Monitoring dialysis efficacy by comparing delivered and predicted Kt/V.

Introduction. In Europe, especially in Germany, little is currently known about the relationship between urea kinetics delivered and predicted haemodialysis doses for patients on maintenance haemodialysis. We compared delivered and predicted Kt/V in patients of an outpa- Introduction tient dialysis centre in Berlin by calculating the ratio of delivered and predicted Kt/V, resulting in the eY- Comprehensive data from the United States Renal cacy quotient, Q E. Moreover, we studied the influence Data System ( USRDS ) provide evidence that morbidof technical and anthropometric parameters on both ity and mortality of patients with end-stage renal delivered Kt/V and Q E under routine clinical disease ( ESRD) are related to the amount of urea conditions. removed during haemodialysis (HD) [1]. Current Methods. Blood samples were taken after the long American guidelines [2] therefore place a strong interval in a thrice-weekly regimen before and 10 min emphasis on the use of Kt/V for the assessment of after ultrafiltration and 100 ml/min slow-pump dialysis adequacy. method. Delivered Kt/V was computed using the Apart from the general assessment of dialysis Daugirdas III formula. Predicted Kt/V was estimated adequacy, the Kt/V concept may also have considerfrom the dialysis filter urea clearance given by the able practical value for monitoring the technical eYmanufacturer, treatment time and the total body water cacy of dialysis in an individual patient. The aim of ( V ) computed by the Watson formula and was cor- the present study was therefore to examine the relationrected for real blood flow. As and when appropriate, ship between delivered Kt/ V( Kt/V del ) and predicted bivariate and multivariate regression analyses were Kt/ V( Kt/V pred ), expressed as an eYcacy quotient used to make comparisons. (Q E ), as a measure of technical performance. We Results. The mean quotient (Q E ) between delivered studied these parameters in a group of unselected and predicted Kt/V was 1.02±0.20. Mean delivered patients undergoing routine haemodialysis in an Kt/V in 377 treatments of 128 patients was 1.28±0.27. European outpatient dialysis unit in which dialysis Delivered Kt/V and Q E were positively associated dosage a priori was based on session time rather than (P<0.001). Q E was significantly associated with post- on Kt/V. HD urea, body mass index (BMI ) and sex, but not with session time. Significant positive predictors for delivered Kt/V were post-dialysis urea, sex, session Subjects and methods time, blood flow and kind of vascular access. BMI was inversely related to delivered Kt/V. Measurements were performed during routine dialysis sesDiscussion. In this study, the relationship between sions in all patients (n=127) undergoing chronic maintenance delivered and predicted Kt/ V( Q E ) was reproducible haemodialysis between February 1997 and March 1998 at and close to the ideal value of 1.0. In contrast to an outpatient clinic in Berlin, Germany. Following the long delivered Kt/V, Q E was not influenced by session time, interdialytic interval on a thrice-weekly schedule, blood and positively by BMI. Since Q E gives a valid meas- samples were drawn before starting UF and before removing ure of technical dialysis eYcacy we suggest the use the second needle. Samples were stored at 4°C and transferred to the laboratory after 4 to 12 h. Treatment was terminated of this parameter in addition to delivered Kt/ Vt o by re-infusing the blood of the venous line with a reduced monitor HD adequacy in clinical routine more blood flow of 100 ml/min using 150 ml 0.9% saline solution.