Gastric blood flow, tissue gas tension and microvascular changes during hemorrhage-induced stress ulceration in the pig.

Various features of blood supply to the gastric mucosa were studied in the piglet stomach during stress ulceration induced by hemorrhagic shock. Gastric blood flow, as measured by the radioactive microsphere technique, significantly decreased during shock, but no major change occurred in the gastric function of total cardiac output. There was no difference in the magnitude of the decrease of mucosal blood flow between the nonulcerating antral mucosa and the more readily ulcerating corpus or fundic mucosa. At the same time, a significant decrease in tissue partial pressure of oxygen and increase in tissue partial pressure of carbon dioxide occurred, but again no difference was observed between the antrum and the corpus. Microangiographic studies demonstrated a clearly diminished filling of the arterial and capillary bed of the gastric mucosa during shock, suggesting intense vasoconstriction, thrombosis of the mucosal blood vessels, or both. These changes were more prominent in the corpus portion of the stomach than in the antrum. At the site of mucosal lesions, the filling defects persisted even after the shock, suggesting permanent thrombosis of the blood vessels.