Oxygen saturation of the portal venous blood has been found to be higher than that of the systemic venous blood of anesthetized and unanesthetized dogs1,2 and human subjects.2-4 This has been observed in patients with and without liver disease. Regardless of the role of arteriovenous shunting in bringing about an elevated portal venous oxygen saturation, a number of other factors might conceivably have a part. This study was initiated in order to investigate several of them. It was our aim to learn the effect of the anesthetic state, of active body exercise, of digestion, and of hypoxia.
Materials and Methods
Adult mongrel dogs weighing from 11 to 18 kg were used. Anesthesia was induced by the intravenous administration of sodium thiopental. Tracheal intubation was carried out, and the lungs were inflated rhythmically with 100% oxygen by means of a mechanical respirator. The animals had received nothing by mouth