Furosemide Stress Test for Evaluating Renal Recovery During Continuous Renal Replacement Therapy: A Protocol-Based Pilot Randomized-Controlled (FST-STOP) Trial

Background: The optimal timing for discontinuing continuous renal replacement therapy (CRRT) remains uncertain. There is limited data on the use of the furosemide stress test (FST) to assess recovery from renal tubular dysfunction. This study aimed to determine whether FST could facilitate earlier discontinuation of renal replacement therapy (RRT).Methods: Critically ill patients with stage 3 acute kidney injury (AKI) who had received CRRT for at least 48 hours were enrolled and randomized 1:1 to either a protocol-based FST (PB-FST) group or standard care. The primary outcome was successful RRT discontinuation.Results: Twenty-four patients were enrolled, with a mean age of 70.3±15.6 years and a median baseline estimated glomerular filtration rate (eGFR) of 57.5 mL/min/1.73 m² (interquartile range: 47.5–77). CRRT was successfully discontinued in 6 of 12 patients (50%) in the PB-FST group and 4 of 12 patients (33.3%) in the standard care group (P = 0.408). By day 2, urine output was 990 mL/day in the PB-FST group compared to 372.5 mL/day in the standard care group (P = 0.299); by day 5, it increased to 1427.5 mL/day and 932.5 mL/day, respectively (P = 0.386).Conclusions: PB-FST may be feasible for assessing renal recovery during CRRT. However, the small sample size may limit the statistical power of the findings.