Mussnig Sebastian, Krenn Simon, Waller Max, Schmiedecker Michael, Kurnikowski Amelie, Niknam Saeidi Janosch, Naar Luis, Mayer Christopher C, Keane David, Schneditz Daniel, Hecking Manfred, Pstras Leszek
Medical University of Vienna, Center for Public Health, Department of Epidemiology, Vienna, Austria.
Medical University of Vienna, Department of Medicine III, Division for Nephrology and Dialysis, Vienna, Austria.
Clin Kidney J. 2025 Jun 27;18(8):sfaf199. doi: 10.1093/ckj/sfaf199. eCollection 2025 Aug.
Patients on maintenance hemodialysis accumulate excess fluid between treatments. Intradialytic removal of fluid via ultrafiltration is partly compensated by vascular refilling from the interstitial space. Associations between whole-body fluid status and blood volume were previously investigated on the population level. The aim of this observational cohort study was to assess longitudinal changes in fluid compartment volumes on an intra-patient level.
Pre-dialysis bioimpedance spectroscopy measurements and absolute blood volume estimations were conducted in maintenance hemodialysis patients during 14 consecutive dialysis treatments over 5 weeks. Blood volume was determined using the dialysate bolus method. Longitudinal changes were evaluated using linear mixed models. Correlations were analyzed with repeated measures correlation coefficients ([Formula: see text]).
Twenty-five patients were included in the final analysis [88% male, median (quartile 1, quartile 3) age and dialysis vintage of 66.0 years (48.0, 74.0) and 23.5 months (13.5, 34.5), respectively]. Pre-dialysis fluid overload significantly decreased from the first to the third treatment within the week ( = -0.38, < .01) with no significant within-week changes in euvolemic body mass (= -0.04, = .78) or absolute blood volume at treatment start ( = -0.06, = .65). Fluid overload did not correlate with absolute ([Formula: see text] = 0.10, = .65) or specific blood volume ([Formula: see text]=0.06, = .78) at treatment start on an intra-patient level, but correlated moderately with refilling volume ([Formula: see text] = 0.46, < .01).
The observed lack of intra-patient correlations between pre-dialysis fluid overload and blood volume suggests that excess fluid may not necessarily accumulate proportionally in the interstitial and intravascular space, thus challenging previous assumptions regarding within-week changes in fluid compartments.
维持性血液透析患者在两次治疗期间会蓄积过多液体。透析期间通过超滤清除的液体部分会由间质空间的血管再充盈来补偿。此前已在人群层面研究了全身液体状态与血容量之间的关联。这项观察性队列研究的目的是在个体患者层面评估液体腔室容积的纵向变化。
在5周内连续进行14次透析治疗期间，对维持性血液透析患者进行透析前生物电阻抗光谱测量和绝对血容量估计。使用透析液推注法测定血容量。使用线性混合模型评估纵向变化。采用重复测量相关系数（[公式：见原文]）分析相关性。
最终分析纳入了25例患者[男性占88%，年龄中位数（四分位数1，四分位数3）为66.0岁（48.0，74.0），透析龄中位数为23.5个月（13.5，34.5）]。透析前液体超负荷在一周内从第一次治疗到第三次治疗显著降低（= -0.38，<0.01），而等容体重（= -0.04，=0.78）或治疗开始时的绝对血容量在一周内无显著变化（= -0.06，=0.65）。在个体患者层面，治疗开始时液体超负荷与绝对血容量（[公式：见原文]=0.10，=0.65）或比血容量（[公式：见原文]=0.06，=0.78）无相关性，但与再充盈量呈中度相关（[公式：见原文]=0.46，<0.01）。
观察到透析前液体超负荷与血容量之间缺乏个体患者相关性，这表明过多液体不一定会按比例蓄积在间质和血管内空间，从而对先前关于一周内液体腔室变化的假设提出了挑战。
