ステロイドの頭蓋内圧および頭蓋内コンプライアンスへの影響—特に水頭症における検討

EFFECT OF STEROIDS ON INTRACRANIAL PRESSURE AND PRESSURE-VOLUME INDEX IN PATIENTS WITH HYDROCEPHALUS

　抄録　年齢9歳から70歳までの水頭症患者13例に対してステロイド（betamethasone）を投与し，頭蓋内圧および頭蓋内コンプライアンスがどのように変化するかを検討した。ステロイドの投与方法および研究目的の違いにより2群に分けた。1群は5例に対して24時間連続的に頭蓋内圧測定を行い，その後ステロイドを初回量8mg静注した後6時間毎に4mgを筋注して更に24時間頭蓋内圧を測定した。他群は8例に対してまずMarmarouらの方法にもとづきpressure-volume index （PVI）を求め，次いでステロイド0.5mg／kgを静注し，45分後に再びPVIを求めて両者を比較した。その結果，頭蓋内圧そのものに対するステロイドの影響では，基本圧およびその振幅にはほとんど変化がみられなかったが，最大頭蓋内圧は5例全例が低下を示し，また最大振幅も明らかに低下した。またB波の出現頻度および最大連続出現時間も減少した。頭蓋内コンプライアンスへの影響ではPVIはステロイド投与後8例中7例に増加がみられた（p＜0.05）。以上の結果よりステロイドは頭蓋内コンプライアンスを増加させ，頭蓋内圧の上昇を抑制するものと思われた。

It is well-established that steroids (glucocorti-coids) have a beneficial clinical effects on patients with increased intracranial pressure, but there is still a controversy on the mode of action of steroids.

The purpose of this study is to investigate the effects of steroids on continuous intracranial pres-sure and on intracranial compliance using pressure-volume index (PVI).

Thirteen hydrocephalic patients, ranging from 9 to 70 years olds, without intracranial mass lesion nor brain edema were studied. The patients were divided into two groups. Group I : Five patients were monitored the continuous intracranial pres-sure for 24 hours again following the administra-tion of steroids in order to investigate the effects of steroids on continuous intracranial pressure. The method of the administration of steroids was that betamethasone 8 mg for initial dose was ad-ministerd intravenously and followed by 4 mg intramuscularly every 6 hours. There was little change in the baseline pressure and the amplitude on continuous intracranial pressure monitoring before and after the administration of steroids. But the maximum pressure and the maximum am-plitude significantly decreased after the administra-tion of steroids. The % time B-wave and the maximum continuous time of B-wave also decreased significantly. Group II : Eight patients were stu-died in order to investigate the effects of steroids on the intracranial compliance. PVI was measured according to Marmarou's method before and after the intravenous administration of steroids (beta-methasone 0.5 mg/kg). PVI increased in 7 out of 8 cases after the administration of steroids, which was statistically significant.

It can be concluded that steroids increase the intracranial compliance and inhibit the rise of in-tracranial pressure.