Absolute blood volume variations during hemodialysis: Does dialysate temperature play a role?

Abstract

Background: Vascular refilling occurs to preserve hemodynamic stability during hemodialysis (HD). Recent studies report a feasible and noninvasive method to determine absolute blood volume (ABV), and estimate vascular refilling during HD. The objective of this study is to analyze if lowering dialysate temperature modifies variations in ABV during HD. Methods:The study was performed in 50 patients under HD. During two different sessions, relative blood volume was assessed using dialysate temperatures of 35.5°C (cool dialysate) and 36.5°C (neutral dialysate). ABV and vascular refilling were calculated using Kron et al methodology.Results: Thirty-nine intradialytic morbid events (IMEs) were observed in 30 patients, 14 under cool dialysate and 25 during neutral dialysate. We did not found statistically differences in ABV or in refilling volume between cool and neutral temperature.When analyzing apart only those patients who presented IME, we observed lower drop in ABV in the 35.5°C dialysate treatments (0.57 L) versus 36.5°C dialysate treatments (0.71 L). When cool dialysate was used, the vascular refilling fraction tended to be higher, but data did not turn statistically significant. Conclusions:In selected groups of patients the use of cool dialysate induces lower ABV variations that could improve hemodynamic stability during HD treatments.

Dynamics of vascular refilling in extended nocturnal hemodialysis

“…Recently, we developed a method to determine absolute blood volume during routine HD sessions 11,12 . This offered the possibility to quantify vascular refilling in different clinical settings 10,13–15 …”

Vascular refilling depends on the ratio of blood volume to extracellular volume in hemodialysis patients

“…In previous clinical studies on vascular refilling, the refilling fractions reached a mean level of about 70-75% with relatively large individual variability (SD about ± 10%, or even individually minimum 40 and maximum 98%). 4,6,10,11,[13][14][15][16][17][18][19] In theory, the sum of refilling fraction and BV/ECV ratio should be 1. 11 However, we could not confirm this hypothesis in this study (sum 1.07).…”

Impact of dialysate sodium concentration on vascular refilling

“…30 A recently published study has also shown that, in a selected group of patients, the use of cool dialysate (35.5 C) may reduce ABV drop during HD treatments. 31 However, further studies are needed to understand how different hemodialysis parameters modify ABV drop or F ref and minimize IME.…”