Measurement of Fluid Status Using Bioimpedance Methods in Korean Pediatric Patients on Hemodialysis

Abstract

Adequate fluid management is an important therapeutic goal of dialysis. Recently, bioelectrical impedance methods have been used to determine body fluid status, but pediatric reports are rare. To determine the accuracy of bioelectrical impedance methods in the assessment of body fluid statusof children undergoing hemodialysis (HD), 12 children on HD were studied. A multi-frequency bioimpedance analysis device (Inbody S10) and bioimpedance spectroscopy device (BCM) were used to evaluate fluid status. Fluid removal during a HD session (assessed as body-weight change, ΔBWt) was compared with the difference in total body water determined by each device (measured fluid difference, ΔMF), which showed strong correlation using either method (Pearson's coefficient, r = 0.772 with Inbody S10 vs. 0.799 with BCM). Bioimpedance measurement indicated fluid overload (FO; ΔHS greater than 7%) in 34.8% with Inbody S10 and 56.5% with BCM, and only about 60% of children with FO by bioimpedance methods showed clinical symptoms such as hypertension and edema. In some patients with larger weight gain Inbody S10-assessed overhydration (OH) was much smaller than BCM-assessed OH, suggesting that BCM is more relevant in estimating fluid accumulation amount than Inbody S10. To our knowledge, this is the first report on the use of body composition monitors to assess fluid status in Korean children receiving HD.

Keywords: Bioimpedance; Children; Fluid Status; Hemodialysis.

Fig. 1

Correlation between the differences in MF state before and after HD and weight changes over HD. MF = measured fluid, HD = hemodialysis, ΔBWt = body-weight changes, ΔMF = difference in measured fluid state before and after HD.

Fig. 2

Agreement between the differences in MF state before and after HD and weight changes over HD. The solid line is the mean differences, and the dashed horizontal lines represent the two standard deviations of the differences. MF = measured fluid, HD = hemodialysis, ΔBWt = body-weight changes, ΔMF = difference in measured fluid state before and after HD, TBW = total body water, SD = standard deviation.

Fig. 3

Comparison of difference between clinically calculated OH and bioimpedance measured OH. OH = overhydration.

Fig. 4

Hydration status according to symptoms. Scatter graph shows the degree of ΔHS according to clinical symptoms in enrolled patients. FO (ΔHS greater than 7%) denoted by the yellow color box and severe FO (ΔHS greater than 15%) denoted by green box. FO = fluid overload, ΔHS = hydration status, HT = hypertension, E = edema.