Currently, continuous renal replacement therapy (CRRT) is the main modality for renal support in critically ill patients with hemodynamic instability. Most studies have investigated the timing of RRT initiation. However, prolonged CRRT demonstrated the association of many unexpected events, such as catheter-related complications, catheter-related blood stream infection, hypotension, hypothermia, tachycardia, and atrial fibrillation. Up to now, there is a lack of evidence regarding the timing of withholding CRRT. The furosemide stress test (FST) is a tool that is easy to use and has more availability. The investigators aimed to apply FST to evaluate renal recovery compared with standard treatment in critically ill patients undergoing CRRT.