Intracranial and systemic effects of hetastarch in experimental cerebral edema

These experiments were done to determine the effectiveness of oncotic and oncotic/diuretic ( oncodiuretic ) therapy in dogs with experimental cerebral edema induced by a cold lesion. Dogs were divided into 3 groups and were treated for 6 h with either crystalloid (control group), a 12% hetastarch solution, or a 24% hetastarch solution plus furosemide. The cerebral effects of treatment were evaluated by intracranial pressure (ICP) measurements and by autopsy measurements of brain density and brain water content. The systemic effects were evaluated by measuring fluid balance, wedge pressure, hematocrit, free-water clearance, and serum vasopressin level. Hetastarch and hetastarch /furosemide significantly reduced ICP, increased brain density, and decreased water content of the edematous brain. Hetastarch alone caused a positive fluid balance and marked hemodilution but did not normalize vasopressin levels, whereas hetastarch /furosemide caused a marked diuresis without changing the hematocrits, and normalized vasopressin levels. Oncodiuretic therapy, in contrast to traditional fluid restriction, seems to decrease ICP effectively by causing normovolemic dehydration.