Intravenous (IV) nutrition is also called parenteral nutrition (PN). This treatment helps deliver nutrients to people who cannot receive food orally or through a feeding tube. IV nutrition can be used for patients of all ages and for a wide variety of medical issues.
Below, we’ll take a look at how parenteral nutrition works, when it’s used, how it prevents malnutrition and the potential risks involved in delivering nutrients through an IV.
What is IV for nutrition?
Parenteral nutrition involves having an intravenous (IV) catheter inserted into one of your veins to deliver nutrients directly into your bloodstream. This IV nutrition allows the nutrients to bypass the body’s normal digestion process.
When we ingest food, it moves through our gastrointestinal (GI) tract. But patients who have an illness or injury that compromises any part of their GI tract will need an alternate way of receiving nutrition in order to prevent malnutrition.
There are two types of parenteral nutrition: total parenteral nutrition (TPN) and peripheral parenteral nutrition (PPN). If you require TPN, your physician will place the IV catheter in your superior vena cava, the large vein that goes directly to your heart.
However, if you only require temporary nutritional assistance, your physician will administer PPN. PPN is delivered through a catheter inserted into a peripheral vein, most commonly the basilic vein on the inside of your elbow.
In both TPN and PPN, the catheter is hooked up to a bag containing the specific nutrients your body needs.
What is inside a parenteral nutrition IV?
Parenteral nutrition solutions are customized to each patient depending on the body’s needs. All parenteral nutrition IV bags include a sterile liquid (such as water or saline) for hydration and a mixture of key nutrients based on your medical condition, age, weight, and other health factors.
Parenteral nutrition IVs typically contain the following nutrients:
- Carbohydrates (dextrose) that provide the calories your body needs to produce energy.
- Protein (amino acids) to allow cells to function so your body can fight infection and repair tissue.
- Fats (lipids) provide energy, prevent fatty acid deficiency, protect organs, and store vitamins.
- Vitamins including A, B, C, D, E, and K.
- Minerals including zinc, iron, copper, chromium, manganese, and selenium.
Why do people need parenteral nutrition?
Patients who require parenteral nutrition are typically suffering from a condition that puts them at risk for malnutrition, such as:
Malnutrition is common among cancer patients whose tumors or treatments may lead to appetite loss, physical restrictions due to pain or nausea, or the malabsorption of nutrients.
Malnutrition can affect anywhere from 30 to 85% of cancer patients and is associated with poor health outcomes. But it can be avoided with IV nutrition that bypasses the gastrointestinal tract altogether.
There are many ways Crohn’s can impact your body's ability to digest food and absorb nutrients. For example, it can cause severe diarrhea leading to dehydration and the depletion of fluids, nutrients, and electrolytes. People with Crohn’s also commonly suffer from inflammation of the small and/or large intestine, which prevents the body from digesting food properly.
IV nutrition can deliver everything the body needs directly into the bloodstream without relying on a compromised digestive tract.
Short bowel syndrome
Short bowel syndrome (SBS) occurs when a patient does not have enough small intestine to absorb nutrients from their food. The small intestine is where most nutrient absorption takes place in healthy people. This condition can be caused by a birth defect or result from surgery to remove part of the small intestine.
TPN is a common treatment for SBS because it does not require the intestines to help the body absorb nutrients.
Ischemic bowel disease
Ischemic bowel disease is the result of decreased blood flow to the small intestine. Patients with the disease experience abdominal pain, nausea, and vomiting that can become worse after eating. By using TPN, the body no longer relies on the bowels to absorb nutrients.
The disease often requires long-term TPN, but the process can be used in the short term if a patient is a candidate for surgery to improve blood flow (such as a procedure to remove a blood clot).
Abnormal bowel function
If you have trouble passing stool or suffer from conditions such as irritable bowel syndrome or functional dyspepsia, it’s likely that your body will also have trouble processing the nutrients from food.
As with other GI disorders, TPN will ensure your body gets what it needs to continue functioning.
Digestive tract dysfunctions
Many conditions affect the digestive tract, from inflammatory bowel disease to diverticulitis. These conditions can cause bleeding, bloating, constipation, diarrhea, heartburn, nausea, and vomiting.
If your digestive tract is chronically dysfunctional, your gut will not be able to do its job by taking nutrients from food, causing malnutrition. While these diseases aren’t always severe enough to require TPN, you may need IV nutrition temporarily or once a day to ensure your body has what it needs to function.
Severe pancreatitis or certain stages of ulcerative colitis
Malnutrition can occur in patients with pancreatitis or advanced ulcerative colitis in two ways:
1) because the body cannot process the nutrients from food, or
2) because it improperly flushes out those nutrients with waste products (malabsorption). These diseases can also increase metabolic activity, requiring even more nutrients than usual.
TPN is not a standard treatment for these conditions unless they are extremely severe and the patient does not have a functional GI system. Enteral nutrition (the use of a feeding tube) generally leads to better patient outcomes.
In patients with advanced cancer of the abdominal cavity who cannot undergo surgery to repair an intestinal blockage, TPN may be the only way to help the body absorb nutrients. However, IV nutrition is only used when a feeding tube is not an option and if doctors don’t expect a patient’s gut function to return.
Birth defects of the digestive tract
Birth defects that occur anywhere along the GI tract can prevent a baby’s body from absorbing nutrients. While these are rare, they may require long-term TPN.
In these cases, TPN is recommended until the child is old enough to have surgery to repair the defects.
Chronic diarrhea in children
Diarrhea prevents the proper absorption of nutrients because food moves through the body too quickly. The condition can also cause dehydration.
TPN, PPN, and enteral nutrition can all be used in children at risk of suffering from malnutrition in order to prevent growth issues.
Risks involved in IV nutrition
While parenteral nutrition via an IV may be necessary in many cases, it is not risk-free. The body is built to receive nutrition through the gastrointestinal tract. So bypassing it in favor of intravenous nutrition is not ideal and can also lead to complications such as:
- Painful vein irritation and inflammation
- Blood clots
- Overhydration resulting in the build-up of fluid in the lungs
- Mineral and fluid imbalances
- Blood sugar issues, such as hypoglycemia
- Liver and bone disease
- Embolisms that result in a stroke
Catheter infection is also a common and serious complication of parenteral nutrition. To avoid infection, it’s crucial to clean tubing, access ports, catheters, and any other equipment used to administer IV nutrition.