[Changes in red blood cell aggregation rate after aneurysmal subarachnoid hemorrhage].

Red blood cell (RBC) aggregability is one of the important factors determining blood viscosity in the microcirculation. The RBC aggregation rate was monitored in 38 patients who underwent early aneurysmal clipping surgery after subarachnoid hemorrhage (SAH). The intravascular factors (hematocrit, serum albumin, alpha 2-macroglobulin, fibrinogen, IgG) that influence RBC aggregation were also examined. The RBC aggregation rate increased on days 5-7 but decreased significantly as a result of hypervolemic hemodilution therapy (H-H therapy). The hematocrit level was also reduced by H-H therapy. The serum albumin concentration decreased and the serum alpha 2-macroglobulin concentration increased significantly on days 5-7. After H-H therapy, the serum albumin concentration increased and the serum alpha 2-macroglobulin concentration decreased significantly. Serum IgG and plasma fibrinogen concentrations did not change significantly. It is known that albumin decreases and alpha 2-macroglobulin increases RBC aggregability. It has become apparent that serum albumin and alpha 2-macroglobulin play important roles in the determination of RBC aggregability after SAH. We conclude that the improvement in RBC aggregability induced by H-H therapy is effective for reversing progressive neurological deterioration due to cerebral vasospasm.