脳循環代謝モニターシステムの開発—II．内頸静脈血酸素分圧と脳循環代謝

MONITORING SYSTEM OF CEREBRAL BLOOD FLOW AND CEREBRAL METABOLISM : PART II. RELATIONSHIP BETWEEN INTERNAL JUGULAR O2 TENTION AND CEREBRAL BLOOD FLOW

　抄録　本研究の目的は，内頸静脈血酸素分圧PjO₂測定による脳循環モニターの可能性についての検討である。

　PjO₂値は内頸静脈球部より採血しABL−2（Radiometer）にて測定した。対象は各種脳血管障害入院患者である。

Changes of PjO₂ values of internal jugular vein were monitored in patients with various types of cerebrovascular disease.

The significance of PjO₂ monitoring was evalu-ated.

1) Control value of PjO₂ in thirteen normal control cases was 36.7±1.9mmHg (mean±SD).

2) Limit of brain hypoxia showing no neurologi-cal sign and symptom in patients with occlusive cerebrovascular disease was studied by the stepwise reduction of arterial blood pressure, using drip in-fusion of trymetaphan camsylate, under the careful monitoring of signs and symptoms and monitoring of PjO₂ and EEG. Appearance of signs and sym-ptoms of brain hypoxia were checked by yawning and EEG slowing. At the time of the appearance of brain hypoxia PA was 28.6±3.2mmHg.

3) CO2 reactivity of CBF was studied in patients with occlusive cerebrovascular disease. Relation between PaCO₂ and PjO₂ was as follows;

PjO₂=0.68･PaCO₂+7.55

4) Within 24 hours after the onset of stroke, ipsilateral PjO₂ of the cases with disturbance of consciousness was lower than that of the cases without disturbance of consciousness, which might indicate the significant decrease of CBF in the former cases. During 3rd to 7th day after the onset the cases with disturbance of consciousness showed the significant elevation of PjO₂, which might indicate the reduction of cerebral metabolism.

5) The elevation of ipsilateral PjO₂ were well correlated to the degree of hemispheric brain swelling.

6) During general convulsion, high level of PjO₂ values were observed.

7) PjO₂ values were inversely correlated to the hemoglobin values after blood transfusion, which was mainly due to the decrease of CBF by high content of hemoglobin.