Enteral and parenteral nutrition are sometimes referred to as specialized nutrition support since nutrition is delivered by alternative methods other than food itself.
Enteral Nutrition: A patient who is unable to eat and drink but has a functional gastrointestinal tract may be a candidate for enteral nutrition or tube feedings. A tube is either inserted through the nose into the stomach or small intestine as a temporary measure, or a permanent enteral access device may be placed directly into the stomach or small intestine for long-term feeding. In either case, a formula containing all nutritional needs is infused into the tubes.
Parenteral Nutrition: If the gastrointestinal tract is not functional due to illness or injury, nutrition may be supplied through the veins. This is called parenteral nutrition (PN) or total parenteral nutrition (TPN). A catheter is placed into a vein and advanced until the tip of the catheter is lying close to the heart. A special formulation is customized for each individual and infused through the vein. Parenteral nutrition may be used on a short-term basis to facilitate postoperative healing or long-term in patients with permanent severe malabsorption.