Management of parenteral nutrition in critically ill patients

Artificial nutrition (AN) is necessary to meet the nutritional requirements of critically ill patients at nutrition risk because undernutrition determines a poorer prognosis in these patients. There is debate over which route of delivery of AN provides better outcomes and lesser complications. This review describes the management of parenteral nutrition (PN) in critically ill patients. The first aim is to discuss what should be done in order that the PN is safe. The second aim is to dispel "myths" about PN-related complications and show how prevention and monitoring are able to reach the goal of "near zero" PN complications. Finally, in this review is discussed the controversial issue of the route for delivering AN in critically ill patients. The fighting against PN complications should consider: (1) an appropriate blood glucose control; (2) the use of olive oil- and fish oil-based lipid emulsions alternative to soybean oil-based ones; (3) the adoption of insertion and care bundles for central venous access devices; and (4) the implementation of a policy of targeting "near zero" catheter-related bloodstream infections. Adopting all these strategies, the goal of "near zero" PN complications is achievable. If accurately managed, PN can be safely provided for most critically ill patients without expecting a relevant incidence of PN-related complications. Moreover, the use of protocols for the management of nutritional support and the presence of nutrition support teams may decrease PN-related complications. In conclusion, the key messages about the management of PN in critically ill patients are two. First, the dangers of PN-related complications have been exaggerated because complications are uncommon; moreover, infectious complications, as mechanical complications, are more properly catheter-related and not PN-related complications. Second, when enteral nutrition is not feasible or tolerated, PN is as effective and safe as enteral nutrition.