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Parenteral Nutrition

What is parenteral nutrition?

Parenteral nutrition (PN) is intravenous (IV) nutrition given through a catheter placed in a vein. It is used when the patient is not able to get all the nutrients they need by mouth or by enteral (tube) feeding. Parenteral nutrition is given as a liquid solution directly into the blood stream. It provides the calories and nutrients that a patient needs.

Parenteral nutrition may be used for partial or complete nutrition support. Complete nutrition support is known as total parenteral nutrition (TPN).

Different types of IV catheters can be used for parenteral nutrition. These include:

  • Peripheral venous catheter. For short-term parenteral nutrition, a catheter can be placed into a vein located in the arm. This is often called an IV or peripheral IV.
  • Central venous catheter. A catheter can be inserted by a surgeon into a large vein that leads to the heart. Central venous catheters include PICC lines, central lines, and ports. Many children have a central venous catheter for cancer treatments, and they can receive nutrition through a lumen attached to the catheter. Central venous catheters are preferred for long-term parenteral nutrition.

When possible, it is best to provide nutrition by mouth or tube feeding. These methods allow digestion to occur in a more natural way. In children with cancer, this is not always possible. Parenteral nutrition may be needed when:

  • The child’s digestive system is not working properly to absorb nutrients.
  • The child has had surgery of the digestive system.
  • The child’s intestines are blocked.
  • The child has severe vomiting or diarrhea.
  • The child has had problems with enteral nutrition (tube feeding).

Nutrients in the parenteral nutrition solution

The PN solution is prepared in a pharmacy. It is a sterile liquid that contains a mixture of key nutrients. The formula is customized to meet a patient’s specific nutrition needs based on factors such as age, weight, and health.

A TPN bag made of clear plastic and filled with white fluid

The parenteral nutrition solution is a sterile liquid that contains a mixture of key nutrients, customized to meet a patient’s specific nutrition needs.

Carbohydrates, proteins, and fats are 3 main nutrients that provide calories for energy and are used in different body functions.

  • Carbohydrates provide the body with calories for energy. In PN, carbohydrates are provided as glucose (sugar) in the form of dextrose.
  • Proteins are important to, build muscle, repair tissue, fight infection, and allow cells to function. Protein also provides calories to fuel the body. Proteins are made of amino acids. Some amino acids can be made by the body, but others must come from the diet.
  • Fats (lipids) provide calories and energy and are used for a variety of cell functions. Fats provided in PN are important to prevent essential fatty acid deficiency. Fats serve to protect organs of the body, help to maintain body heat, and store certain vitamins so that they can be absorbed by the body.

PN also provides:

  • Electrolytes, which are critical to bone, nerve, organ, and muscle function. Electrolytes that may be included in TPN are calcium, potassium, phosphorus, magnesium, sodium, chloride, and acetate.
  • Vitamins, which help your child grow and stay healthy. TPN generally includes a multivitamin with vitamins A, B, C, D, E, and K.
  • Minerals and trace elements, which are important to growth and body function. These may include zinc, iron, copper, chromium, manganese, and selenium.
  • Water, which ensures the proper amount of fluid to maintain normal hydration.

How parenteral nutrition is given

Parenteral nutrition is usually started in the hospital. A doctor, pharmacist, and registered dietitian work together to determine how many calories and other nutrients the patient needs each day. Blood tests are used to monitor response to PN. The PN mixture is adjusted as needed.

Usually, patients receive one bag of PN solution per day. PN comes in 2-in-1 (dextrose and amino acids) and 3-in-1 (dextrose, amino acids, and lipids) solutions. If the solution contains lipids, the bag will have separate chambers. The nutrients need to be mixed together by removing the dividing strip and gently kneading right before infusion. The solution is given by connecting the bag to the patient’s IV or central line and using an infusion pump. The pump is set to give the solution on a specific schedule.

Continuous PN is given all the time. This method is used when PN is first started. This allows the body to adjust to make sure that nutrition needs are met.

Cycled PN is given over specific time periods for less than 24 hours in a day. The pump is set to give PN on a cycle for a set number of hours, such as 20, 16, or 12 hours. As the cycle time is decreased, the rate of infusion is increased so that the overall PN is constant.

Benefits of cycled PN:

  • The patient gets to have time off the pump to move and participate in activities more easily.
  • Cycled PN can allow feelings of hunger. Continuous PN prevents hunger which can make it harder to transition to oral feeding.
  • Cycled PN can promote a more natural hormone response that occurs with meals.
  • There is a lower risk of PN-induced cholestasis, a health condition where there is a reduction or stoppage of bile flow.

Most patients have cycled PN overnight to allow a few hours of normal activity during the day. Depending on the device, the infusion pump can be worn in a backpack to allow more freedom of movement during PN infusion.

Problems and side effects of parenteral nutrition

Careful monitoring is needed to ensure proper nutrition and to prevent serious side effects. Many problems that occur with PN can be managed by adjusting the PN formula or schedule. It is also important to take good care of the central venous catheter to prevent infection. Proper hand washing and using aseptic technique when connecting and disconnecting PN are important.

Possible complications of PN include abnormal glucose levels, liver problems, changes in electrolytes, vitamin or mineral deficiencies, and catheter-related problems including infection, thrombosis, or blockage. PN may also change the way some medications work.

A common problem with PN is hyperglycemia, or high blood sugar. Hyperglycemia can occur when the body cannot use glucose well enough and blood glucose levels rise above normal. This may happen when PN is given too quickly so the body cannot process the sugar. It can also be caused by an infection or a medicine such as a steroid. Symptoms of hyperglycemia include headache, feeling thirsty, weak, or nausea. To prevent problems such as hyperglycemia, the amount of carbohydrate (dextrose) in PN is increased gradually over several days. Hypoglycemia, or low blood sugar, is less common but can occur if PN is stopped suddenly.

Monitoring during PN may include tests to measure:

  • Levels of glucose in the blood or urine
  • Levels of electrolytes in the blood
  • Liver function tests
  • Blood triglyceride levels
  • Urine output
  • Body weight

Parenteral nutrition at home

Patients can receive PN at home. Before going home, family caregivers will be taught how to:

  • Store, handle, and activate (gently knead) the PN solution
  • Add the multivitamin and/or medicines to the infusion bag
  • Connect and disconnect from the pump
  • Use the infusion pump
  • Care for the catheter
  • Use aseptic technique to prevent infection
  • Test blood and/or urine for glucose
  • Address problems that might occur
  • Get medical help in an emergency

Tips for families

  • Plan for delivery and storage of the PN solution. Home infusion services may deliver a week’s supply of PN solution (up to 7 bags) at a time. Make sure there is enough storage space in the refrigerator and that it is clean. Do not store more than 3 bags on top of one another.
  • All PN bags should be stored in the refrigerator and protected from light. The refrigerator temperature should be between 36°F and 46°F. PN formula is good for 24 hours at room temperature. Bacteria can grow in the bag if not stored properly.
  • Remove the PN bag from the refrigerator about 2 hours before using.
  • Select a specific place to prepare the PN. Make sure your workspace is uncluttered. Use a hard surface that can be cleaned easily.
  • Connect PN at the same time each night.
  • Keep a list of supplies. Know how many items you have and when you need to order.
  • Store supplies in a set place so you can easily find what you need.
  • Keep a list of contact information including your doctor, pharmacist, dietitian, and home infusion company.
  • Plan ahead if you need to travel with PN. You will need to keep the solution refrigerated or in a cooler. Make sure you have all supplies for the duration of travel, and consider how you will charge the pump battery.


Reviewed: June 2018

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