Blood changes in ether anesthesia

Abstract

During light ether anesthesia the bicarbonate content of the arterial blood falls, the carbon dioxide tension (determined directly by the tonometric method on the blood) rises, as does the hydrogen ion concentration. These phenomena indicate a state of uncompensated acidosis. The oxygen saturation increases, indicating that ventilation is accelerated in response to the stimulus of increased carbon dioxide tension. The acceleration does not, however, as under normal conditions, reach the height necessary to keep CO₂ tension and hydrogen ion concentration down to normal limits. It therefore appears that even in light etherization the respiratory center is markedly deadened.

In deep etherization the carbon dioxide tension rises still higher (over 80 mm. has been observed) and the P_H may fall to below 7.2. Respiration not only fails to be accelerated in response to the increased CO₂ tension but may even be so retarded that the oxygen saturation of the arterial blood falls below that normally found in venous. The blood tends to become concentrated.

Conductivity and chloride determinations on the serum indicate only minute changes. The only striking electrolyte changes appear to be the increase in hydrogen ions and the replacement of part of the bicarbonate HCO³ anions by the anions of acids as yet unidentified.