急性頭蓋内圧亢進時の髄液酸塩基平衡に関する研究

The author devised on pparatus for continuous monitoring of acid base balance of CSF without any CSF exposure to the atomosphere. The apparatus is an extracorporeal "ventriculo-cisternal circulation system" which is consisted of pressure pump, glass capillary electrode, Clark PO(2) eleotrode and Severinghaus Pco(2) electrode, all-lined up on a stainless steal conduit betweeen　lateral ventricle and cisterna magna. In the experimental cases of 5 dogs, the ventriculo-cisternal circulation system was used for monitoring acid base balanec of the CSF under acute intracranial hypertension produced by extradural balloon inflation. The blood Pco(2) was constantly watched during experiment to be kept in the normal range by means of a respirator. Pco(2) in the CSF began to increase in early stage above the pressure of CSF of 300 mmH(2)O and incseased more and more in parallel with raised pressure. HCO(3)- in the CSF was decreased when acute and more severe intracranial hypertension was maintained for hours. Hypercapnic acidosis and　metabolic acidosis occured in the CSF specifically when the intracranial pressure was raised acutely. Clinically, acid base balance of the CSF was studied on acute intracranial hypertension of three patients who suffered from brain tumor. Intracranial pressure was monitored continuously by pressure gauge transducer connected to the ventricular drainage. In this clinical research, CSF, arterial blood and jugular blood were sampled for measurement. Pco(2) in the CSF was increased　when the intracranial pressure was elevated above 500mmH(2)O and metabolic　acidosis was added when the pressure was more elevated continued. That is to say, CSF　became acidosis as same as experimental results. On the contrary, arterial　blood became respiratory alkalosis when the intracranial pressure was elevated　to 500-1000mmH(2)O. This phenomenon suggest that increse of hydrogenic ions induced by intracranial hypertension stimulates respiratory center. Hypercapnic acidosis and metabolic acidosis occur specifically in　the CSF independently from the change in the blood when the intracranial　pressure rises. Namely, the acid base balance of the CSF can not evaluated　from that of the blood. The author adovocates this state is hidden acidosis.