Treatment of acute focal ischemia with continuous CSF drainage and mannitol

A simple implanted device was used to occlude acutely the left middle cerebral artery (MCA) of 32 conscious cats. Groups of 18 cats each were treated with continuous cerebrospinal fluid (CSF) drainage, mannitol (1 gm/kg i.v.), or a combination of continuous CSF drainage and mannitol (1 gm/kg i.v.). Eight cats served as a control group. The neurological status of cats treated with mannitol improved transiently. Perfusion with a mixture of colloidal carbon and buffered paraformaldehyde was carried out 12 hours following MCA occlusion. Gross swelling of cerebral tissue, distribution of colloidal carbon, and breakdown of the blood-brain barrier to fluorescein were similar in the 4 groups. Reduction of mean capillary luminal diameter to 4.5 +/- 1.0 micron (control 6.5 +/- 1.0 micron) in the left Sylvian cortex was unaltered by treatment. A significant difference in the distribution of severe neuronal alterations was not demonstrated.