小児急性腎障害リスク患者におけるフロセミド負荷試験の使用

The furosemide stress test (FST) is used to assess urine flow rate (UFR) after a furosemide bolus. FST predicts severe acute kidney injury (AKI) and renal replacement therapy (RRT) receipt in adults, with limited data in pediatric intensive care unit (PICU) patients. We implemented AKI risk stratification using the renal angina index (RAI) with urine neutrophil gelatinase-associated lipocalin (uNGAL) to guide FST in high-risk children but have not evaluated outcomes.

We combined 2 prospective, observational studies of high AKI risk PICU patients (RAI+: ≥ 8, uNGAL+: ≥ 150 ng/ml). We compared patients who underwent FST (≥ 0.75 mg/kg i.v. furosemide) in the first week versus those who did not, and FST responders (≥ 3 ml/kg/h UFR over 4 hours) versus nonresponders. We examined UFR's predictive performance for new or persistent severe AKI or RRT receipt 2 days later.

Of 273 RAI+/uNGAL+ patients, 112 (41%) underwent FST, 60 (54%) were nonresponders. FST patients had higher admission uNGAL and AKI stage. Nonresponders received FST earlier, had higher AKI stage, and higher incidence of new or persistent severe AKI (89% vs. 37%, P < 0.001) and RRT receipt (43% vs. 8%, P < 0.001) 2 days later. UFR predicted new or persistent severe AKI (area under the receiver operating curve [ROC; AUROC]: 0.89; 95% confidence interval [CI]: 0.82-0.95, P < 0.001) with optimal cutoff < 4 ml/kg/h (positive predictive value [PPV]: 83%, negative predictive value [NPV]: 82%), and RRT receipt (AUROC: 0.84; 95% CI: 0.76-0.93, P < 0.001]) with optimal cutoff < 1 ml/kg/h (PPV: 68%, NPV: 86%). UFR predicted RRT receipt in patients with stage 3 AKI with similar test characteristics.

FST is used inconsistently in high AKI risk children but has prognostic utility for new or persistent severe AKI, including RRT receipt, independent of AKI stage.