Clinical, hemodynamic, and hemorheological effects of isovolemic hemodilution in acute cerebral infarction.

The effect of isovolemic hemodilution on regional cerebral blood flow (rCBF) and neurological symptoms in 35 patients with acute ischemic stroke was evaluated. Twenty-one patients had internal carotid artery occlusion, and 14 had middle cerebral artery occlusion. Isovolemic hemodilution combined with venesection and the administration of fresh plasma to reduce the hematocrit (Hct) to 33% was performed within 72 hours of the onset of symptoms. The Hct decreased by 27% and was correlated directly with whole blood viscosity (WBV) at a shear rate of 10 sec-1 after the hemodilution. The cardiac output increased by 29% after hemodilution without significant alterations in cerebral perfusion pressure and showed a good inverse correlation with the Hct and the WBV. The rCBF of the area supplied by the ischemic middle cerebral artery (MCA) increased by 30% and was related inversely to the Hct and the WBV. The cerebrospinal fluid pressure increased by 16%, but no symptoms of raised intracranial pressure were observed. The N20 peak latency of the sensory evoked potential decreased by 5%, and the neurological score was improved by 12%. Isovolemic hemodilution thus resulted in an increase of the rCBF in the area supplied by the affected MCA, leading to significant neurological improvement.