<I>Red Blood Cells are Essential for Late Vasospasm Following Experimentally Induced Subarachnoid Hemorrhage in Dogs</I>

Abstract

The in vivo spasmogenic activity of various blood components was examined in dogs. Each blood fraction was injected into the cisterna magna at 0.5 or 1.0 ml/kg body weight, after the removal of 0.5 ml/kg body weight of cerebrospinal fluid, and vertebral angiography was then performed. Whole blood induced both early and late arterial spasm. Platelet-rich and platelet-poor plasma produced only early spasm, and no arterial narrowing was observed on days 1, 3, and 7 after injection. On the contrary, intracisternal injection of washed red blood cells (0.5 ml/kg body weight) produced no arterial narrowing for 6 hours after injection and induced moderate arterial narrowing on days 1, 3, and 7 after injection. Hemolysate (a 10-gm/dl concentration of hemoglobin) produced prolonged monophasic arterial narrowing after injection. These results imply that red blood cells are required for late, prolonged arterial narrowing after experimental subarachnoid hemorrhage.