Acid-Base Equilibrium Between Blood and Cerebrospinal Fluid

Abstract

In anesthetized dogs, respiratory acidosis was produced by inhalation of CO2-rich gas mixtures and respiratory alkalosis by overventilation. It was found that the pH of cerebrospinal fluid changed in parallel with the pH of blood in respiratory acidosis. In respiratory alkaiosis substantially identical results were obtained. After resumption of spontaneous ventilation, however, the pH of the cerebrospinal fluid remained more alkaline than the pH of the blood and for a longer time. Respiration was regularly depressed in that period. These results differ from those in exptl. metabolic acidosis and alkalosis descr. by other authors. In these conditions the pH and the alkali reserve of the cerebrospinal fluid change only slowly and moderately compared to the alterations in the blood. These differences between metabolic and respiratory acidosis and alkalosis are examined in view of the observations that the CO2/HCO3 ratio in the cerebrospinal fluid influences the activity of the respiratory center.