Effects of Low Alveolar Oxygen and High Alveolar Carbon Dioxide on Rate of Flow of Cerebro-Spinal Fluid of the Dog.

Abstract

The fluid was obtained either by placing a cannula in the cisterna magna or by lumbar puncture, in most cases the former method being used. The rate of flow was recorded by the drop method.

High percentages of carbon dioxide in room air (8-14%) invariably increased the rate of flow, in one case reaching 1000%. This increase appeared promptly on administration of the gas, rapidly increased to a maximum, and persisted practically undiminished up to the readministration of room air, when the flow quickly returned to the preadministrational rate.

The effects of low oxygen are somewhat more complex. Low oxygen almost invariably caused a decrease in flow, followed, after prolonged administration, by a gradual increase, approaching, but practically never reaching, the preadministrational rate. The initial decrease in flow was usually preceded by a slight and very brief increase. When room air was again administered there was usually a brief but distinct decrease in flow, followed by a marked increase above the rate during administration of low oxygen and approaching the preadministrational rate.

These results seem to be in agreement with those obtained by Eddy 1 on salivary secretion. The effects of high carbon dioxide resemble the results of Gesell 2 on the rate of flow of lymph but the resemblance does not hold for low oxygen.