Stress ulcer prophylaxis has always involved a tradeoff.
Critically ill patients can develop stress-related mucosal disease and clinically important upper gastrointestinal bleeding. Acid suppression may reduce that risk.
But clinicians have worried about pneumonia, Clostridioides difficile infection, and whether prophylaxis is overused in patients with low bleeding risk.
The physiology starts with splanchnic hypoperfusion.
Shock, mechanical ventilation, coagulopathy, renal failure, hepatic dysfunction, and severe physiologic stress can impair mucosal defense. Acid-related injury may then contribute to bleeding.