Measuring fluid balance in end-stage renal disease with a wearable bioimpedance sensor

Accurate assessment of fluid volume and hydration status is essential in many disease states, including patients with chronic kidney disease. The aim of this study was to investigate the ability of a wearable continuous bioimpedance sensor to detect changes in fluid volume in patients undergoing regular hemodialysis (HD). 31 patients with end-stage renal disease were enrolled and monitored with a sensor patch (Re:Balans ) on the upper back through two consecutive HD sessions and the interdialytic period between. The extracellular resistance R was calculated from multi-frequency bioimpedance measurements and was hypothesized to correlate with the amount of extracted fluid during dialysis. Only HD sessions with a positive net fluid extraction were included in the primary analysis. Participants had an increase of 7.5 ± 4.3 Ω (Ohm) in R during the first HD and 6.2 ± 2.3 Ω during the second HD, and a fluid extraction (ultrafiltration (UF) volume) of 1.5 ± 0.8 L and 1.2 ± 0.6 L, respectively. The relative change in R during HD correlated strongly with UF volume (r = 0.82, p