The treatment of raised intracranial pressure following aneurysm surgery.

The effect of intravenous mannitol infusion and withdrawal of cerebrospinal fluid on the intracranial pressure and clinical state was studied in 26 patients with raised intracranial pressure after direct surgery for ruptured aneurysm. Each method decreased the mean intracranial pressure by about 60% of the pre-treatment level. The maximal decrease following mannitol occurred after 60-90 minutes and generally lasted between three and four hours. The effects of mannitol did not decrease when repeated infusions were necessary. Rebound increases in the intracranial pressure following infusion were not observed. Withdrawal of cerebrospinal fluid lowered the intracranial pressure immediately and the effect persisted for approximately 60 minutes. This could be repeated as often as necessary and was without systemic disturbance, although a patent intraventricular catheter was necessary. The two methods could be used simultaneously.