Because of mannitol's osmotic properties, it promotes the movement of fluid from the intracellular into the extracellular space. In emergency care, mannitol is used in the treatment of closed head injury to decrease cerebral edema and intracranial pressure, and in the promotion of urinary excretion of toxic substances. Category C Hyperventilation should be supplemented with mannitol. In-line filter should always be used.
Effectiveness depends on large doses and an intact blood-brain barrier.
The use of mannitol and its dosages in emergency care are controversial.