University of Illinois College of Medicine, Chicago, Illinois 60612, USA.
Kidney Int. 2010 Apr;77(7):637-44. doi: 10.1038/ki.2009.525. Epub 2010 Jan 27.
Standard Kt/V(urea) (stdKt/V) is a hypothetical continuous clearance in patients treated with intermittent hemodialysis based on the generation rate of urea nitrogen and the average predialysis urea nitrogen. Previous equations to estimate stdKt/V were derived using a fixed-volume model. To determine the impact of fluid removal as well as residual urea clearance on stdKt/V, we modeled 245 hemodialysis sessions (including conventional 3/week, in-center 6/week, and at-home nocturnal 6/week) in 210 patients enrolled in the Frequent Hemodialysis Network Daily and Nocturnal clinical trials. To examine the role of fluid removal, modeled stdKt/V was compared to stdKt/V estimated from a previously published simplified equation. In a subgroup of 45 sessions with residual urea clearance over 1.5 ml/min, the contribution of residual urea clearance to stdKt/V was measured. For all dialysis schedules, the fixed-volume equation predicted stdKt/V well when both fluid removal and residual urea clearance were set to zero. When fluid removal was included, modeled stdKt/V was slightly underestimated for all three modes of hemodialysis. The shortfall correlated directly with weekly fluid removal and inversely with modeled urea volume. Modeled stdKt/V compressed residual urea clearance to about 70% of its measured value and the fractional downsizing significantly correlated inversely with treatment Kt/V. Our new equation predicted modeled stdKt/V with a high level of accuracy, even when substantial fluid removal and residual urea clearance were present.
标准 Kt/V（尿素）（stdKt/V）是一种基于尿素氮生成率和平均透前尿素氮的间歇性血液透析患者的假设连续清除率。之前用于估计 stdKt/V 的方程是使用固定体积模型推导出来的。为了确定液体清除以及残留尿素清除对 stdKt/V 的影响，我们对参加 Frequent Hemodialysis Network Daily 和 Nocturnal 临床试验的 210 名患者的 245 次血液透析治疗进行了建模（包括常规每周 3 次、中心每周 6 次和家庭夜间每周 6 次）。为了检查液体清除的作用，我们将模型化的 stdKt/V 与之前发表的简化方程估计的 stdKt/V 进行了比较。在具有 1.5ml/min 以上残留尿素清除的 45 次治疗中，测量了残留尿素清除对 stdKt/V 的贡献。对于所有透析方案，当液体清除和残留尿素清除均设置为零时，固定体积方程很好地预测了 stdKt/V。当包括液体清除时，所有三种血液透析模式的模型化 stdKt/V 均被低估。这种不足与每周的液体清除直接相关，与模型化的尿素量成反比。模型化的 stdKt/V 将残留尿素清除压缩到其测量值的约 70%，并且分数缩小与治疗 Kt/V 呈显著的负相关。即使存在大量的液体清除和残留尿素清除，我们的新方程也能高度准确地预测模型化的 stdKt/V。
