Impact of Postoperative Fluid Management Strategies on Outcomes and Graft Function After Pediatric Living‐Related Kidney Transplant

BACKGROUND: Fluid management postkidney transplantation in children varies significantly due to the lack of standardized guidelines. The replacement of urine output and timing of transition to fixed-rate fluid therapy depend on physician assessment and individual patient characteristics. OBJECTIVE: This study aimed to evaluate the impacts of different postoperative fluid management strategies, specifically the duration of urine output replacement and the timing of transition to a fixed rate, on early clinical outcomes and graft function within 28 days after living-related pediatric kidney transplantation. METHODOLOGY: This retrospective single-center cohort study includes pediatric living-related kidney transplant recipients admitted to the pediatric critical care unit (PICU) between November 2008 and March 2023. Based on the actual postoperative fluid management strategy documented in their charts, patients were categorized into three groups: (1) transition to a fixed-rate IVF within 48 h; (2) transition within 48 h with a 20%-30% deficit before fixed rate; and (3) prolonged 1:1 urine output replacement for ≥ 96 h before transition to a fixed rate. Clinical outcomes, including graft function, fluid overload, infectious complications, and length of stay, were compared among the three groups. RESULTS: A total of 113 were included in the final analysis. Significant variability in fluid management practices was observed among pediatric patients postkidney transplantation. All grafts survived, and short-term renal function was similar across the groups. However, compared to Groups 1 and 2, patients in Group 3 experienced significantly higher fluid overload (median 12%-16% vs. 4%-7%, p < 0.001), a higher incidence of pulmonary edema requiring mechanical ventilation (15% vs. 0%, p = 0.005), increased rate of urinary tract infection (35% vs. 8%-10%, p = 0.023), and bacteremia (20% vs. 0%-2%, p = 0.009), and a longer median PICU stay (7 days vs. 4-5 days, p = 0.003). CONCLUSION: In this retrospective cohort study, graft survival and short-term graft function were preserved across all groups regardless of the fluid management strategy. However, prolonged 1:1 UOP replacement beyond 96 h postoperatively was associated with increased fluid overload, more infectious complications, and longer PICU stay compared to earlier transition to fixed rate fluid therapy. These findings underscore the need for prospective randomized studies and standardized fluid management protocols to define the optimal postoperative fluid management strategies in pediatric kidney transplantation.