Comparison of the furosemide dose titration in the first day of treatment for decompensated chronic heart failure using urine output or urine sodium concentration monitoring

Aim. To compare the efficacy and safety of furosemide dose titration during the first 24 hours of treatment for decompensated heart failure (HF) with fluid retention, based on either urine volume or spot urinary sodium concentration.Material and methods. This prospective, randomised, open-label, single-center study included 110 patients with decompensated HF, signs of fluid retention, and regular furosemide use. The initial intravenous furosemide dose was twice the outpatient dose. In the first group (n=55), efficacy was assessed by 6-hour urine output: if ≥100 mL/h, the same dose was repeated after 12 hours; if response was insufficient, the dose was doubled every 6 hours until the target urine volume was achieved. In the second group (n=55), the 2-hour spot urinary sodium concentration was used: if ≥50 mmol/L, the same dose was repeated after 12 hours; if <50 mmol/L, the dose was doubled every 6 hours until target natriuresis was reached. After 24 hours, if urine output was <3.5 L with persistent congestion, the last furosemide dose was repeated as a bolus twice daily with the addition of acetazolamide 500 mg/day for 3 days. If the response remained insufficient after 48 hours, hydrochlorothiazide 25 mg/day was added without changing the furosemide dose. For urine output between 3.5 and 5 L, the furosemide dose was unchanged; for output >5 L with signs of congestion, the dose was halved. Once congestion resolved, patients were switched to oral furosemide.Results. Mean patient age was 74±9.2 years; male proportion was 52.7%. The median intravenous furosemide dose in the first 24 hours was 160 mg in the urine sodiumguided group versus 80 mg in the urine volumeguided group (p<0.001). At 72 hours, the urine sodiumguided group showed greater congestion relief (median fluid overload score 4 vs. 6, p<0.001), lower body weight (median 83 vs. 88 kg, p=0.024), and less dyspnea (VAS 4 vs. 7; Likert 2 vs. 3; p<0.001 for both). Hospital stay was shorter by 2 days in the sodiumguided group (9±1.6 vs. 11±2.6 days, p<0.001), and persistent congestion at discharge was less frequent (7.3% vs. 20%, p<0.001). The composite of allcause death or HF rehospitalization at 3 months was lower in the urine sodiumguided group (21.8% vs. 36.4%, p=0.02). No significant betweengroup differences were observed in inhospital complication rates.Conclusion. In patients hospitalised with decompensated HF, furosemide dose titration during the first 24 hours based on urinary sodium concentration (compared to the urine volumebased approach) was associated with the use of higher doses, leading to greater weight loss, better congestion relief, an