate urea concentration attai- ned by 2DSM was 14.74±6.93mg/dl, and that by DDQ was 15.30±6.69mg/dl (p=0.181), The total urea removed attained by 2DSM was 19.20±9.92g and that by DDQ was 19.84±9.81g (p=0.192). 3) The Kt/V, was 1.79±0.40 in DDQ and 1.80± 0.42 in 2DSM, and they did not show significant differences (p=0.139). But the Kt/V, by using Dau- girdas' formula<1.510.25) was significantly lower than the value obtained by using above two methods. However, when we used log mean of pre and post-dialysis BUN rather than mid-point BUN(Cm) in the equation of defining dialyzer urea clearance (K=UR/(CmXTd)), the Kt/Vurea showed no significant difference in the three methods(1.50 ± 0.26 in DDQ, 1.52±0.28 in 2DSM, 1.51±0.25 in Daugirdas' formula). In conclusion, the 2DSM is a new simple and accurate method to determine the total urea removed and thus Kt/V,. This new method avoids cumber- some and time consuming process of having to collect all the spent-dialysate in the DDQ method.