About parenteral nutrition (PN)

What is parenteral nutrition?

Parenteral nutrition (PN), also called total parenteral nutrition (TPN), is a specialized form of liquid food. It is given to your child through a vein by intravenous (IV) infusion. PN provides liquid nutrients, including carbohydrates, proteins, fats, vitamins, minerals and electrolytes.

Why does my child need parenteral nutrition?

Your child will receive PN if they cannot absorb enough nutrition through their gastrointestinal (GI) tract or tolerate adequate food or fluids by mouth or through a feeding tube. Conditions that may require your child to have PN can include short bowel syndrome, digestive system disorders, bowel motility disorders, certain cancers, injury or trauma to the intestines and after surgery or procedures when a child cannot eat for a prolonged period.

PN can be given in addition to oral or tube feeding or as your child’s only source of nutrition. It will be provided at the hospital by your child’s health-care team or at home by a trained parent or caregiver.

How long will my child receive parenteral nutrition?

The length of time that your child may require PN can vary and depends on many different factors including their underlying diagnosis, age and intestinal anatomy. They may need to receive PN for a few weeks or months to several years. In some cases, they might require PN for life.

Key nutrients

PN contains all or most of the fluid, calories and nutrients that your child needs to grow and function every day.

Protein

Amino acids make up protein. Protein is an important part of all living tissue. The goals of providing PN include making sure your child receives enough amino acids for growth, tissue building and repair and to help fight infection.

Carbohydrate

Carbohydrates break down in the body into simple sugars, like glucose. Glucose is the only sugar found in the blood and is stored in the liver and muscles. The body uses glucose for energy and growth. Carbohydrates in PN is given in the form of dextrose.

Fat

Fats (lipids) are a concentrated form of energy, which means that a small volume of lipids provide a lot of energy. It also supplies essential fatty acids, which cannot be made in the body. Fatty acids help develop nerve cell structures, affect blood-clotting time and play an important role in the breakdown of cholesterol.

Electrolytes (sodium and potassium)

Sodium and potassium are essential minerals required by all tissues in the body to function. They are often referred to as electrolytes because they carry a small electrical charge that activates various cell and nerve functions. The main role of potassium is to help maintain normal levels of fluid inside cells. Potassium also helps muscles to contract and supports normal blood pressure. Sodium, its counterpart, maintains normal fluid levels outside of cells. These electrolytes help the kidneys function properly. They are important for energy production, fluid balance and growth.

Calcium, magnesium and phosphorus play a major role in building strong bones.

Magnesium as well as electrolytes will often be increased in PN for patients with loose stools, such as those with intestinal failure, as large amounts of electrolytes can be lost through stool.

Vitamins

Vitamins are a group of substances that are needed for normal cell function, growth and development. In PN, vitamins are added to the IV bags at the time of infusion. These vitamins help maintain normal blood vitamin levels and prevent deficiency symptoms. Vitamin levels are closely monitored to ensure doses are appropriate for your child.

Vitamin K

Vitamin K plays a role in developing strong bones and helps with normal blood clotting.

Trace minerals (selenium, zinc)

Selenium and zinc are essential micronutrients that have important roles in the body. Both selenium and zinc are added to PN. Some patients, such as those with intestinal failure, often require increased amounts of these micronutrients because they have difficulty absorbing them naturally and can lose trace minerals through their stool.

Fluids

Children on PN usually require more fluids than those whose digestive systems work normally. This is because their digestive tract is less able to absorb fluids, which leads to increased losses of fluid in their stools. The fluids lost need to be replaced in addition to what is needed for normal growth and bodily function. The more fluids your child needs to replace, the longer their PN sessions will need to be. They can also receive fluids through a separate IV solution.

How will my child receive parenteral nutrition?

