A novel treatment for ischemic intracranial hypertension in cats. There is no accepted efficacious treatment for ischemic cerebral edema. We show in a cat model of focal cerebral ischemia that infarct volume can be reduced (p less than 0.05) by ventriculocisternal perfusion with an oxygenated fluorochemical emulsion (bis-perfluorobutylethylene). An accompanying effect of such ventriculocisternal perfusion is a reduction in intracranial pressure. At 18 hours following the start of the perfusion, there was a significant (p less than 0.05) difference in intracranial pressure between nonperfused controls (mean 11.4 [range 2.3-23.0] torr, n = 6) and cats perfused with an oxygenated nutrient solution not containing fluorochemical (mean 11.3 [range 3.0-29.0] torr, n = 8) or animals perfused with the oxygenated fluorochemical emulsion (mean 2.21 [range 0-3.5] torr, n = 7). Perfusion with this oxygenated fluorochemical emulsion warrants further study as a treatment for elevated intracranial pressure. 