Fluid Balance Guided by Modified Venous Excess Ultrasonography Versus Standard Care in Patients With Acute Kidney Injury Receiving Continuous Renal Replacement Therapy

Inclusion Criteria: * Adults (≥ 18 years of age) * Admitted to ICU * Acute kidney injury by KDIGO criteria * Initiated CRRT by at least one of the following indications for RRT initiation: * Serum potassium ≥ 6.0 mmol/L, or * pH ≤ 7.20 or serum bicarbonate ≤ 12 mmol/L, or * Evidence of severe respiratory failure, based on a PaO2/FiO2 ≤ 200 and clinical perception of volume overload, or * Persistent severe AKI (sCr remains \> 50% the value recorded at randomization) for \> 72 hours from randomization * Participants giving informed consent Exclusion Criteria: * Refuse to participate * Previous diagnosis of end-stage kidney disease (ESKD) currently on kidney replacement therapy * Kidney transplant recipient * Receive RRT before ICU admission within 90 days * Structural kidney diseases which will interfere with intrarenal doppler ultrasound e.g. renal artery stenosis, autosomal dominant polycystic kidney disease * Patients with previously known conditions that interfere with portal doppler assessment, namely liver cirrhosis, severe tricuspid regurgitation with structural heart disease or massive ascites. * Underlying disease process with a life expectancy less than 90 days * Pregnancy * Severe cardiac rhythm disturbances (tachyarrhythmia, supraventricular tachycardia) * Intra-cardiac shunts; Ventricle septal defect, patent foramen ovale, atrial septal defect * Aortic aneurysm * Intra-abdominal hypertension (intraabdominal pressure ≥20 mmHg) * Expected life expectancy \<48 hours * Receiving extracorporeal membrane oxygenation (ECMO)