CReep and Maintenance flUid Sodium Chloride ADministration rEduction in cRitically Ill adultS

This study is enrolling adult patients who require a prolonged stay in the intensive care unit (ICU). These patients often receive large amounts of intravenous fluids, which can contain more salt (sodium and chloride) than the body normally needs. Extra salt and water can build up in the body and may delay recovery. The study will test two strategies: Fluid creep: These are fluids used to dilute medications or keep intravenous lines open. Usually, the choice is based on habit. In the intervention group, a salt-free glucose 5% solution will be used (if the responsible pharmacist confirms it is compatible with the medication). Maintenance fluids: These fluids cover daily needs for water and electrolytes. In the intervention group, a lower-salt solution (NaCl 0.3% in glucose 3.3%) will be given, with volume decided by the treating physician. The comparison group will receive usual care: NaCl 0.9% (commonly called "normal saline") for fluid creep, and an isotonic solution (PlasmaLyte) for maintenance fluids. The main outcome is the number of days patients are alive and free of life support (such as ventilator or dialysis) during the first 90 days. Other outcomes include abnormal sodium, chloride, or glucose levels, fluid balance and need for diuretics, kidney injury, use of dialysis, time on the ventilator, survival, and length of ICU and hospital stay. A smaller substudy (SALADIN) will measure in detail how the body handles sodium, chloride, and water using additional calculation on blood tests, urine collections, body weight, and bioimpedance analysis