ACUTE INCREASED INTRACRANIAL PRESSURE (ICP) AND HYPERBARIC OXYGENATION (OHP):WITH SPECIAL REFERENCE TO THE EFFECT OF OHP ON CEREBROVASCULAR TONE Seigo Nagao 1 , Kiyoshi Iwatsuki 1 , Taketoshi Manabe 1 , Shyojiro Okao 1 , Tatsuro Akioka 1 , Akira Nishimoto 1 , Shizumi Kayata 2 , Noriyuki Tabuchi 2 1Department of Neurological Surgery, Okayama University Medical School 2Kagawa Labor Welfare Projects Corporation Hospital pp.1599-1607
Published Date 1973/12/1
DOI https://doi.org/10.11477/mf.1406203428
  • Abstract
  • Look Inside

The effect of hyperbaric oxygen (OHP ; 2ATA O2) on cerebrovascular tone was assessed by cerebro-vascular responsiveness to CO2 in 25 anesthetized ventilated dogs in which ICP had been increased by slow inflation of extradural balloons.

OHP reduced ICP only at the stage when the cerebral circulation was still responsive to CO2, as manifested by a rise in ICP (the result of the cerebral vasodilatation), and in these instances, normal responsiveness (both increased CBF and ICP) to CO2 was recovered by OHP. When the cerebral circulation was only responsive to CO2 with increasing ICP and failed to increase CBF, if the increased ICP was reduced by the adminis-tration of mannitol (1g/kg), no additional CO2 reactivities were appeared, but in the cases of OHP, normal CO2 responsiveness (both increased CBF and ICP) was observed in spite of the same level of ICP. These results would reveal that OHP improves cerebrovascular tone not only by reduc-tion of increased ICP, but also by oxygenation of cerebral hypoxia.

When CO2 failed to influence intracranial pres-sure at high level of ICP, OHP had no effects on the cerebrovascular tone. According to these ex-perimental results, we emphasize that OHP has beneficial effects on acute brain swelling by im-proving the cerebrovascular tone.

Concerning the effects of OHP on the cerebro-vascular tone, we discussed whether OHP would improve cerebral tissue hypoxia or arterial wall hypoxia by arterial hyperoxygenation.

Copyright © 1973, Igaku-Shoin Ltd. All rights reserved.


電子版ISSN 2185-405X 印刷版ISSN 0006-8969 医学書院