Reduction of regional cerebral blood flow during brain retraction pressure in the rat

The use of brain retractors in intracranial operations may lead to focal cerebral ischemia and thereby cause brain infarction. To estimate the risk of ischemic damages, the authors investigated the regional cerebral blood flow (rCBF) in rats by means of autoradiography with 14C-iodoantipyrine at different brain retractor pressures (BRP). A reduction in rCBF to between 10 and 75 ml/100 gm/min with 20 mm Hg of BRP for 30 minutes was found in brain cortex lying under the retractor (normal 55 to 150 ml/100 gm/ min). With a BRP of 30 mm Hg for 30 minutes, rCBF was reduced to between 0 and 40 ml/100 gm/min, and with a BRP of 40 mm Hg for 15 minutes rCBF was 0 to 15 ml/100 gm/min. The rCBF in the basal ganglia remained unchanged. Even with a BRP of 20 mm Hg for 30 minutes, there seemed to be a risk of focal ischemic damage.