A quasi experimental study that aims to verify whether the incorporation of VExUS in patients with AKI in the Intensive Care Unit (ICU) may prompt tailored interventions to increases the number of days free from Renal Replacement Therapy (RRT) during the first 28 days.

Fluid overload is associated with organ dysfunction, such as Acute Kidney Injury (AKI), and increased mortality. It remains unclear if fluid overload is merely an epiphenomenon in critically ill patients or if organ congestion is a mediator of complications. Considering AKI related to fluid overload, diuretic therapy would reduce venous congestion and improve renal blood flow. The Venous Excess Ultrasound score (VExUS) identifies clinically significant venous congestion and indicates a high risk of post-operative AKI. This quasi-experimental study aims to verify whether the incorporation of VExUS in patients with AKI in the Intensive Care Unit (ICU) may prompt tailored interventions to increases the number of days free from Renal Replacement Therapy (RRT) during the first 28 days.

Inclusion Criteria:

• Non-elective ICU admission
• Severe acute kidney injury (AKI) defined either: A ≥ 2-fold increase in serum creatinine from a known pre-morbid baseline or during the current hospitalization OR Urine output < 6.0 mL/kg over the preceding 12 hours

Exclusion Criteria:

• Life-threatening indication of RRT (defined as intractable hyperkalaemia, acidosis, uraemic symptoms) at Day 0
• RRT before recruitment
• Use of Extracorporeal membrane oxygenation (ECMO)
• Hepatic cirrhosis or other condition with portal hypertension
• Lack of commitment to provide RRT as part of limitation of ongoing life support
• Known pre-hospitalization advanced chronic kidney disease, defined by an estimated glomerular filtration rate < 30 mL/min/1.73 m2 or chronic RRT
• Refusal to sign the informed consent form