脳圧下降剤，特に高張尿素液に関する臨床的研究—前篇

CLINICAL STUDIES ON INTRACRANIAL PRESSURE LOWERING AGENTS WITH SPECIAL REFERENCE TO HYPERTONIC UREA SOLUTION:Part 1

I．緒言

　頭蓋内圧亢進症（脳圧亢進），ことに急性のものは患者の自覚的苦痛を増加させるだけでなく，全身状態の悪化をきたし，時としてはpressure coneによる死を招く。幸い死をまぬがれ得たとしても高度な脳圧亢進の持続した結果として種々の不つこうな後遺症を残すことが少なくない。臨床治療の立場から原因のいかんを問わず対症的に，たとえその効果が一過性であつても，確実に脳圧下降をはかれる薬剤の出現が望まれるわけである。

　1919年Weed and McKibben^41）42）が高張溶液は頭蓋内圧（脳圧もしくは髄液圧）の下降をきたすことを報告して以来，種々の高張溶液の脳圧下降剤が報告され，臨床的にも用いられてきたが，その多くは脳圧下降作用が不確実で効果の持続時間も短く，時には好ましからざる二次的圧上昇（rebound phenomenon），あるいは副作用のあることが指摘され，今日まで一般に臨床的に使用されているのは高張ブドウ糖液にすぎない。この高張ブドウ糖液にしても上述のような欠点があるために，その効果を疑問視して二次的圧上昇の危険を強調し，その乱用をいましめる人^13）16）さえあるのが最近までの状態であつた。

Our clinical studies on the effect of various kinds of intracranial pressure lowering agents esp. hyper-tonic urea solution and its influence to the human body are presented.

1. 30% urea solution in 5% dextrose resulted in average 76% lowering of initial intracranial pressure and the duration of its effect was 137 minutes. Both pressure lowering effect and its duration of 30% urea solution were far more potent than those of 50% dextrose. Its effect paralleled to the dosis and the infusion rate. The effect was much augmented when 10% dextrose was utilized as its solvent.

2. Of intracranial pressure lowering agents other than urea, 20% mannitol and aminophyllin aroused interest, because the former caused less rebound phenomenon and did not disturb renal functions and the latter is not hypertonic solution. 6% MT, Dia-mox and steroid hormones were also studied.

3. When aminophyllin was added to dextrose, 50% fructose and 30% urea solution to reinforce the effect of the agents, the pressure lowering effect was more marked than these agents were administered respectively without aminophyllin.

4. Comparing with the effects produced by other agents administered in the same patient, the grade of lowering of intracranial pressure by urea was much more prominent.

5. Urea administration resulted in increase in blood and c.s.f. urea level, urea and electrolytes in urine and urinary output respectively, and also slight elevation of blood pressure, but almost no change was observed in serum electolytes, bleeding time, coagula-tion mechanism, E.C.G., liver and renal functions. The level of blood urea returned to normal within 24 hours.

Clinical application of hypertonic urea solution will be discussed in the second report.