くも膜下出血後神経症状を呈した症例に対するhydrogenated ergot alkaloidの効果について—脳循環・脳代謝からの検討

EFFECT OF HYDROGENATED ERGOT ALKALOIDS ON CEREBRAL METABOLISM OF THE PATIENTS WITH NEUROLOGICAL DEFICITS AFTER SUBARACHNOID HEMORRHAGE

はじめに

　Hydrogenated ergot alkaloids （HEA）は脳細胞の酵素活性を正常化して細胞の代謝機能を改善する作用と，交感神経のα受容器遮断作用を有する薬剤である。実験的に各種動物においてHEAの投与により脳血流量，脳代謝量が改善されたとする報告^2,16,17）が多い。臨床的には脳血管障害あるいは頭部外傷後遺症などに投与され，主にα受容器遮断作用が認められたが^4〜7,12）脳血流量あるいは脳代謝が改善されたという報告^6,7）は少ない。投与法・投与量が一定でないため結果が異なるものと思われ，投与量が少ない場合脳血流量は増加しないとする報告^6）もある。

　われわれは対象とする病態をくも膜下出血後1週以降の神経症状を呈した症例に限定し，HEAを1.5mg経静脈的に投与し，前後の脳血流量，脳代謝量の変化を検討した。さらにその後1週間投与し髄液代謝，および脳波所見の変化を検討した。

Cerebral blood flow and metabolism were meas-ured in 9 patients with neurological deficits after subarachnoid hemorrhage using the ¹³³Xe intra ca-rotid injection methods. Regional cerebral blood flow (r-CBF) values were calculated with initial slope method (2 minutes flow index), their values were compared with the blood flow response to ar-terial PCO₂ and to administration of hydrogenated ergot alkaloids (HEA). In case of repeated exami-nation nfter short interval CBF values were cor-rected useing the rate of reproducibility. The content of oxygen, glucose, lactate and pyruvate in the arterial and the internal jugular blood were measured, and CMRO₂, CMR glucose, CMR lactatevalues were calculated.

1st step: The measurement of r-CBF was per-formed immediately after the infusion of 1.5mg HEA for 15 minutes. The focal ischemic lesions decreased, mean CBF value increased by 8% signi-ficantly, arterio-venous difference of oxygen value increased by 20% significantly and CMRO₂ value increased by 26% significanly after HEA adminis-tration.

2nd step: 1.8mg HEA was infused for one week. EEG findings were improved after administration of HEA. The pressure and the lactate levels of cerebrospinal fluid decreased, but the effect of HEA must be carefully distinguished from natural recov-ery.

Administration of HEA increased the CMRO₂ values and consequently increased the mean CBF values.