Timing of Renal Replacement Therapy in Acute Kidney Injury After Liver Transplantation: The Value of NMF Standards

Objective To evaluate the utility of the NMF standards—comprising intraoperative norepinephrine dosage, preoperative MELD-Na score, and total intraoperative fluid intake—in determining the optimal timing for initiating renal replacement therapy (RRT) in patients with acute kidney injury (AKI) following liver transplantation. Methods This study developed the NMF standards and an associated WeChat mini-program. Feasibility was validated through two cohorts: a retrospective study (2018–2023, 189 KDIGO stage 2 AKI patients) and a prospective study (2024–2025, 76 NMF-guided vs. 189 clinician-judged controls). Primary endpoints included postoperative creatinine, MELD-Na, blood ammonia, hospital stay, CKD incidence, and long-term RRT dependency. Results The NMF standards were validated as a robust clinical tool: intraoperative norepinephrine ≥ 6.5 µg·kg ^− 1 ·h ^− 1 , preoperative MELD-Na ≥ 15.5, and total fluid intake ≥ 6600 mL. Retrospectively, NMF-compliant patients receiving timely RRT exhibited significantly improved postoperative creatinine (64.5 vs. 72.2 µmol/L), MELD-Na, and blood ammonia levels, shorter hospital stays (24 vs. 27.5 days), and reduced risks of CKD (14.5% vs. 24.5%) and long-term RRT (7.9% vs. 18.5%) compared to controls. Prospective validation confirmed these trends, with lower 7-day creatinine (64.5 vs. 72.2 µmol/L), MELD-Na, and blood ammonia, shorter stays (24 vs. 27.5 days), and decreased CKD (14.5% vs. 24.5%) and long-term RRT (7.9% vs. 18.5%). Conclusions The NMF standards, integrated with a user-friendly WeChat mini-program, provide a validated framework for optimizing RRT timing in AKI post-liver transplantation. This tool enhances clinical decision-making, reduces complications, and improves long-term renal outcomes.