Comparison of preventive effect of high thoracic epidural block on cerebral vasospasm with that of nimodipine in the rabbits

Objective To compare the preventive effects of high thoracic epidural block (HTEB) on cerebral vasospasm (CVS) following subarachnoid hemorrhage (SAH) with that of nimodipine in rabbits. Methods HTEB at T6~7 epidural space was performed in 60 rabbits, who were randomly divided into 4 groups of 15 rabbits each, i. e. the sham-operation group, control group, HTEB treatment group, nimodipine treatment group. SAH was developed by two injection of autoblood into the cistern magna (0.5 ml/kg). Transcranial Doppler ultrasonography was used to detect the basilar artery mean flow velocity (Vm) 1, 7 and 14 days after SAH. The changes in histological morphology of the basilar artery were observed under a light Microscope. Results The Vm of the basilar artery in the control group and two treatment groups was significantly faster than that in the sham operation group (P0.01); The Vm of the basilar artery in the control group was significantly faster than that in both the treatment groups (P0.05); There were insignificant difference in the Vm of the basilar artery between both the treatment groups (P0.05). Pathological observations showed that in the control group the lumina of the basilar arteries was narrower and the basilar artery walls were thicker than those in the two treatment groups, but there were no significant difference in the walls thickness and the lumens sizs of the basilar arteries between the two treatment groups. Conclusion Continuous HTEB is similar to nimodipine in preventive effect on SAH-associated CVS in rabbits.