Hypernatremia, defined as a serum sodium concentration greater than 145 mEq/L, represents a hyperosmolar condition where there is a deficit of free water relative to sodium. This electrolyte imbalance is critical in the ICU due to its association with high morbidity and mortality, particularly in vulnerable populations such as the elderly and those with impaired thirst mechanisms or altered mental status. The clinical management of hypernatremia requires a nuanced understanding of its etiology, the patient’s volume status, and the timing of the onset [1, 2] [Ref: Algorithm 23.1].