Mannitol and other diuretics in severe neurotrauma

Mannitol has replaced other diuretics as the agent of first choice for control of raised intracranial pressure (ICP) after brain injury. Mannitol should be given as a bolus intravenous infusion, over 10 to 30 mins, in doses ranging from 0.25 to 1.0 g/kg body weight. It may be given when high ICP is suspected, prior to computed tomography scanning, e.g., in patients who develop a fixed, dilated pupil or neurologic deterioration. This agent may also be used pre- or intraoperatively in patients with intracranial hematomas, and when high ICP is demonstrated in the ICU. It is more effective and safer when administered in bolus doses than as a continuous infusion. Mannitol may be safely used during the early resuscitation phase in hypovolemic patients with concomitant head injury, provided that plasma expanders and/or crystalloid solutions are given to correct the hypovolemia simultaneously. A Foley catheter should always be inserted when mannitol is used. Serum osmolality should be measured frequently after mannitol and maintained < 320 mOsm to avoid renal failure. Its beneficial effects and the rationale for its use are also reviewed.