脳死症例における経時的脳血管撮影所見の解析

ANALYSIS OF ANGIOGRAPHICAL FINDINGS IN PATIENTS WITH SEVERE BRAIN DISORDERS PROGRESSING TO BRAIN DEATH

　抄録　脳死時期近辺の脳血管撮影所見をいかに評価すべきかを目的とした。最終的に脳死と診断された窒息2例を含むテント上病変72症例を対象とし，持続的頭蓋内圧（ICP）モニタリング下の様々な時点で行われた総頸動脈写（CAG）所見を検討した。ICPの上昇，脳灌流圧（CPP）の低下に従い頭蓋内fillingの減少が見られたが，ICPが平均血圧に達した以降はその関係はなくなる。CAG上"Non-filling"なら確実に臨床的脳死であり，脳死は脳循環停止に先行した。脳循環停止の証明のための血管撮影の施行時期は，臨床的に脳死と診断され，しかもCPPがzeroとなった以後が最良である。しかし，わずかながら認められるfilling像が脳循環の一部を示すか否かの解釈にはさらなる検討を要する。

In the present study, the authors analysed the serial angiographical findings progressing to brain death and their relation to the intracranial pres-sure (ICP) and the cerebral perfusion pressure (CPP). Seventy two patients, from four to eighty four years old (fourty six males and twenty six females) admitted in the Department of Emergency Medicine, University of Tokyo Hospital during the period from January, 1981 to April, 1986, were studied. Their underlying diseases were supratentorial primary brain lesions except two cases with asphyxias which progressed to brain death. ICP was continously measured and CPP was calculated as the pressure gradient between the mean arterial blood pressure (MAP) and ICP. The direct carotid angiography was performed to follow the cerebral circulation. Fourty five patients were subjected to barbiturate (pentobar-bital sodium) therapy.

The degree of the intracranial filling staged as "Non-filling", "Siphon-filling", "Partial-filling", "Delayed-filling", "All-filling" correlated signifi-cantly with ICP and CPP. These relationships, however, disappeared once ICP exceeded MAP. When "Non-filling" angiogram was obtained, clini-cal signs had already showed brain death. On the other hand, minimal flow ("Siphon-filling", "Partial-filling", "Delayed-filling") were still demonstrated in six brain death cases while ICP was approach-ing its "peak" value.

This study showed that clinical diagnosis of brain death preceeded the Non-filling phenomenon, suggesting that, for the demonstration of the cerebral circulatory arrest, the angiograms should be performed after the clinical diagnosis of brain death was established and CPP became zero. The evaluation of the extremely slow and minimal fil-ling is still a matter of discussion. This study sug-gested that these "minimal filling"s were irrever-sible phenomena in the process of circulatory arrest. However, the possibillity still remains that "minimal filling" might indicate the existance of cerebral circulation. Further investigation on its significance should be required.