Rationale & Objectives

Conventional monitoring of hemodialysis dose is implemented using urea kinetic modeling based on single-pool Kt/V, which requires both pre- and postdialysis serum urea nitrogen (SUN) measurements. We compared this conventional approach to one in which Kt/V is calculated using conductivity clearance, thereby reducing the need for regular postdialysis SUN measurements.

Study Design

Comparative study of 2 diagnostic tests.

Setting & Participants

Prevalent patients receiving maintenance hemodialysis for at least 2 years for whom both urea reduction ratio (URR) and average conductivity clearance (Kecn) were measured.

Tests Compared

During the initial 8 months (baseline interval), average Kecn and URR were used to calculate a median patient-specific, modeled, calibration solute distribution volume (Vcal). During months 9 to 16 (period 1) and 17 to 24 (period 2), Kt/V was conventionally computed using URR and also by a new method using Vcal and Kecn without postdialysis SUN values. We examined the percentage error between these 2 methods of calculating Kt/V.

Outcomes

Concordance between the 2 methods of calculating Kt/V.

Results

Among 1,093 patients, mean individual-level median single-pool Kt/V values derived using the conventional method during the baseline interval, period 1, and period 2 were 1.62 ± 0.24 (SD), 1.66 ± 0.24, and 1.67 ± 0.24, respectively. During periods 1 and 2, patient-level median Kt/V values derived using Kecn were 1.64 ± 0.24 and 1.65 ± 0.24, respectively. Percent differences between patient-level median values of Kt/V (conductivity minus conventional URR methods) were −0.63% ± 7.7% and −0.75% ± 8.4% for periods 1 and 2. Normalized protein nitrogen appearance were comparable between the 2 methods.

Limitations

Data were collected over 2 years. Study was limited to in-center hemodialysis patients dialyzed 3 times per week. Dialysis session length was not adjusted for treatment interruptions.

Conclusions

A new method of calculating Kt/V based on Kecn that requires fewer postdialysis SUN measurements provided diagnostic data comparable to those from conventional use of URR and has the potential to avoid errors related to postdialysis blood sampling and measurement.

中文翻译：

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常规Kt / V和归一化蛋白质氮的出现率是由不经常透析后血清尿素氮测量的电导率清除率确定的。

基本原理和目标

使用基于单池Kt / V的尿素动力学模型对血液透析剂量进行常规监测，这需要在透析前后对血清尿素氮（SUN）进行测量。我们将这种传统方法与使用电导率间隙计算Kt / V的方法进行了比较，从而减少了定期透析后SUN测量的需要。

学习规划

2种诊断测试的比较研究。

设置与参与者

接受维持性血液透析至少2年的流行患者，其尿素减少率（URR）和平均电导率清除率（Kecn）均已测量。

测试比较

在最初的8个月（基线间隔）内，平均Kecn和URR用于计算患者特定的，建模的校正溶质分布体积（Vcal）的中位数。在第9到16个月（第1阶段）和第17到24个月（第2阶段）期间，Kt / V通常是使用URR计算的，也可以通过使用Vcal和Kecn的新方法来计算，而没有透析后的SUN值。我们检查了这两种计算Kt / V的方法之间的百分比误差。

结果

两种计算Kt / V的方法之间的一致性。

结果

在1,093名患者中，在基线间隔，第1阶段和第2阶段使用常规方法得出的平均个人水平单池Kt / V值分别为1.62±0.24（SD），1.66±0.24和1.67±0.24。 。在第1和第2阶段，使用Kecn得出的患者水平Kt / V值中位数分别为1.64±0.24和1.65±0.24。在第1和第2阶段，患者水平Kt / V中位数之间的百分比差异（电导率减去常规URR方法）为-0.63％±7.7％和-0.75％±8.4％。

局限性

收集了2年的数据。研究仅限于每周透析3次的中心血液透析患者。透析疗程的长度未针对治疗中断进行调整。

结论

一种基于Kecn的Kt / V计算新方法，该方法需要较少的透析后SUN测量，所提供的诊断数据可与常规使用URR的诊断数据相媲美，并且有可能避免与透析后血液采样和测量相关的误差。