Gastrointestinal complications in critical care patients and effects of mechanical ventilation on the gastrointestinal tract

Patients in the intensive care unit (ICU) especially those who require mechanical ventilation are at increased risk for developing gastrointestinal (GI) complications such as bleeding, infection, and motility dysfunction. It is estimated that the prevalence of GI complications in those patients is approximately 50-80% and lots of those go undiagnosed. Complications can affect different parts of the GI system, including the esophagus, stomach, small intestine, large intestine, liver, and pancreas. Effects might include dysmotility, diarrhea, inflammation, infection, direct mucosal injuries, ulcerations, and bleeding, and it can be associated with high mortality rates. Moreover, it is believed that the GI tract has a significant contribution in the development of multiple organ dysfunction syndrome (MODS) in critically ill patients. Mechanical ventilation either alone or in association with other critical illness may have a multitude of effects on almost all the organs of the gastro-intestinal tract. Attention of those interaction and side effects can improve outcomes and potentially mortality. In this review, we describe the mechanisms proposed for mechanical ventilation induced GI complications and different GI complications which can affect the critically ill patient. Keywords: PEEP, Prone position, Dysmotility, GERD, GI bleeding, Ileus, Aspiration, Acalculous cholecystitis