Superior mesenteric blood flow during digestion in man.

The superior mesenteric blood flow was studied with a dye-dilution technique after catheterization of the superior mesenteric artery and vein during the digestive phase after intake of a mixed meal (700 kcal). The material consisted of 5 patients. Within 5 minutes of the end of the meal the superior mesenteric blood flow, on the average, was increased by 60%. The largest increase was 113% and was noted one hour after the meal. The vascular resistance of the superior mesenteric vessles had by then fallen to a mean value of 55% below the prefeed value. The portal venous pressure was only slightly increased. The cardiac output was increased in 2 but slightly decreased in the remaining 3 patients. The pulse rate, blood pressure and haemoglobin concentration were largely unchanged. The ratio of the superior mesenteric blood flow to the cardiac output increased from 12 to 22% during the digestive period. The findings suggest the occurrence of a redistribution of blood after a meal with an increase in the superior mesenteric blood flow.