Tissue and Blood Acidity

Abstract

This paper deals primarily with effects of low alveolar oxygen on oxidation, and resulting changes in acid metabolism, coupled with the impairment of transport of acid and its elimination in the lungs.

Low oxygen mixtures (3 to 12 per cent) were administered by normal ventilation, which permits control of ventilation by the animal, and by artificial ventilation, which maintains a constant movement of air. Changes in acidity of the arterial and venous blood were studied with the continuous method, and with the quin-hydrone and hydrogen electrodes.

Short administration of low oxygen (4 per cent) by normal ventilation elicited a sudden increase in alkalinity (0.1 to 0.2 pH) of the arterial and venous blood, followed by a rapid recovery on the re-administration of room air. Low oxygen administration elicited the usual increased pulmonary ventilation, which was followed by decreased ventilation on the re-administration of room air.

Similar administration of low oxygen by artificial ventilation, equal in volume to the preceding ventilation of room air, elicited markedly increased alkalinity of the arterial and venous blood. The increase in alkalinity, however, was smaller than that elicited on the administration of low oxygen by normal ventilation. The increased alkalinity of the blood resulting from administration of low oxygen may, therefore, be attributed to the washing out of carbon dioxide by excessive Ventilation, and to the liberation of alkali in the process of reduction of the hemoglobin. These conclusions are supported by the recovery curves on the re-administration of room air. Whereas the normal acidity of the blood was only slowly approached on re-administration of room air with normal ventilation, with artificial ventilation it was rapidly approached. Overshooting occurred with subsequent recovery to the previous normal acid value.