Response of cereborspinal fluid pressure to hyperbaric oxygenation

The response of cerebrospinal fluid pressure (CSFP) to hyperbaric oxygenation (OHP) was investigated in 13 patients with acute cerebral damage and in dogs with or without experimentally produced cerebral damage. To elucidate the mechanism of the CSFP response, continuous measurements of carotid blood flow, arterial blood pressure, central venous pressure, and superior sagittal sinus pressure and CSFP were made before, during and after OHP. There was considerable variation in the response of CSFP to OHP in the patients, but three main patterns emerged; type I (nine cases), CSFP decreased at the beginning and rose again at the end of OHP, type II (two cases), CSFP fell with OHP and remained significantly lower than pretreatment level after it, and type III (two cases), CSFP showed little change with OHP. An animal without cerebral damage commonly showed a type I response of CSFP to OHP; the changes of CSFP at the beginning and end of OHP are mainly due to the changes of the cerebral blood flow. There may be two different actions of OHP on cerebral oedema, one decreasing cerebral oedema and another (mainly affecting the normal brain) producing cerebral oedema. Information obtained from the response of CSFP to OHP may be useful in judging the severity and pathophysiological state of cerebral damage.