Delayed cerebral ischemia is the major cause of death and disability in patients suffering from an aneurysmal subarachnoid hemorrhage (SAH). A method of reducing the risk of ischemic deficits during surgery is based on the improvement of brain microcirculation by means of hemodilution. This study presents 80 patients who underwent surgery due to SAH for ruptured intracranial aneurysms. Fifty were selected and underwent perioperative hemodilution. The other 30 comprised the control group. There were no statistically significant differences in the composition of these groups in regard to the commonly recognized prognostic factors. Moore's method was used to evaluate the circulating blood volume in patients operated on with normovolemic hemodilution. After the induction of anesthesia, 20% of the estimated volume of circulating blood was extracted and replaced by Dextran 70 000 and Ringer solution in equal parts. At the time of aneurysm clipping the hematocrit level was lowered to 0.30. In the control group it equaled 0.37. Blood was retransfused directly after aneurysm clipping or during the peri-operative bleeding. The results of treatment were evaluated at the end of the hospital stay as well as one and six months following discharge using the Glasgow Outcome Scale (GOS). Early results evaluated at the time of discharge were better in the group who were operated on using hemodilution than in the control group (GOS I-II 78% and 63.4% respectively). Surgical treatment of intracranial aneurysms using hemodilution, evaluated 6 months following discharge showed good results (GOS Grade I) in about 10% more of hemodiluted patients then in the control group. The difference was statistically significant. In addition, perioperative hemodilution reduced the need for blood transfusions.

Keywords: peri-operative hemodilution, intracranial aneurysm surgery