Parenteral (intravenous) nutrition (PN), often called total parenteral nutrition (TPN), is the medical term for infusing a specialized form of food through a vein. Its goal is to treat or prevent malnutrition. It is typically used for people whose digestive systems either can't absorb or can't tolerate adequate food eaten by mouth. When used outside the hospital, intravenous feeding is called home PN. Using home PN may be necessary for weeks, months or lifelong, but most people who use it do so for less than one year.

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

You may need PN 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 may cause pain, inflammation, bowel narrowing and other symptoms that affect your ability to eat, digest and absorb food.
  • Short bowel syndrome. In this condition, which can be present at birth or occur as the result of surgery, 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 keep you from eating. 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.
  • Vomiting and nausea. If unmanageable, uncontrolled vomiting and nausea may require that you take in no food by mouth.
Oct. 28, 2014