#4261 RELATIONSHIP BETWEEN FLUID OVERLOAD AND AVERAGE PLASMA REFILL RATE IN HEMODIALYSIS PATIENTS

Abstract Background and Aims Attaining the optimal balance between achieving adequate volume removal while preserving organ perfusion remains challenging in patients on maintenance hemodialysis (HD). Quantification of fluid status using bioimpedance spectroscopy (BIS) has become routine many countries. Inadequate vascular space refill from interstitial tissue (plasma rate, PRR) is main contributing factor hemodynamic instability during HD. We aimed to explore association overload (FO) plasma rate (PRR) chronic HD patients. Method Pre-HD FO [l] was assessed once per subject by BIS (Body Composition Monitor; Fresenius Medical Care) four urban dialysis clinics U.S. For each treatment within 30 days before after measurement, we calculated respective pre-HD assuming that differences body weight were equivalent FO. then used intradialytic hematocrit (measured with Crit-Line® Monitor, ultrafiltration data quantify average PRR, normalized (Wang et al. Kidney360, 2023): To calculate starting blood (BV), first ending BV Nadler equation, followed back-calculating based cumulative change relative BV. Plasma as sum changes volume; divided time estimated clinical dry PRR [ml/kg/hr]. Results analyzed 746 sessions 79 (age 61 ± 15 years; 52 (66%) males; 41 (52%) black 33 (42%) white). Across all sessions, positively associated [slope estimate 0.92 (95% confidence interval 0.83 1.02) ml/kg/hr 1 l FO, P value < 0.0001] (Figure 1). This also case subgroup analyses depleted (r = 0.94, P<0.001), normohydrated 1.03, P<0.0001), overloaded subjects 0.83, P<0.0001). Conclusion entire spectrum, depletion overload, higher (overall, an increase for additional liter FO). While greater would be expected better tolerate rates, there large inter-individual variability PRR. Further investigation utility throughout may offer novel insights into management symptom mitigation.