Methodology for the control of intracranial pressure with hypertonic mannitol

The response to intravenous bolus administrations and continuous infusions of hypertonic mannitol to control elevated (greater than 25 torr) intracranial pressure (ICP) is presented. Sixty patients received 120 bolus infusions of mannitol (0.18-2.5 g/kg/dose) with a prompt peak reduction at 44 minutes (range 18 to 120 minutes). There was no relationship between dosage and rapidity of peak response. All administrations of 1.0g/kg/dose, or higher, consistently reduced ICP 10% or more from control values, but dosages below 1 gm/kg/dose did not always reduce ICP. Return to control ICP following mannitol was unpredictable, and was related to the initial ICP and the volume of fluid replacement. A continuous infusion of mannitol was administered to maintain ICP below 25 torr in 18 patients. This infusion ranged from 6 to 100 hours (X 28.8+/-28.9 hours) and required a total dosage of 2-20 mg/kg, and was successful in 16 of the 18 patients. Emphasis is placed on close observation of the patient's serum osmolality and electrolytes during therapy, as well as quality and magnitude of replacement. No set rules are given for control of ICP, but a guideline is made to meet the individual patient's requirements.