[Fluid overload in critically ill patients. Hemodynamic effect vs hydrosaline balance]

The administration of high volumes of fluids during resuscitation of critically ill patients follows the recommendations of experts' committees that postulate volume expansion to correct deficits that may be associated with certain conditions (sepsis, trauma, surgery, etc), not primarily characterized by hypovolemia. These recommendations suggest that optimizing cardiac output may avoid occult deficit in tissue oxygen delivery and consumption that could lead to multisystem organic failure and death. The lack of benefit in the morbidity and mortality rates of patients with treatments directed to reach supranormal values of oxygen delivery, attempts against this hypothesis, since it fails to correct the primary hemodynamic dysfunction (arterial vasodilatación) and generates fluid overload. The probable mechanisms linked with the avidity to retain water and sodium by critically ill patients are reviewed and the use of restricted protocols that preserve fluid balance is encouraged to potentially improve outcome.