Enhanced erythrocyte aggregability in neurosurgical interventions carried out with mannitol administration

Blood rheological properties were examined in patients before, during and after neurosurgical operations of arterial aneurisms, as well as in patients where no operation was carried out, and in healthy volunteers. Erythrocyte aggregability was quantified by using the "Georgian technique" and compared with other indices of blood rheological disorders. Prior to the operations the erythrocyte aggregability did not differ significantly in both healthy probands and neurosurgical patients. In the course of surgery the index increased gradually and became almost two times higher than before operation in the same patients. Evidence was obtained that this effect was accounted for the mannitol administration, since in the control cases, without operations, its infusion into the circulation produced a comparable increase of the aggregability. Other indices of hemorheological disorders did manifest no regular and significant changes in the same patients. The enhanced erythrocyte aggregability might be a factor disturbing to a degree the blood rheological properties in cerebral microvessels of neurosurgical patients operated with mannitol.