The Blood Gas Content and Alkalinity of the Arterial Blood of Dogs during Carbon Monoxide Poisoning

Abstract

Carbon monoxide gas was applied to dogs, either hypodermically or through inhalation. About 500-1000 c. c. gas were hypodermically injected or air containing CO in 3, 1 or 0.05-0.08 per cent was given to inhale by means of a mask fitted on the muzzle.
Rate and volume of respiration, the CO₂, O₂, CO (when appeared) content and the CO₂ capacity of the arterial blood were determined, and thus the ratio of dissolved CO₂ to combined CO₂ was calculated; further the hydrogen ion concentration was directly electrometrically estimated.
When CO gas was subcutaneously injected in the above related dose or air containing CO in small concentrations given to inhale, the respiration underwent usually no essential alteration in either rate or volume, only seldom a slight augmentation was visible. In cases with air containing CO in high concentration the pulmonary ventilation accelerated definitely.
In all the cases the CO₂ content and the CO₂ capacity decreased, and commonly the latter more, so the ratio of dissolved CO₂ to combined CO₂ became greater. The figures of the hydrogen ion concentration obtained electrometrically also became smaller. Acidosis was thus a common occurrence. Intensity of blood changes ran parallel with that of poisoning. That in the injection experiment, conducted for only some five hours after injection, was not much greater than that of the inhalation of a small concentration of CO as 0.05-0.08%, but the animals invariably died on the fourth day after CO injection.
Sodium bicarbonate was intravenously administered to three dogs immediately after injecting CO hypodermically with definitely beneficial outcome in respect to the survival.
Double vagotomy did not materially alter the intensity of changes in the respiration, blood gas content and blood pH, due to CO inhalation.
Thus the present writer thinks that he was able to demonstrate in dogs under influence of carbon monoxide the lowering of CO₂ content in the arterial blood, regardless of the occurrence or not of pulmonary hyperventilation, the common occurrence of acidosis, the beneficial effect of alkali administration to the life of the animal, and further the non-interference of the double vagotomy upon the changes in blood and respiration due to CO poisoning.