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.

Specially trained health care providers show you and your caregivers how to prepare, administer and monitor PN at home. Your feeding cycle is usually adjusted so that PN infuses overnight, freeing you from the pump during the day. Portable pumps are available for those who need daytime infusion. Some people report a quality of life on PN similar to that of receiving dialysis.

Your PN care team may include:

  • Doctors. A surgeon will insert and, if necessary, remove the intravenous catheter used to infuse the PN. A gastroenterologist with special training in nutrition will supervise the medical aspects of your home PN and coordinate treatment with your primary care provider.
  • Nurses. Nurses will include a coordinator, a nurse educator who will train you to take care of your intravenous catheter, and staff nurses who are always available to answer questions and provide support.
  • Pharmacist. A clinical pharmacist will help you understand the use of drugs and nutrients, including the PN. The pharmacist contacts the home care company to arrange for you to receive supplies.
  • Dietitian. A registered dietitian will help you understand your diet and assist in planning appealing meals and snacks. If you need a special dietary product, the dietitian will advise you about its preparation, consumption, cost and availability.
  • Social worker. A social worker will obtain a social and financial history for your home PN team. Home PN is expensive, and many people need financial assistance. The social worker can suggest potential financial and community resources.
  • Home care company. A home care company will provide you with supplies, including the PN and clinical services. Your team helps you select a home care company.

You will have follow-up exams to assess your PN plan.

Depending on your reason for using PN, at some point your care team may help you decrease the amount you need. In some cases, your team will help to wean you off of PN entirely. Researchers at Mayo Clinic and elsewhere are studying both nutrients and drugs to help decrease the need for long-term PN.

Catheter types

PN is delivered through a thin, flexible tube (catheter) that has been inserted into a vein. At Mayo Clinic, doctors with special training in nutrition work with you to determine the type of catheter that's best for you. Mayo offers two main catheter options for delivering PN:

  • 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 PN.

Both types of catheter are usually inserted into a large vein leading to the heart. PN through this large vein can deliver nutrients quickly and lower the risk of catheter infection. The catheter insertion procedure is usually done after you've received heavy sedation or anesthesia.

Complications

Catheter infection is a common and serious complication of PN. Other potential short-term complications of PN 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. Your Mayo treatment team will monitor your PN formula closely and institute procedures to help prevent or treat these complications if already present.

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

  • Experience. Mayo Clinic provides total parenteral nutrition to nearly 1,500 people each year, some of whom receive treatment at home. Your care team is prepared with the experience, knowledge and resources to provide you with exactly the care you need.
  • Expertise. Mayo Clinic doctors have experience in several parenteral feeding methods. Your Mayo doctor will work with you and your caregivers to find the best option. Follow-up exams with your doctor and ongoing support from other care team members can help you achieve successful PN at home.
  • Collaboration. At Mayo Clinic, gastroenterologists, surgeons, pharmacists, internal medicine specialists, dietitians and nurse specialists work as a team to provide the care you need.

Mayo Clinic in Rochester, Minn., ranks #1 for digestive disorders in the U.S. News & World Report Best Hospitals rankings. Mayo Clinic in Scottsdale, Ariz., is ranked among the Best Hospitals and Mayo Clinic in Jacksonville, Fla., is ranked high performing for digestive disorders by U.S. News & World Report.

At Mayo Clinic, we assemble a team of specialists who take the time to listen and thoroughly understand your health issues and concerns. We tailor the care you receive to your personal health care needs. You can trust our specialists to collaborate and offer you the best possible outcomes, safety and service.

Mayo Clinic is a not-for-profit medical institution that reinvests all earnings into improving medical practice, research and education. We're constantly involved in innovation and medical research, finding solutions to improve your care and quality of life. Your doctor or someone on your medical team is likely involved in research related to your condition.

Our patients tell us that the quality of their interactions, our attention to detail and the efficiency of their visits mean health care — and trusted answers — like they've never experienced.

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Mayo Clinic works with hundreds of insurance companies and is an in-network provider for millions of people. In most cases, Mayo Clinic doesn't require a physician referral. Some insurers require referrals or may have additional requirements for certain medical care. All appointments are prioritized on the basis of medical need.

See information on patient services at the three Mayo Clinic locations, including transportation options and lodging.

Mayo Clinic researchers are studying methods of PN that can reduce the risk of complications and improve the quality of life of people who need intravenous feeding. Specific areas of interest include the effects of PN on liver disease and bone mineral density, and the ethics of long-term intravenous feeding.

See a list of publications by Mayo Clinic doctors on PN on PubMed, a service of the National Library of Medicine.

Oct. 28, 2014