NORMOGLYCEMIA (NOT HYPOGLYCEMIA) OPTIMIZES OUTCOME FROM MIDDLE CEREBRAL-ARTERY OCCLUSION

We examined the effects of serum glucose concentration during middle c erebral artery (MCA) occlusion in the cat on death rates in animals th at died from hemispheric edema and on infarct size in animals that sur vived. We occluded the MCA permanently in some groups and released the clip after 8 h in others. By injecting or infusing glucose solutions, saline, or insulin, we maintained six animal groups steadily either h yper-, normo-, or slightly hypoglycemic before and for 6 or 8 h after permanent or 8-h temporary MCA occlusion. Studies with these groups re vealed a distinct optimal outcome with normoglycemic animals. In three additional groups, we altered the glycemia after permanent occlusion from hyper- to normo- or hypoglycemia and from normo- to hyperglycemia . Two of the three hypoglycemic groups (8-h reversible and permanent h yper- to hypoglycemic occlusions) yielded the worst outcomes in this s tudy, with >10x larger median infarcts than the best outcome group (no rmoglycemic permanent occlusion). Hyperglycemia also was detrimental a nd increased infarct size and mortality after permanent occlusion. Res toring the cerebral blood flow after 8 h of occlusion increased the de ath rate from hemispheric edema compared with a maintained occlusion. Following permanent MCA occlusion, converting from normo- to hyperglyc emia or vice versa yielded outcomes intermediate between a sustained n ormo- or hyperglycemia. A regression analysis of the normo- and hyperg lycemic groups and the two groups with glycemia altered after permanen t occlusion showed a significant linear correlation between glycemia l evel at and 1 h after MCA occlusion and median infarct size.