IntroductionClinical effects of Furosemide (F) and ethacrynic acid (EA) continuous infusion on urine output (UO), fluid balance and renal, cardiac, respiratory and metabolic function were compared in infants undergoing surgery for congenital heart diseases.MethodsA prospective randomized double-blinded study was conducted. Patients received either 0.2 mg/kg/h (up to 0.8 mg/kg/h) of F or EA.ResultsIn total 38 patients were enrolled in the F group and 36 in the EA group. No adverse reactions were recorded. UO at post-operative day (POD) 0 was significantly higher in the EA group, 6.9(3.3) ml/kg/h, compared to the F group, 4.6(2.3) ml/kg/h (P¿=¿0.002) but tended to be similar in the two groups thereafter. Mean administered F dose was 0.33(0.19) mg/kg/h compared to 0.22(0.13) mg/kg/h of EA (P <0.0001). Fluid balance was significantly more negative in the EA group at post-operative day 0: ¿43(54) ml/kg/h versus ¿17(32) ml/kg/h in the F group (P¿=¿0.01). Serum creatinine, Cystatin C and Neutrophil Gelatinase Associated Lipocalin levels and incidence of acute kidney injury did not show significant differences between groups. Metabolic alkalosis occurred frequently (about 70% of cases) in both groups but mean bicarbonate level was higher in the EA group: 27.8(1.5) mmol/L in the F group versus 29.1(2) mmol/L in the EA group (P¿=¿0.006). Mean cardiac index (CI) values were 2.6(0.1) L/min/m2 in the F group compared to 2.98(0.09) L/min/m2 in the EA group (P¿=¿0.0081). Length of mechanical ventilation was shorter in the EA group, 5.5(8.8) days compared to the F group, 6.7(5.9) (P¿=¿0.06). Length of Pediatric Cardiac Intensive Care Unit (PCICU) admission was shorter in the EA group: 14(19) days compared to 16(15) in the F group (P¿=¿0.046).ConclusionsIn cardiac surgery infants, EA produced more UO compared to F on POD 0. Generally, less EA dose is required to achieve similar UO than F. EA and F were safe in terms of renal function but EA caused a more intense metabolic alkalosis. EA patients achieved better CI, shorter mechanical ventilation and PCICU admission time.Trial registrationClinicaltrials.gov NCT01628731. Registered 24 June 2012.