Parenteral nutrition, often called total parenteral nutrition, is the medical term for infusing a specialized form of food through a vein (intravenously). The goal of the treatment is to correct or prevent malnutrition.

Parenteral nutrition provides liquid nutrients, including carbohydrates, proteins, fats, vitamins, minerals and electrolytes. Some people use parenteral nutrition to supplement feeding through a tube placed into the stomach or small bowel (enteral nutrition), and others use it by itself.

People whose digestive systems either can't absorb or can't tolerate adequate food eaten by mouth use parenteral nutrition. When used outside the hospital, intravenous feeding is called home parenteral nutrition. Using home parenteral nutrition may be necessary for weeks or months, or in some cases for life.

You may need parenteral nutrition for one of the following reasons:

• Cancer. Cancer of the digestive tract may cause an obstruction of the bowels, preventing adequate food intake. Cancer treatment, such as chemotherapy, may cause your body to poorly absorb nutrients.
• Crohn's disease. Crohn's disease is an inflammatory disease of the bowel that may cause pain, bowel narrowing and other symptoms that affect food intake and its digestion and absorption.
• Short bowel syndrome. In this condition, which can be present at birth or occur as the result of surgery that has removed a significant amount of small intestine, you don't have enough bowel to absorb enough of the nutrients you eat.
• Ischemic bowel disease. This may cause difficulties resulting from reduced blood flow to the bowel.
• Abnormal bowel function. This causes food you eat to have trouble moving through your intestines, resulting in a variety of symptoms that prevent enough food intake. Abnormal bowel function can occur due to surgical adhesions or abnormalities in bowel motility. These may be caused by radiation enteritis, neurological disorders and many other conditions.

Catheter infection is a common and serious complication of parenteral nutrition. Other potential short-term complications of parenteral nutrition include blood clots, fluid and mineral imbalances, and problems with blood sugar metabolism.

Long-term complications may include too much or too little of trace elements, such as iron or zinc, and the development of liver disease. Careful monitoring of your parenteral nutrition formula can help prevent or treat these complications.

Before the procedure

Parenteral nutrition is delivered through a thin, flexible tube (catheter) that has been inserted into a vein. Doctors with special training in nutrition work with you to determine the type of catheter that's best for you. The two main catheter options for delivering parenteral nutrition are:

• A tunneled catheter, such as a Hickman catheter, has a segment of tube outside the skin and another portion tunneled under the skin before it enters the vein.
• An implanted catheter is inserted completely beneath the skin and needs to be accessed with a needle in order to infuse the parenteral nutrition.

During the procedure

The catheter placement procedure is usually done after you've received heavy sedation or anesthesia. The catheter will be inserted into a large vein leading to the heart. Parenteral nutrition through this large vein can deliver nutrients quickly and lower the risk of catheter infection.

After the procedure

Your team will use laboratory testing to monitor your responses to parenteral nutrition. They will also periodically evaluate your fluid balance, the catheter site, and your ability to switch to tube feeding or normal oral feeding.

You will have follow-up exams to assess your parenteral nutrition plan. Depending on your reason for using parenteral nutrition, at some point your care team may help you decrease the amount you need. In some cases, your team will help wean you off it entirely.

Specially trained health care providers show you and your caregivers how to prepare, administer and monitor parenteral nutrition at home. Your feeding cycle is usually adjusted so that parenteral nutrition infuses overnight, freeing you from the pump during the day.

Some people report a quality of life on parenteral nutrition similar to that of receiving dialysis. Fatigue is common in people receiving home parenteral nutrition.