Hemodilution with low-molecular-weight hydroxyethyl starch after experimental focal cerebral ischemia in rabbits

Newly developed colloid volume-expanding agents with mean molecular weights lower than currently available agents may improve outcome after stroke with fewer allergic and coagulation system side effects. The smaller molecule, however, may exacerbate ischemic cerebral edema if it accumulates in areas where ischemia has damaged the blood-brain barrier. We administered low-molecular-weight hydroxyethyl starch to rabbits after embolic infarction and measured specific gravity and total water content. We found evidence of ischemic edema in the hemisphere ipsilateral to the embolic arterial occlusion, but the measures of edema were not different in treated and control groups. Of those rabbits suffering severe neurologic deficit, mortality was 2 of 13 in the treated compared with 7 of 12 in the control groups (p less than 0.01). Thus, hemodilution with low-molecular-weight hydroxyethyl starch did not exacerbate cerebral edema and may have improved survival in this model.