Bioimpedance-Guided Fluid Removal in Continuous KRT: The VENUS Randomized Clinical Trial

Key Points:

1. This study, the sole randomized trial of its kind, proposes guidelines for fluid balance management in continuous KRT (CKRT) patients using bioimpedance.

2. Despite this, bioimpedance analysis–guided volume management did not influence the proportion of patients achieving estimated euvolemia at 7 days into CKRT.

3. Further investigation is needed to assess whether bioimpedance analysis guidance can facilitate rapid fluid removal in the early phase of CKRT for patients with AKI.

Background: Ultrafiltration with continuous KRT (CKRT) can be used to manage fluid balance in critically ill patients with 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 multicenter 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 with the weight at the time of admission or total body water (TBW)/height (H)² ≥13 L/m². We randomly assigned 208 patients to the control (conventional fluid management; n=103) and intervention groups (BIA-guided fluid management; n=105). The primary outcome was the proportion of attaining e-euvolemia 7 days postrandomization. E-euvolemia was defined as the difference between TBW/H² D₇ and D₀ was <−2.1 L/m², or when TBW/H² measured on D₇ was <13 L/m². 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/H² measured on D₇ was the same at 13.9 L/m² in both groups. The differences between TBW/H² D₇ and D₀ were −1.13 L/m² in the intervention group and −1.08 L/m² in the control group (P = 0.84). Patients in the intervention group had a significantly higher proportion of reaching e-euvolemia on D₁ 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 e-euvolemia at 7 days of the start of CKRT.

Clinical Trial registry name and registration number:: ClinicalTrials.gov, ID: NCT03330626 (Registered on November 6, 2017; seven study participants were retrospectively registered; nonetheless, Institutional Review Board approval of each institution was completed before study participant registration).