Rethinking Fluid Balance: The Shift Toward Deresuscitation in Critical Care

Intravenous fluid therapy is central to resuscitating critically ill patients, yet accumulating evidence shows that excessive fluid administration and positive fluid balance contribute directly to respiratory failure, acute kidney injury, prolonged mechanical ventilation, and mortality. Modern fluid stewardship reframes intravenous fluids as pharmacologic agents with dose-dependent toxicity and emphasizes the ROSE (Resuscitation, Optimization, Stabilization, and Evacuation) model. Observational studies consistently link fluid overload (often defined as fluid balance >5% baseline weight) to worse outcomes, and early or protocolized deresuscitation (removal of accumulated fluid once perfusion goals have been achieved) through diuretics or ultrafiltration can reliably achieve negative fluid balance and improve pulmonary parameters without increasing acute kidney injury. Randomized trials of restrictive strategies demonstrate improved ventilator-free days and shortened length of stay but no mortality benefit, underscoring the need for individualized, physiology-guided approaches. Evidence for active deresuscitation remains mixed. Diuretic-based protocols can lower mortality and reduce renal replacement therapy use in select populations, while ultrafiltration studies highlight the importance of avoiding both insufficient (<1 mL/kg/h) and excessive (>1.75 mL/hg/h) fluid removal rates. Knowledge gaps persist around optimal timing, patient selection, hemodynamic monitoring, and fluid removal targets. Ongoing trials aim to refine protocolized resuscitation and better define strategies to safely restore euvolemia, mitigate organ dysfunction, and improve outcomes in critical illness.