Microcirculatory changes in the gastrointestinal tract of the hypoxic puppy: an electron microscope study.

Hypoxia and hypovolemia result in similar ultrastructural changes. These changes are characterized by aggregation of platelets and leukocytes in the vascular space, focal endothelial cell disruption, and appearance of increased amounts of perivascular edema, and loss of ultrastructural organization of the mucosal cell. These changes appear to relate to variations in blood flow to the mucosa of different areas of the bowel and to follow the distribution observed for necrotizing enterocolitis in the human infant.