OXYGEN AND CARBON DIOXIDE CHANGES IN ARTERIAL AND VENOUS BLOOD IN EXPERIMENTAL SPINAL ANESTHESIA WITH REMARKS ON THE CHOICE OF BASAL ANESTHETICS FOR BLOOD GAS STUDIES

¹ From the Surgical Research Laboratory, Boston City Hospital, Boston, Massachusetts

1. In experimental spinal anesthesia in cats under light ether the arterial oxygen is not depressed sufficiently to produce anoxemic effects.

2. In contrast the venous oxygen content is definitely reduced.

3. This increased arteriovenous oxygen difference is easily compensated for unless the phrenic or medullary centers are depressed or paralyzed.

4. It is suggested that serious respiratory embarrassment and fatal accidents are due to depression or paralysis of the phrenic mechanism or respiratory center, or to a combination of both.

5. Preliminary barbital anesthesia is an unsatisfactory drug to use for blood gas studies in that it depresses the oxygen content and increases the carbon dioxide content. In contrast these values under very light ether and nembutal are not altered when compared with the findings in the unanesthetized cat.