Evaluation of fluid balance and dry weight with BIA in patients with maintenance hemodialysis

Abstract

Objective: To evaluate the fluid balance and dry weight with whole body bioelectrical impedance analysis (BIA) in patients with maintenance hemodialysis (MHD). Methods: Twenty patients in stable condition with MHD for more than one year were selected (MHD group). Extra-cellular water (ECW) and intra-cellular water (ICW) were measured by BIA before hemodialysis, after hemodialysis and at intervals of hemodialysis (24 h and 48 h after hemodialysis), and related parameters were calculated. Whether patients with MHD achieved dry weight at 0 h was analysed, and die effects of average daily urine volume on ECW and ICW were explored. Another 20 healthy volunteers were served as controls. Results: Compared with control group, ECW retrieved by ideal body weight was significantly higher before hemodialysis in MHD group (P < 0.05). In MHD group, ECW was significantly lower after hemodialysis than that before hemodialysis (P < 0.05). ECW/total body water (TBW) was significantly lower and ICW/TBW was significantly higher after hemodialysis than those before hemodialysis and at intervals of hemodialysis (P < 0.05). ICW and ECW at each time point were significantly related to body weight. ICW and ECW retrieved by ideal body weight at 0 h and 24 h of those who achieved dry weight were significantly higher than those who did not achieve dry weight (P <0.05). ECW and ICW Ijefore hemodialysis and 24 h after hemodialysis were significantly lower in those with urine volume <400 mL/d than those widi urine volume ≥400 mL/d (P <0.05). Conclusion: BIA analysis indicates that changes of fluid balance before hemodialysis, after hemodialysis and at intervals of hemodialysis in patients widi MHD are characterized by ECW, and ECW/TBW is a more sensitive parameter. ICW and ECW retrieved by ideal body weight may be sensitive parameters to determine the dry weight in patients with MHD.