The comparison was undertaken to examine 31 patients with various brain neurosurgical abnormalities to evaluate the efficiency of some of the most widely used preventive measures for retraction ischemia, which are aimed at reducing the brain volume at surgery: preoperative administration of a saluretic, osmodiuretic solution, hyperventilation, tumor cyst puncture, lumbar and ventricular drainage. The findings suggest the efficacy of such approaches, as tumor cyst puncture, intravenous administration of an osmodiuretic, ventricular and, possibly, lumbar drainage. Such methods as preadministration of saluretic hyperventilation are ineffective.