Abstract
Fluid management after kidney transplantation requires balancing adequate graft perfusion against fluid overload. We compared central venous pressure (CVP)-guided and point-of-care ultrasound (POCUS)-guided postoperative management and explored whether longitudinal changes in inferior vena cava (IVC) diameter relative to an individual postoperative reference provided information beyond absolute IVC diameter. This single-center retrospective comparative study included 60 adult kidney transplant recipients (30 per group) with standardized assessments on postoperative days 1–5 and 10. POCUS-guided management was associated with more active therapeutic adjustments during days 1–5 (48.0% vs. 25.3%; OR 2.80, 95% CI 1.45–5.42; p = 0.002), without a significant difference in cumulative fluid balance. Reference IVC diameter ranged from 7 to 21 mm and showed substantial interindividual variability. Within-patient IVC variation was associated with daily fluid balance (p = 0.002) and weight change (p = 0.003). In a post hoc exploratory ROC analysis, peak baseline-referenced ΔIVC showed an AUC of 0.749 (95% CI 0.574–0.924) for >1 kg postoperative weight gain, compared with 0.518 (95% CI 0.300–0.737) for peak absolute IVC; the two AUCs were not formally compared. No statistically significant between-group differences in early graft outcomes were observed, although the study was not powered for these outcomes. POCUS-guided monitoring was associated with greater treatment actionability; whether this translates into clinical benefit requires prospective evaluation.