Abstract
OBJECTIVES: To investigate the effects of different filtration fractions (FFs) during continuous venovenous hemodiafiltration (CVVHDF) post-dilution. METHODS: This study employed a single-blind, head-to-head randomized controlled design. Patients who underwent daytime continuous renal replacement therapy (CRRT) in the Department of Nephrology, the Second Affiliated Hospital of Nanchang University between April 2022 and June 2023 were prospectively enrolled. They were randomly assigned to either a low FF group (FF set at 20%-<25%) or a high FF group (FF set at 25%-30%). All patients received post-dilution CVVHDF with systemic heparin anticoagulation. The primary outcome was extracorporeal circuit coagulation, comprehensively assessed through dynamic monitoring of arterial pressure, venous pressure, and transmembrane pressure, combined with filter clotting grading at the end of the session. Secondary outcomes included changes in serum creatinine, urea, potassium, and pH levels before and after treatment to evaluate efficacy. RESULTS: A total of 40 patients were included in both the low FF group and the high FF group. The baseline characteristics showed no statistically significant differences between the two groups (all P>0.05). All patients completed the treatment successfully, with a treatment duration of 10-12 h, and no filters required replacement during the sessions. The differences in arterial pressure, venous pressure, and transmembrane pressure at 2 h, 6 h, and the end of treatment compared to values at 1 h showed no statistically significant differences between the groups (all P>0.05). Furthermore, no significant differences were found in filter clotting grades (including grade Ⅰ and grade Ⅱ clotting) at the end of treatment between the two groups (both P>0.05). The creatinine clearance was significantly higher in the high FF group compared to the low FF group (P<0.01). However, the changes in blood urea nitrogen, serum potassium and pH levels before and after treatment showed no statistically significant differences between the groups (all P>0.05). CONCLUSIONS: For patients with a relatively short treatment duration of 10-12 h undergoing post-dilution CVVHDF, employing an FF of 25%-30% does not pose a higher risk of extracorporeal circuit coagulation compared to an FF of 20%-<25%, but shows higher creatinine clearance.