The hydroelectrolytic balance is a critical point in the management of hospitalized patients: meeting hydroelectrolytic requirements plays a fundamental role in short- and long-term prognosis. In pathological situations, it is essential to consider the balance between body balance and the environment (intake and loss), as well as the internal balance between intracellular and extracellular compartments. There is no general protocol for IV fluid therapy for each clinical situation; fluid guidelines should be tailored to each case, using them only when necessary. If needed, it is important to estimate for how long and what type of intravenous solution to use, as well as the objective for its use: for maintenance or replacement of pathological losses, as a route for drug administration, for resuscitation, etc. It is crucial to adjust the intake, especially in situations of organ failure (heart failure, acute kidney failure, liver failure), and to perform daily fluid balance, adjusting according to intake and loss. The use of fluid therapy requires monitoring with both clinical and analytical signs.
The absence of hydration in the hospitalized patient when it is necessary is detrimental, causing decreased tissue perfusion, prerenal kidney failure, and coagulation disorders. However, fluid therapy also has risks, leading to iatrogenesis such as hyponatremia, overexpansion of the interstitial space, or hyperchloremic acidosis when using normal saline. In patients receiving fluid therapy, oral intake should be started as soon as possible, provided that the patient’s pathology and clinical situation allow it. In conclusion, both excess and deficiency of hydration have prognostic impacts on hospitalized patients. Prolonged fluid therapy can affect clinical outcomes in patients, having risks, so its need should be evaluated.