Sometimes, people who are undernourished may not be able to eat or, when they try, find eating is difficult. Even if they have someone to help them eat, try to eat just a small amount at a time or eat food that has a lot of flavor, they may still need another way to supplement their nutrition or an alternative that provides all of their nutritional needs.
Definition
Parenteral nutrition describes giving someone the nutrition that they need via a tube inserted into one of their veins, explains Dr. Bruce Bistrian, chief of clinical nutrition at Beth Deaconess Medical Center, in "Harrison's Principles of Internal Medicine." It is usually used to supplement any food that they are able to eat, but it is not used if they are critically ill. The tube is called a catheter and is made of polyvinyl chloride, polyurethane or silastic.
Examples of Parenteral Nutrition Use
Partial parenteral nutrition gives some of the nutrition that a person needs every day, while total parenteral nutrition gives all of the nutrition that someone needs, writes Dr, David Thomas, professor of medicine at St. Louis University Health Sciences Center, in "The Merck Manual for Healthcare Professionals." Parenteral nutrition may be used at home or in the hospital for a child with some stomach or intestinal problems or for an adult with certain intestinal problems, such as ulcerative colitis, Crohn's disease or a blocked bowel.
Parenteral Nutrition and Liver Function
In "The Merck Manual for Healthcare Professionals," Thomas writes that more than 90 percent of the people who have parenteral nutrition have problems with their liver. Liver problems can happen to people of any age but usually occur in infants, especially ones who are premature, because their liver has not yet matured. They may develop a large liver or a high level of ammonia in their bloodstream. When amino acids are broken down, one product is ammonia. A normal liver can change ammonia, which is toxic to the nerves, to urea, but an immature liver may not be able to do so.
Preventing Liver Problems with Parenteral Nutrition
Research has shown that too many carbohydrates can lead to a liver problem, writes Dr. Leonard Gomella, chairman of the Department of Urology at Jefferson Medical College, in the "Clinician's Pocket Reference." Thus, to prevent liver complications, physicians limit a patient's dextrose sugar to 30 to 50 percent of total calories, make sure there is no overfeeding, give lipids as 10 to 30 percent of total calories and order parenteral nutrition for only 12 to 16 hours of the day. Lowering the amount of carbohydrates also helps prevent the development of a large liver.
References
- "Clinician's Pocket Reference"; Leonard Gomella and Steven Haist; 2007
- "Harrison's Principles of Internal Medicine"; Anthony Fauci, Dennis Kasper, Dan Longo, et al.; 2008
- The Merck Manual for Healthcare Professionals: Total Parenteral Nutrition (TPN)
