Dynamics of changes in the acid-base equilibrium of arterial blood and the cerebrospinal fluid in conditions of natural hyperventilation and apnoea.

From investigations on 252 patients the dynamics of changes in the acid-base equilibrium of the cerebrospinal fluid (CSF) and arterial blood were assessed, in conditions of natural changes in breathing rhythm. Gasometric examinations were made several times during natural hyperventilation lasting 4, 5 or 6 min, depending on the examined group, and after apnoea lasting 30 s. The results indicate a specific autonomy of the CSF with respect to the blood, relating to such indices as pH, pCO2 and pO2, in conditions of natural changes in breathing rhythm. This is manifested to varying degrees by differentiation in time of occurrence, depth and direction of changes in the acid-base equilibrium indices in the CSF, relative to the corresponding indices in the blood. On this basis a number of groups were distinguished from among the patients investigated, in whom the clinical state appeared to correlate, to a certain degree, with the degree and direction of changes in the CSF. It is postulated that his specific autonomy of the CSF may be due to the action of regulatory mechanisms at the level of the nerve tissue.