Nadine Denneman1, Lara Hessels2, Bo Broens3, Jolijn Gjaltema3, Sandra N Stapel3, Julius Stohlmann3, Maarten W Nijsten2, Heleen M Oudemans-van Straaten3. 1. Department of Adult Intensive Care Medicine, Amsterdam UMC, VU University Medical Center, Amsterdam, The Netherlands. n.denneman@amsterdamumc.nl. 2. Department of Critical Care, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. 3. Department of Adult Intensive Care Medicine, Amsterdam UMC, VU University Medical Center, Amsterdam, The Netherlands.
Abstract
BACKGROUND: Bioelectrical impedance analysis (BIA) is a validated method to assess body composition in persons with fluid homeostasis and reliable body weight. This is not the case during critical illness. The raw BIA markers resistance, reactance, phase angle, and vector length are body weight independent. Phase angle reflects cellular health and has prognostic significance. We aimed to assess the course of phase angle and vector length during intensive care unit (ICU) admission, and determine the relation between their changes (Δ) and changes in body hydration. METHODS: A prospective, dual-center observational study of adult ICU patients was conducted. Univariate and multivariable regression analyses were performed, including reactance as a marker of cellular mass and integrity and total body water according to the Biasioli equation (TBWBiasioli) and fluid balance as body weight independent markers of hydration. RESULTS: One hundred and fifty-six ICU patients (mean ± SD age 62.5 ± 14.5 years, 67% male) were included. Between days 1 and 3, there was a significant decrease in reactance/m (-2.6 ± 6.0 Ω), phase angle (-0.4 ± 1.1°), and vector length (-12.2 ± 44.3 Ω/m). Markers of hydration significantly increased. Δphase angle and Δvector length were both positively related to Δreactance/m (r2 = 0.55, p < 0.01; r2 = 0.38, p < 0.01). Adding ΔTBWBiasioli as explaining factor strongly improved the association between Δphase angle and Δreactance/m (r2 = 0.73, p < 0.01), and Δvector length and Δreactance/m (r2 = 0.77, p < 0.01). CONCLUSIONS: Our results show that during critical illness, changes in phase angle and vector length partially reflect changes in hydration.
BACKGROUND: Bioelectrical impedance analysis (BIA) is a validated method to assess body composition in persons with fluid homeostasis and reliable body weight. This is not the case during critical illness. The raw BIA markers resistance, reactance, phase angle, and vector length are body weight independent. Phase angle reflects cellular health and has prognostic significance. We aimed to assess the course of phase angle and vector length during intensive care unit (ICU) admission, and determine the relation between their changes (Δ) and changes in body hydration. METHODS: A prospective, dual-center observational study of adult ICU patients was conducted. Univariate and multivariable regression analyses were performed, including reactance as a marker of cellular mass and integrity and total body water according to the Biasioli equation (TBWBiasioli) and fluid balance as body weight independent markers of hydration. RESULTS: One hundred and fifty-six ICU patients (mean ± SD age 62.5 ± 14.5 years, 67% male) were included. Between days 1 and 3, there was a significant decrease in reactance/m (-2.6 ± 6.0 Ω), phase angle (-0.4 ± 1.1°), and vector length (-12.2 ± 44.3 Ω/m). Markers of hydration significantly increased. Δphase angle and Δvector length were both positively related to Δreactance/m (r2 = 0.55, p < 0.01; r2 = 0.38, p < 0.01). Adding ΔTBWBiasioli as explaining factor strongly improved the association between Δphase angle and Δreactance/m (r2 = 0.73, p < 0.01), and Δvector length and Δreactance/m (r2 = 0.77, p < 0.01). CONCLUSIONS: Our results show that during critical illness, changes in phase angle and vector length partially reflect changes in hydration.
Authors: Isabel Cornejo-Pareja; Isabel M Vegas-Aguilar; Henry Lukaski; Antonio Talluri; Diego Bellido-Guerrero; Francisco J Tinahones; Jose Manuel García-Almeida Journal: Nutrients Date: 2022-06-30 Impact factor: 6.706