AUTOMATIC RECORDING OF PO2, PCO2, PH, NA AND K IN THE BLOOD AND THE BRAIN.

This report has two sections first, a detailed description concerning establishment of techniques for automatic recording of PO2, PCO2, pH, Na and K, and second, of application of the techniques to studies of cerebral circulation and metabolism in vivo. PO2, PCO2, pH and Na electrodes were constructed to our specifications. The PO2 electrode had a fine platinum cathode, surface of which covered with polyethylene membrane having a suitable thickness. The advantage was that the electrode could be calibrated easily and rapidly with gas at known oxygen tension, and was applicable for measurement of PO2 in absolute unit on the cerebral cortex. The pH electrode of McInnes type, the PCO2 electrode reported by Stow and the Na electrode fabricated from Eisenmans NAS11-18 glass had been tested in vitro with satisfactory results. Application of these electrodes was made in the manner in which their sensitive surfaces were lightly placed on cerebral cortex of cats and their output currents were recorded together with systemic arterial blood proencephalogram and electrocardiogram on a graph. The validity of the technique can be confirmed by alternation of these parameters in an expected manner under various conditions of cats, such as high gaseous tension of oxygen and carbon dioxide in the blood due to inhalation of O2-CO2 gas mixture. Author