Vasopressor-Associated Non-Occlusive Mesenteric Ischemia in Critically Ill Adults: Mechanisms, Recognition, and Management

Abstract

Non-occlusive mesenteric ischemia is an acute failure of intestinal perfusion that arises without obstruction of the mesenteric
vessels, and in the intensive care unit it has become the most common form of acute mesenteric ischemia. It develops almost
exclusively in patients with circulatory shock who are receiving vasopressor support, and its mortality remains high largely
because the diagnosis is made late. This narrative review examines how vasopressor therapy and the shock state interact to injure
the gut, why the condition is so often missed in critically ill adults, and how it can be prevented and treated more effectively.
The review shows that the intestine is unusually vulnerable in shock because its circulation is among the first to be sacrificed
when blood flow falls, and this protective reflex can persist even after blood pressure has been restored. Vasopressors are
essential for maintaining perfusion pressure, but when they are escalated in a patient whose volume status or cardiac output has
not been corrected, they can deepen intestinal vasoconstriction and turn a reversible reduction in flow into bowel infarction.
The risk therefore reflects the way these drugs are used as much as the choice of drug itself. Recognition is difficult because
sedation and mechanical ventilation mask the abdominal pain and tenderness on which diagnosis traditionally depends, so
clinicians must instead respond to indirect signals of deterioration, particularly a rise in lactate or vasopressor requirement
that cannot otherwise be explained. Early contrast-enhanced computed tomography is the key diagnostic step, and catheter
angiography adds the ability to deliver vasodilator therapy directly into the mesenteric circulation. Effective management
depends on restoring blood flow rather than pressure alone, limiting vasoconstrictor exposure, resting and protecting the gut,
and proceeding to surgery with planned reassessment when bowel necrosis is suspected. The review also finds that outcomes
depend on wider system factors, including reliable access to imaging and interventional services, a secure supply of critical
medicines, and coordinated multidisciplinary pathways.
The review concludes that vasopressor-associated non-occlusive mesenteric ischemia is largely preventable and treatable
when it is anticipated. Careful vasopressor stewardship, a high index of suspicion, a low threshold for imaging and prompt
multidisciplinary action offers the best opportunity to reduce its mortality, while prospective research on risk prediction,
diagnostic biomarkers and catheter-directed therapy is needed to strengthen practice.