Effect of dexamethasone on experimental brain edema in cats.

The authors studied the effects of dexamethasone, 0.3 mg/kg/hr administered intravenously beginning 1 hour before injury, in adult cats with brain edema secondary to cold-induced cortical lesions. Edema was quantitatively measured in cortex, gyral white matter, and central (deep) white matter at 3, 24, 48, and 72 hours, with and without dexamethasone, by determining specific gravity (density) of samples in a continuous gradient column. Cold-induced lesions resulted in edema, which was greatest in the white matter of the injured hemisphere but also present in the contralateral hemisphere. Except for a slight but significant increase in density (decreased edema) of cortex at 24 hours, dexamethasone therapy resulted in no reduction of cold-induced edema, and in some cases increased the edema.