Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA.
Departments of Medicine, VA Palo Alto HCS and Stanford University, 3801 Miranda Ave, Palo Alto, CA, 94304, USA.
Pediatr Nephrol. 2020 Feb;35(2):305-312. doi: 10.1007/s00467-019-04369-6. Epub 2019 Nov 14.
Dialysis in children as well as adults is prescribed to achieve a target spKt/V, where V is the volume of distribution of urea. Waste solute production may however be more closely correlated with body surface area (BSA) than V which rises in proportion with body weight. Plasma levels of waste solutes may thus be higher in smaller patients when targeting spKt/V since they have higher BSA relative to body weight. This study measured levels of pseudouridine (PU), a novel marker solute whose production is closely proportional to BSA, to test whether prescription of dialysis to a target spKt/V results in higher plasma levels of PU in smaller children.
PU and urea nitrogen (ureaN) were measured in plasma and dialysate at the midweek hemodialysis session in 20 pediatric patients, with BSA ranging from 0.65-1.87m. Mathematical modeling was employed to estimate solute production rates and average plasma solute levels.
The dialytic clearance (K) of PU was proportional to that of ureaN (average K/K 0.69 ± 0.13, r 0.84, p < 0.001). Production of PU rose in proportion with BSA (r 0.57, p < 0.001). The pretreatment plasma level of PU was significantly higher in smaller children (r 0.20, p = 0.051) while the pretreatment level of ureaN did not vary with size.
Prescribing dialysis based on urea kinetics may leave uremic solutes at higher levels in small children. Measurement of a solute produced proportional to BSA may provide a better index of dialysis adequacy than measurement of urea.
在儿童和成人中都规定了透析，以达到目标 spKt/V，其中 V 是尿素分布容积。然而，废物溶质的产生可能与身体表面积 (BSA) 更密切相关，而 V 则与体重成比例增加。因此，当以 spKt/V 为目标时，较小患者的血浆废物溶质水平可能更高，因为他们的 BSA 相对于体重更高。本研究测量了假尿嘧啶核苷 (PU) 的水平，一种新型标记溶质，其产生与 BSA 成正比，以测试将透析设定为目标 spKt/V 是否会导致较小儿童的血浆中 PU 水平更高。
在 20 名儿科患者的每周三次血液透析治疗的中间周测量血浆和透析液中的 PU 和尿素氮 (ureaN)，BSA 范围为 0.65-1.87m。采用数学模型估算溶质产生率和平均血浆溶质水平。
PU 的透析清除率 (K) 与 ureaN 的透析清除率成正比（平均 K/K 0.69±0.13，r 0.84，p<0.001）。PU 的产生与 BSA 成正比（r 0.57，p<0.001）。较小儿童的预处理血浆 PU 水平显著较高（r 0.20，p=0.051），而预处理尿素 N 水平与体型无关。
基于尿素动力学的透析可能会导致较小儿童的尿毒症溶质水平更高。测量与 BSA 成正比产生的溶质可能比测量尿素更能提供更好的透析充分性指标。
