The limits of cerebral dehydration in the treatment of head injury

Eighteen patients with fatal head injury were matched with survivors for age, sex, and nature and severity of injury. All were treated with cerebral dehydration. Only four patients survived whose peak serum osmolality exceeded 340 mosm/kg; none survived above 378 mosm/kg. Only four patients survived whose peak serum sodium concentration exceeded 155 mEq/L; none survived above 166 mEq/L. Serum osmolality should probably not be allowed to rise above 340 mosm/kg, and serum sodium concentration should not be allowed to exceed 155 mEq/L. Aggressive dehydration, i.e., osmotherapy, is best accomplished with intracranial pressure monitoring.