Your child’s PN will be customized to their individual nutritional needs. It will be provided at the hospital by your child’s health-care team or at home by a trained parent or caregiver. The PN will be delivered by a pump through an intravenous (IV) line or a central venous access device (CVAD) directly to the blood stream. CVADs include:

• central venous lines (CVLs) inserted into either the jugular or femoral vein
• peripherally inserted central catheters (PICCs)
• ports

The type of device used to infuse PN depends on the length of treatment and the composition of TPN. Generally, short-term PN will be infused through an IV line, and long-term PN will be infused through a CVAD. PN administered at home will always be administered through a CVAD.

The number of days per week and hours per day that your child will receive PN will be customized to their needs and depend on several factors:

• your child's age
  
• your child's ability to tolerate solid foods and fluid by gut
• the number of calories your child requires
• the amount of fluid your child requires
• your child's ability to maintain normal glucose levels when off PN

Younger children with high stool losses and poor tolerance of gut feeds will require more time on PN support. Children who are eating and tolerating some foods and fluids will be able to have more time off PN support.

Cycling off parenteral nutrition

The goal of treatment with PN will be to cycle your child off PN completely. The number of hours off PN or IV fluids will depend on your child’s status. Being cycled off PN is beneficial for the liver and quality of life. However, too much time off can lead to dehydration, which can damage the kidneys over time. Achieving a balance is especially important.

As your child’s intestine adapts to absorb more nutrients, the amount of nutrients required in the solution will decrease. Cycling your child off of PN will be begin slowly, stopping the PN infusion for a few hours of the day. Eventually, your child may be able to take days off until the PN is stopped completely.

Early complications

Central line–associated blood infection (CLABSI)

Having a CVAD gives bacteria an easy route into the blood system, which can lead to blood infections. There is a risk of infections every time the CVAD is accessed. These infections are referred to as central line–associated blood infections (CLABSI). Using aseptic non-touch technique (ANTT) during central line care is essential to preventing the occurrence of a CLABSI. Recurrent episodes can affect many parts of the body and have a significant impact on quality of life due to prolonged admissions in hospital.

Central line thrombosis

A central line thrombosis is a blood clot that occurs in the veins that are used for CVAD placement. The development of clots related to central lines poses significant risk as CVADs are required for administration of PN. Some factors that contribute to the development of thrombosis include the location of the central line, the size of the line and the development of CLABSI.

IFALD: Intestinal failure–associated liver disease

Intestinal failure–associated liver disease (IFALD) can develop in children receiving TPN, and several risk factors contribute to its occurrence:

• infections
• prematurity
• absence of food through the GI system
• the composition of the TPN

Late complications

Metabolic bone disease

Metabolic bone disease is caused by changes in the way minerals are absorbed. Children on PN may not properly absorb minerals that are important to bone health such as calcium, magnesium and phosphorus. Other factors that contribute to bone disease include vitamin D deficiency, dehydration or loss of minerals (bicarbonate) in the stools.

Renal disease

Renal disease can occur due to long-term use of PN. Persistent dehydration, contamination of elements in TPN solutions and exposure to medications that are damaging to the kidneys are some of the factors that contribute to the development of renal disease.

Micronutrient and vitamin deficiencies

Children on PN may have decreased ability to absorb vitamins and minerals, which can lead to low levels of micronutrients. Deficiencies in micronutrients can occur with children on and off TPN support.

Standard and routine monitoring such as bloodwork and ultrasounds is very important to prevent complications on children who are on long-term TPN.

Monitoring

Growth (weight and height) monitoring must be done regularly to ensure children are receiving the nutrition they need through PN. Children on PN will also require regular bloodwork to monitor electrolytes and hydration.

Children on home PN require ongoing follow-up care by the home TPN team for monitoring and prevention of complications. The following are routine tests that are done to assess PN complications:

• routine bloodwork to check micronutrient and vitamin status
• chest X-rays to check for CVAD placement
• ultrasounds to assess blood vessels, kidneys and liver
• DXA scan to monitor bone mineral density (BMD)