Bioimpedance-Guided Fluid Removal in Continuous Kidney Replacement Therapy: The VENUS Randomized Clinical Trial

Background: Ultrafiltration with continuous kidney replacement therapy (CKRT) can be used to manage fluid balance in critically ill patients with acute kidney injury (AKI). We aimed to assess whether bioimpedance analysis (BIA)-guided volume management was more efficacious than conventional management for achieving estimated euvolemia (e-euvolemia) in CKRT-treated patients. Methods: In a multi-center randomized controlled trial from July 2017 to July 2020, the patients with AKI requiring CKRT were eligible if the weight at the start of CKRT had increased by ≥5% compared to the weight at the time of admission, or total body water (TBW)/ height (H) 2 ≥13 L/m 2 . We randomly assigned 208 patients to the control (conventional fluid management; N=103) and intervention groups (BIA-guided fluid management; N=105). Primary outcome was the proportion of attaining e-euvolemia seven days post-randomization. E-euvolemia was defined as the difference between TBW/H 2 D 7 and D 0 was <–2.1 L/m 2 , or when TBW/H 2 measured on D 7 was <13 L/m 2 . The 28-, 60-, and 90-day mortality rate were secondary outcomes. Results: The primary outcome occurred in 34 patients in the intervention group and 27 in the control group (47% versus 41%; P =0.50). The mean value of TBW/H 2 measured on D 7 was the same at 13.9 L/m 2 in both groups. The differences between TBW/H 2 D 7 and D 0 were -1.13 L/m 2 in the intervention group and -1.08 L/m 2 in the control group ( P =0.84). Patients in the intervention group had a significantly higher proportion of reaching e-euvolemia on D 1 than those in the control group (13% versus 4%, P =0.02). Adverse events did not differ significantly between the groups. Conclusions: BIA-guided volume management did not affect the proportion of reaching the estimated euvolemia at seven days of the start of CKRT. Trial registration: ClinicalTrials.gov, ID: NCT03330626 (Registered on 6 November 2017; Seven study participants were retrospectively registered; nonetheless, IRB approval of each institution was completed before study participant registration).