Total parenteral nutrition and its possible complications in the gastrointestinal tract

The gastrointestinal tract stands forth as the major regulator of nutritional health. If there is not an absorptive intestinal mucosa or other means of providing nutrients to other vital organs, the organism dies. The availability and development of newer methods of delivering nutrients, both enterally and parenterally, the development of nutrients that can now be given parenterally, (ie, glutamine, structured lipids), and the knowledge of nutrient-specific properties (ie, immune modulators), have made it easier and given us a greater variety of ways to sustain the patient. We continually find ourselves investigating the gastrointestinal tract, however, not only for its role in maintaining the nutrition state of the patient but also as a place where complications of nutrition support can be observed and where nutrition support can be used as a form of therapy, either primary or adjunctive. Lastly, as we have further refined these methods of support and support periods have become longer, we have become more aware of the complications, in particular, of total parenteral nutrition (TPN). This review will focus on a complication in the gastrointestinal tract of TPN—the continuing, perplexing problem of TPN-related hepatotoxicity, as well as other complications of TPN and a complication of intestinal integrity with TPN—the role of the intestinal mucosa in bacterial translocation.