Primerjava ultrazvočnega merjenja premera spodnje votle vene in merjenja sestave telesa z metodo bioelektrične impedance za oceno tekočinskega stanja pri novorojenčkih

Abstract

Background: Neonatal medical conditions often disrupt the physiological processes that regulate fluid balance, so assessing fluid status in sick neonates is important for clinical management. In clinical practice we use clinical signs, which, however, on their own, do not provide a reliable assessment of fluid status. We aimed to compare two methods: i) diameters and collapsibility index of vena cava inferior (VCI) measured by ultrasonography and ii) analysis of body composition by bioelectrical impedance (BIA) and to evaluate their relation to changes in body mass. Methods: In a cohort-prospective clinical trial we included 27 neonates aged 1–7 days with various pathologies. Ultrasound measurements of VCI transversely and longitudinally, measurements of body composition by BIA and measurements of body mass were performed in each subject at least three times with an interval of 24–72 hours. Simultaneous measurements of the same subject were then analysed and evaluated. Results: The average proportion of total body water (TBW) decreased in the first days after birth, from 80.3% (Day 1) to 73.1% (Day 8) (p = 0.006). The decrease in the average proportion of extracellular water (ECW) in the first days after birth was not statistically significant. The association between ECW and body mass over time was statistically significant (p < 0.001). The association between transversely measured large VCI diameter during inspiration, body mass, and ECW was statistically significant (p = 0.024). No statistically significant association with ECW or body mass was proven for the other ultrasound-measured variables. Conclusions: By measuring body composition with BIA, we confirmed the reduction of the average proportions of TBW after birth and the association between body mass, ECW, and transversely measured maximal diameter of VCI during inspiration. BIA is an appropriate method for monitoring fluid status in a newborn. Additional research on a larger number of subjects is needed to define the significance of VCI measurements for assessing fluid status.