A 62-yrs-old male presents to you with an acute onset of hemiparesis. CT scan reveals an increase in intracranial fluid. Which solution will be most effective in reducing intracranial pressure following a large hemispheric stroke?: (A) 150 mmol sodium chloride, (B) 250 mmol glycerol, (C) 250 mmol glucose, (D) 350 mmol mannitol
Answer is D. Rapid removal of fluid from the brain can be produced by the administration of a fluid that increases the osmotic pressure difference between the brain and the cerebral vessels. The appropriate solution must have a higher osmolarity (that is, greater than 300 mM) and be composed of a solute that is impermeable to the blood- brain barrier Of the solutions listed, only urea and mannitol are hyperosmotic and of these, only mannitol is impermeable to the blood-brain barrier.