破裂脳動脈りゅう早期手術における術中低体温が術後脳血流に及ぼす影響

Abstract

Intraoperative mild hypothermia has been used during cerebral aneurysm surgery to reduce ischemic injury induced by temporary vessel occlusion and brain retraction. This study investigated the effect of intraoperative mild hypothermia on cerebral blood flow (CBF) after surgery for aneurysmal subarachnoid hemorrhage (SAH). Twenty-four patients with ruptured internal carotid or middle cerebral artery aneurysms in preoperative Hunt & Hess grade II or III underwent aneurysm clipping within 72 hours after SAH. During surgery, patients were randomly assigned to either intraoperative mild hypothermia (33°C, n=12) or normothermia (37°C, n=12). Brain SPECT with 99mTc-HMPAO or with 99mTc-ECD was performed on day-4, -7, and -14 after SAH. Regional CBF was determined in the basal ganglia, cingulate, frontal, and frontoparietal cortices using a semi-quantitative method. CBF in the frontal cortex ipsilateral to the aneurysm was significantly higher in the hypothermia than the normothermia group on day-4 (p<0.01), but not day-7 or-14. There was a similar trend in the the ipsilateral frontoparietal cortex, but not significant. There was no difference in regional CBF in the ipsilateral cingulate cortex and basal ganglia, and all contrateral regions during the study period. Intraoperative mild hypothermia may reduce the severity of ischemia induced by intraoperative temporary vessel occlusion and brain retraction, thus ameliorating postoperative CBF impairment.