Załuska Wojciech T, Schneditz Daniel, Swatowski Andrzej, Jaroszyński Andrzej J, Ksiazek Andrzej
Department of Nephrology, Medical University, Lublin, Poland.
Med Sci Monit. 2003 Sep;9(9):CR405-10.
One of the uncertainties in the prescription of dialysis dose, measured as Kt/V for urea (Kt/Vu), is the volume of urea distribution (V). The aim of our study was to compare two different approaches to estimating V and Kt/V, respectively, and to compare the predicted (prescribed) dose with the actually delivered dose, measured by urea kinetics.
MATERIAL/METHODS: V was estimated using anthropometric measures with the Watson formula (VWatson), and also by multi-frequency bioimpedance analysis (VBIS). Both volumes were determined for the state at the end of dialysis and ultrafiltration, and then used to predict (prescribe) Kt/VWatson and Kt/VBIS, respectively. The delivered Kt/Vu was determined from pre- and postdialysis urea concentrations.
209 patients were studied in 254 measurements. VWatson and VBIS correlated significantly (VBIS=0.64*VWatson+15.03, r2=0.67) but VWatson (36.0 +/- 6.4 L) was higher than VBIS (32.5 +/- 8.1 L). The bias between techniques was 3.5 +/- 4.6 L. As a consequence of volume underestimation, Kt/VBIS was overestimated (1.44 +/- 0.38) when compared to the actually delivered Kt/Vu (1.28 +/- 0.32). However, Kt/VWatson (1.27 +/- 0.25) based on VWatson was almost identical to the actually delivered treatment dose.
The close correspondence between the delivered and predicted (prescribed) dose of dialysis using anthropometric volumes leads to the conclusion that in this study kinetic distribution volume was best described by VWatson. The overestimation of prescribed dialysis dose based on bioimpedance analysis suggests caution in the use of bioimpedance volumes, because of the risk of prescribing inadequate dialysis.
以尿素的Kt/V（Kt/Vu）衡量的透析剂量处方中的不确定因素之一是尿素分布容积（V）。我们研究的目的是分别比较两种不同的估算V和Kt/V的方法，并将预测（处方）剂量与通过尿素动力学测量的实际输送剂量进行比较。
材料/方法：使用人体测量指标通过沃森公式（VWatson）估算V，也通过多频生物电阻抗分析（VBIS）估算V。在透析和超滤结束时测定这两种容积，然后分别用于预测（处方）Kt/VWatson和Kt/VBIS。根据透析前后的尿素浓度确定实际输送的Kt/Vu。
对209例患者进行了254次测量。VWatson和VBIS显著相关（VBIS = 0.64×VWatson + 15.03，r2 = 0.67），但VWatson（36.0±6.4L）高于VBIS（32.5±8.1L）。两种技术之间的偏差为3.5±4.6L。由于容积被低估，与实际输送的Kt/Vu（1.28±0.32）相比，Kt/VBIS被高估（1.44±0.38）。然而，基于VWatson的Kt/VWatson（1.
