A model of non-occlusive colonic ischemia (NCI) was produced in the dog, incorporating both moderately decreased systemic pressure and increased intralumenal colonic pressure. These factors may play an etiologic role in human NCI. When differences between mean systemic and mean distention pressures were 30 mmHg or less, severe mucosal injury occurred. In no case was the muscularis injured. Moderate systemic hypotension alone, or moderate colonic distention alone, did not produce significant colonic ischemic injury.
Colonic distention with pressures of 60 mmHg alone resulted in colonic mucosal necrosis, but these pressures are beyond those ordinarily encountered clinically, even in large bowel obstruction.
Angiography may be useful in demonstrating reduced flow to the colon during development of colonic ischemic injury. However, angiography is not a sensitive method in the diagnosis of nonocclusive colonic ischemic injury, once that injury has been established and inciting factors have subsided.