Applying bio-impedance vector analysis (BIVA) to adjust ultrafiltration rate in critically ill patients on continuous renal replacement therapy: A randomized controlled trial

J Crit Care. 2022 Dec:72:154146. doi: 10.1016/j.jcrc.2022.154146. Epub 2022 Sep 15.


Background: Bioimpedance vector analysis (BIVA) has been suggested as a valuable tool in assessing volume status in critically ill patients. However, its effectiveness in guiding fluid removal by continuous renal replacement therapy (CRRT) has not been evaluated.

Methods: In this randomized controlled trial, 65 critically ill patients receiving CRRT were allocated on a 1:1 ratio to have UF prescribed and adjusted using BIVA fluid assessment in the intervention group (32 patients) or conventional clinical parameters (33 patients). The primary outcome was the lean body mass (LBM) water content at CRRT discontinuation, and the secondary outcomes included the mortality rate, urinary output, the duration of ventilation support, and ICU stay.

Results: The study group was associated with a lower water content of LBM (80.7 ± 9.4 vs. 85.9 ± 10.4%; p < 0.05), and a higher mean UF-rate and urinary output (1.5 ± 0.8 vs. 1.2 ± 0.5 ml/kg/h and 0.9 ± 0.9 vs 0.5 ± 0.6 ml/kg/h, both: p < 0.05). The mortality rate, the length of ICU stay, and ventilation support duration were similar.

Conclusion: BIVA guided UF prescription may be associated with a lower rate of fluid overload. Larger studies are required to evaluate its impact on patients' outcomes.

Keywords: AKI; BIVA; Bio-impedance; CRRT; Critical illness; Fluid overload; Ultrafiltration rate.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Acute Kidney Injury* / therapy
  • Continuous Renal Replacement Therapy*
  • Critical Illness / therapy
  • Electric Impedance
  • Humans
  • Intensive Care Units
  • Prospective Studies
  • Renal Replacement Therapy
  • Ultrafiltration
  • Water


  • Water