Natriuresis-guided Depletion After Cardiac Surgery

All patients were equipped with urinary catheters, allowing for continuous urine collection. Urine output was measured every 2 hours, and the recorded volumes were entered into a monitoring software to ensure accurate follow-up

All patients were equipped with urinary catheters, allowing for continuous urine collection. Urine output was measured every 2 hours, and the recorded volumes were entered into a monitoring software to ensure accurate follow-up.

Total natriuresis is measured at 24 hours using the indirect potentiometry technique at the CHU Amiens-Picardie laboratory.

Total natriuresis is measured at 48 hours using the indirect potentiometry technique at the CHU Amiens-Picardie laboratory.

The VExUS score is an echocardiographic score (ranging from 0 to 3) used to assess venous congestion at the cardiac, renal, and hepatic levels. This score will be measured after randomization and at 48 hours after randomization.

Grade 0: IVC <2cm = No Congestion Grade 1: IVC >2cm with any combo of Normal or Mildly Abnormal Patterns = Mild Congestion Grade 2: IVC >2cm and one severely Abnormal Pattern = Moderate Congestion Grade 3: IVC >2cm and >2 Severely Abnormal Patterns = Severe Congestion

Total dose of loop diuretics administered during the study period (mg)

Fluid balance corresponds to the difference between administered fluids (intravenous infusions, blood products, enteral nutrition) and fluid losses (urine output, blood loss, digestive losses, drain output). It is calculated using the DianeRéa software (Bowmedical, version 4.8.11.22887), taking into account all fluid inputs (administered fluids, medications, nutrition) and all fluid outputs (urine, drains, perspiration) over the period from inclusion to 48 hours after randomization

Composite outcome measuring the number of participants who experience at least one of the following postoperative complications within 30 days of surgery:

Cardiovascular:

• Acute left and right ventricular systolic heart failure
• Acute circulatory failure requiring catecholamine support
• Supraventricular (e.g., atrial fibrillation) or ventricular arrhythmias.

Respiratory:

• Acute respiratory distress syndrome (ARDS)
• Prolonged orotracheal intubation (> 24 hours).
• Reintubation.

Renal:

• Acute kidney injury (AKI), defined by a postoperative increase in serum creatinine of at least 50% and/or ≥ 26.5 µmol/L from baseline, and/or urine output < 0.5 mL/kg/h for ≥ 6 hours (KDIGO criteria). Serum creatinine and estimated glomerular filtration rate (eGFR) measured on the day of hospital discharge.

Gastrointestinal:

• Mesenteric ischemia or ischemic colitis, documented by imaging (CT scan), colonoscopy, and/or surgery.
• Length of hospital stay (days).
• In-hospital mortality.

Number of participants presenting contraindications prior to furosemide administration, including:

• Symptomatic hypotension
• Hypokalemia
• Impaired renal function

Number of participants for whom corrective actions (e.g., potassium supplementation, fluid resuscitation) were implemented to allow safe administration of furosemide.