Principle of intravenous fluid therapy in the neurocritically ill patients

Intravenous fluid therapy is a fundamental treatment in intensive care units (ICUs). Although most clinical trials have focused on patients requiring active resuscitation of the intravascular volume, such as those experiencing shock or sepsis, neurocritically ill patients may also benefit from intravenous fluid therapy during crises involving elevated intracranial pressure or reduced cerebral perfusion pressure. This review provides a comprehensive history of the evolution of intravenous fluid therapy, highlighting the development of crystalloids and the challenges associated with colloids. Previously favored for their theoretical advantages in sustaining intravascular volume, colloids have recently come under scrutiny due to safety concerns, including adverse renal outcomes. In contrast, crystalloids, particularly balanced crystalloids, are now preferred. Balanced crystalloids improve acid-base status and pose a lower risk of hyperchloremic metabolic acidosis than 0.9% saline. This review summarizes the key findings of recent clinical trials comparing the efficacy and safety profiles of crystalloids and colloids in ICU settings with a specific focus on neurocritical care populations.