#6608 CHARACTERIZING THE RESIDUAL VOLUME IN PERITONEAL DIALYSIS PATIENTS

Abstract Background and Aims Peritoneal dialysis (PD) is the most common home treatment, associated with lower societal costs increased patient autonomy. During routine PD, exact amount of fluid inside peritoneal cavity in general unknown, catheter may also change position, which lead to a large residual volume, inefficient dialysis, potentially harmful overfill. A practical, clinical method estimate volume from dilution marker molecule before after fill known fresh fluid. However, ultrafiltration transport during phase introduce errors, especially when low molecular weight molecules are utilized. Method Here we performed retrospective analysis data consisting 56 estimations utilizing either 1.5% glucose (n = 28) or 4.25% 28). Residual volumes were estimated using creatinine, urea albumin. The contribution mass quantified Three-pore model. Results phase, median was 16 mL (IQR 3 31) dwells, compared 52 38 66) dwells (Fig. 1). Assuming that 40% occurs as free-water transport, difference between model albumin equation only -1 (-8 5.5) 1 (-3 6) 2A). Dilution-based calculations creatinine overestimated by 121 103 149) 255 208 323) (Figure 2B). Overestimation similar magnitude observed calculated Comparison intraperitoneal revealed increase 37% (creatinine) 48% (urea) phase. Conclusion This highlights inherent limitations molecules, both transfer influence results. Since rates correlate size, albumin-based conformed closely three-pore volumes, while urea, subject greater extent, volumes. Albumin superior but latter markers provide reasonable estimates, if purpose exclude volume.