Sources
Help build the largest human-edited directory on the web.
Submit a site - Become an editor
Wikipedia. Licensed under the GNU Free Documentation License.
Are you an expert in this subject? Join the discussion and share your knowledge at Wikipedia.org.
Total parenteral nutrition
From Wikipedia, the free encyclopedia
Total parenteral nutrition (TPN), is the practice of feeding a person intravenously, bypassing the usual process of eating and digestion. The person receives nutritional formulas containing salts, glucose, amino acids, lipids and added vitamins.
Contents |
 |
This section does not cite any references or sources. Please improve this section by adding citations to reliable sources. Unverifiable material may be challenged and removed. (October 2007) |
TPN is normally used following surgery, when feeding by mouth or using the gut is not possible, when a person's digestive system cannot absorb nutrients due to chronic disease, or, alternatively, if a person's nutrient requirement cannot be met by enteral feeding (tube feeding) and supplementation. It has been used for comatose patients, although enteral feeding is usually preferable, and less prone to complications. Short-term TPN may be used if a person's digestive system has shut down (for instance by Peritonitis), and they are at a low enough weight to cause concerns about nutrition during an extended hospital stay. Long-term TPN is occasionally used to treat people suffering the extended consequences of an accident or surgery. Most controversially, TPN has extended the life of a small number of children born with nonexistent or severely deformed guts. The oldest were eight years old in 2003.
The preferred method of delivering TPN is with a medical infusion pump. A sterile bag of nutrient solution, between 500 mL and 4 L is provided. The pump infuses a small amount (0.1 to 10 mL/hr) continuously in order to keep the vein open. Feeding schedules vary, but one common regimen ramps up the nutrition over a few hours, levels off the rate for a few hours, and then ramps it down over a few more hours, in order to simulate a normal set of meal times.
The nutrient solution consists of water, glucose, salts, amino acids, vitamins and (more controversially) sometimes emulsified fats. Long term TPN patients sometimes suffer from lack of trace nutrients or electrolyte imbalances. Because increased blood sugar commonly occurs with TPN, insulin may also be added to the infusion. Often though, an insignificant amount of insulin is added, sometimes 10 units or less in 2 liters of TPN. In actuality, the patient will probably get less than that. Occasionally, other drugs are added as well, sometimes unnecessarily.
Chronic TPN is performed through a central intravenous catheter, usually in the subclavian or jugular vein. Another common practice is to use a PICC line, which originates in the arm, and exends to one of the central veins, such as the subclavian. In infants, sometimes the umbilical vein is used.
Battery-powered ambulatory infusion pumps can be used with chronic TPN patients. Usually the pump and a small (100 ml) bag of nutrient (to keep the vein open) are carried in a small bag around the waist or on the shoulder. Outpatient TPN practices are still being refined.
Aside from their dependence on a pump, chronic TPN patients live quite normal lives.
The most common complication of TPN use is bacterial infection, usually due to the increased infection risk from having an indwelling central venous catheter. Liver failure may sometimes occur; a recent study at Children's Hospital Boston on the cause suggests it is due to a large difference in omega-6 to omega-3 ratio. When treated with Omegaven, a different fatty acid infusion (which is approved for limited use in the U.S.), two patients were able to recover from their condition.[1]
Two related common complications of TPN are venous thrombosis and priapism. Fat infusion during TPN is assumed to contribute to both.[2]
Another complication of TPN is non-anion gap metabolic acidosis.
- ^ Gura KM, Duggan CP, Collier SB, et al. Reversal of parenteral nutrition-associated liver disease in two infants with short bowel syndrome using parenteral fish oil: implications for future management. Pediatrics Vol. 118 No. 1 July 2006 p197-201
- ^ X Hebuterne, AM Frere, J Bayle, and P Rampal Priapism in a patient treated with total parenteral nutrition Journal of Parenteral and Enteral Nutrition Vol. 16 No. 2 1992 p171-174
- American Society for Parenteral and Enteral Nutrition
- TPN/PPN Calculator by Ryan Heinrick
- "Why does prolonged TPN cause liver damage in infants?", Children's Hospital Boston
- TPN-associated Liver Disease
- TPN Blogs on Nutrishare (a Home TPN provider)
- TPN Drug Information from MedlinePlus NIH Database
- TPN Care from the World Health Library