Restricted fluid intake. Rational management of the neurosurgical patient.

Water balance studies in postcraniotomy patients indicate that restriction of fluid intake to 1 liter daily maintains the patient in homeostatic balance. A larger fluid intake will expand the extracellular space and presumably unfavorably influence cerebral edema. Daily observation of serum sodium and osmolarity and blood urea nitrogen, and preserving their normalcy, is a rational way of regulating fluid intake of the brain-injured patient. Fluid restriction should be used with caution if hyperosmolar agents, diuretics, or dexamethasone are also administered.