くも膜下出血患者の脳血流へのdopamine少量投与の効果

THE EFFECT OF Low DOSE DOPAMINE ON CBF IN PATIENTS WITH SUBARACHNOID HEMORRHAGE

　抄録　Dopamine少量投与には脳血流量を増加する働きがある。くも膜下出血を来たした10症例に対し，dopamine 5μg／kg／min投与し，脳血流量の変化は，¹³³Xe吸入式局所脳血流測定装置にて測定した。投与直後においてはPaCO₂に変化なく，血圧は有意ではあったものの5.1％程度の増加で，両側平均脳血流量は10.3％増加し，病巣側8.7％，非病巣側16.6％といずれも有意に増加し，両側半球，病巣側，非病巣側脳血管抵抗は，ともに低下するものの有意な変化ではなかった。脳内盗血症候群は認められなかった。継続投与においても脳血流量は増加した。脳血管攣縮との関係では最も重症の血管攣縮はなかったが，脳血管抵抗において，病巣側における脳血流量の増加は比較的少なく，局所の血流低下を来たすperipheraltypeのspasmの場合にはその傾向がより強く認められた。以上より少量のDA受容体はα刺激作用を示さず，軽度のβ刺激作用を呈する可能性があるが主にDA受容体への作用による脳血流の改善の可能性が示唆された。

Cerebral blood flow was measured in 10 patients with subarachnoid hemorrhage using the ¹³³Xe inhalation methods. Regional cerebral blood flow (r-CBF) values were calculated with initial slope index, their values were compared with the blood flow response to the administration of low dose dopamine (DA).

CBF values of just after and continuous admini-stration of DA were compared with control va-lues. The measurement of r-CBF was performed immediately after the infusion of 5μg/kg/min DA for 30min. The focal ischemic lesions decreased, bi-hemispheric mean CBF value (7 cases without A-Com patients) increased by 10.3% significantly (paired T test), affected hemispheric mean CBF value increased by 8.7% significantly and non--affected hemispheric mean CBF value increased by 16.6% significantly. The PaCO₂ value didn't change but the mean systemic blood pressure increased by 5.1% significantly. The CBF values of continuous administration of DA for 10 days to 2 weeks were measured. The CBF values in-creased during the administration of DA.

The mean CBF values increased without the steal phenomenon and the mean arterial blood pressure increased slightly after the administration of DA. These phenomena were observed more significantly in non affected side than affected side. We suggest that the administration of DA increase the CBF values in patients with sub-arachnoid hemorrhage due to the stimulation of DA receptor.