Role of enteral nutrition and pharmaconutrients in conditions of splanchnic hypoperfusion.

In critically ill patients there is consistent evidence that significant benefits are achieved if nutrients are delivered within the gut compared with the parenteral route. However, in conditions related to gut hypoflux, enteral nutrition may play a double role in counterbalancing the installed low-flow state. On the one hand, enteral-induced postprandial hyperemia may preserve the mucosal barrier and ameliorate immune competence; on the other hand, feeding by the gut may pose a theoretical risk of intestinal ischemia. Despite limited investigation, a strategic temporary minimal enteral nutrition with hypocaloric content has been recommended recently aiming to avoid the overfeeding syndrome and the menace of gut hypoperfusion. Under these conditions, the early luminal delivery of key nutrients such as arginine, glutamine dipeptides, antioxidants, and butyrate are an attractive option for this subset of patients. Arginine may prevent intestinal injury due to hypoperfusion but may harm the gut if ischemia is established. In contrast, glutamine may promote benefits in both conditions. Further investigations by randomized trials in this field are necessary.