Comparison of fluid volume estimates in chronic hemodialysis patients by bioimpedance, direct isotopic, and dilution methods

Kidney Int. 2014 Apr;85(4):898-908. doi: 10.1038/ki.2013.358. Epub 2013 Sep 25.

Abstract

Bioimpedance analysis (BIA) is accepted for the assessment of total-body water (TBW), intracellular fluid (ICF) and extracellular fluid (ECF). We aimed to compare precision and accuracy of single and multi-frequency-BIA to direct estimation methods (DEMs) of TBW, ECF, and ICF in hemodialysis patients. Linear regression analysis of volume estimates in 49 patients by single- and multi-frequency-BIA correlated significantly with DEMs. Bland-Altman analysis (BAA) found systemic bias for ECF single-frequency-BIA vs. ECF-DEMs. No other systematic biases were found. Proportional errors were found by BAA of ICF and ECF assessments with single- and multi-frequency bioimpedance spectroscopy compared to the DEMs. Comparisons of indirect methods (IEMs) to DEMs showed no significant differences and proportional errors. Root mean-squared-error analysis suggested slightly better accuracy and precision of ICF single-frequency-BIA vs. DEMs over ICF multi-frequency-BIA and IEMs to DEMs, and slightly better performance for ECF multi-frequency-BIA over both respective other methods. Compared to DEMs, there is slightly better accuracy for ECF multi- over single-frequency-BIA and ICF single- over multi-frequency-BIA. However the margin of differences between direct and indirect methods suggests that none of the analyzed methods served as a true "gold standard", because indirect methods are almost equally precise compared to DEMs.

Publication types

  • Clinical Trial
  • Comparative Study

MeSH terms

  • Adult
  • Aged
  • Body Fluids*
  • Bromides
  • Deuterium Oxide
  • Electric Impedance
  • Female
  • Humans
  • Indicator Dilution Techniques
  • Kidney Failure, Chronic / physiopathology
  • Kidney Failure, Chronic / therapy
  • Male
  • Middle Aged
  • Renal Dialysis
  • Sodium Compounds

Substances

  • Bromides
  • Sodium Compounds
  • Deuterium Oxide
  • sodium bromide