Tube feeding (enteral nutrition) is a way to deliver nutrients to a person who cannot or will not eat food or cannot or will not consume enough nutrients by mouth to meet their nutritional needs. A liquid formula is given through a tube and delivered directly into the stomach or small intestine.
Tube feeding may be used to feed people whose digestive tract is functioning normally but who are unable to eat by mouth or who are unable to eat enough by mouth to meet their nutritional needs. Such people include those with the following:
A poor appetite for a long time
Severe protein-energy undernutrition (a severe deficiency of protein and calories)
Coma or greatly reduced alertness
Difficulty swallowing caused by a stroke or other disorder that affects the brain and nerves
A head or neck injury or another disorder that makes people unable to eat by mouth
A serious illness or condition (such as a critical illness or burns) that increases nutritional needs
A breathing tube that prevents people from eating by mouth
If people are seriously ill, injured, or undernourished, they may be fed through a tube before surgery.
Compared with intravenous feeding, tube feeding has the following advantages:
It better preserves the structure and function of the digestive tract.
It costs less.
It probably causes fewer complications, particularly infections.
Procedure for Tube Feeding
Where a feeding tube is inserted usually depends on how long tube feeding is needed:
For less than 4 to 6 weeks: A thin plastic tube is passed through the nose and down the throat until it reaches the stomach (called a nasogastric tube) or the small intestine (called a nasoduodenal or nasojejunal tube).
For longer than 4 to 6 weeks or if the nose is damaged or deformed: The tube is inserted directly into the stomach (called a gastrostomy tube) or small intestine (called a jejunostomy tube) through a small incision in the abdomen.
Inserting a feeding tube through the nose
Nasogastric, nasoduodenal, and nasojejunal tubes can usually be inserted while the person is awake. The tube is lubricated and inserted into the nose and down the throat. A tube can cause gagging when it enters the throat, so the person is asked to swallow or is given water through a straw to help with swallowing. Swallowing can decrease or prevent gagging and help the tube pass down the throat.
Once the tube is down the throat and enters the esophagus, it can be easily slid into the stomach or small intestine. Doctors sometimes do imaging tests, such as an x-ray of the abdomen, to make sure the tube is correctly placed.
Inserting a feeding tube directly into the stomach or small intestine
When a feeding tube must be inserted directly into the stomach or small intestine, a percutaneous endoscopic gastrostomy (PEG) tube is often used.
Pascal Bachelet/BSIP/SCIENCE PHOTO LIBRARY
Before a PEG tube is inserted, people are given a sedative and sometimes a painkiller, usually intravenously. To help place the tube, doctors first insert a viewing tube (an endoscope) through the mouth and into the stomach or small intestine. (Before inserting the endoscope, doctors may spray a numbing agent on the back of the throat to suppress the urge to cough or gag.) The endoscope has a camera on its tip, enabling doctors to view the interior of the stomach and determine where to place the PEG tube. Doctors then make a small incision in the abdomen and insert the PEG tube. People must fast before the procedure, and eating and drinking are limited after the endoscopy is completed until the gag reflex returns.
If a PEG tube cannot be placed, a surgical procedure may be used to help doctors place the feeding tube directly into the stomach or small intestine. This procedure may be done in one of the following ways:
Using a viewing tube (laparoscope), which requires only a tiny incision just below the navel
Making a relatively large incision in the abdomen because doctors need to view the area through the incision so that they can place the tube in the correct place
After inserting a feeding tube
People with feeding tubes should be sitting upright or with the head of the bed elevated during a feeding and for 1 to 2 hours afterward. This position reduces the risk that they will inhale the formula into their lungs, and it allows gravity to help move the formula through the digestive tract.
Typically, a relatively large amount of formula (called a bolus) is given several times a day. However, if these feedings cause nausea, small amounts of formula are given continuously. With nasoduodenal, nasojejunal, or jejunostomy tubes, continuous feedings sometimes are given using an infusion pump.
Formulas for Tube Feeding
Several different formulas are available for tube feeding. Some can be made at home. Typically, a formula that provides a complete balanced diet is used, and formulas can be tailored to an individual person's needs. Some formulas are designed to treat a specific deficiency or disorder and may contain a single nutrient, such as fiber (to treat constipation or diarrhea), or different proportions of specific nutrients, such as proteins, fats, or carbohydrates. Most formulas are lactose-free or are made with lactose-free milk.
Some formulas contain proteins that are partially or fully broken down. These formulas are low in fat and contain much of that fat as medium-chain triglyceride (MCT) oil. These formulas are best for people who have trouble absorbing nutrients.
Specialized formulas are available for people with specific needs, such as diabetes or kidney disease. For example, carbohydrates may be restricted for people who have diabetes. Other formulas are specifically made for people who have healing wounds or other physical stressors.
Complications of Tube Feeding
Complications of tube feeding are common and can be serious.
Possible Problems With Tube Feeding
Problem | Possible Effects | Comments |
|---|---|---|
Tube-related | ||
Presence of the tube in the nose or mouth | Discomfort Damage to the nose, throat, or esophagus | A tube in the nose or mouth, particularly if large, can irritate tissues, causing pain and sometimes bleeding. In such cases, the tube is usually removed, and feedings are continued with a different kind of feeding tube. Sinuses can become blocked, making infections (sinusitis) more likely. |
Incorrect placement of the tube inserted through the nose or mouth | Damage to the affected area Coughing and gagging | Rarely, a tube in the nose or mouth goes down the airways rather than the esophagus. As a result, food can enter the lungs. When the tube is placed in the airways, people who are conscious and alert cough and gag. |
Incorrect replacement of a tube previously placed directly into the stomach or intestine | When a tube shifts out of place, it must be removed and placed again. If the tube was originally inserted directly into the stomach or intestine, reinserting the tube is more difficult, and the tube may be placed outside the digestive tract. Then food can enter the space around the abdominal organs (abdominal cavity). As a result, the membrane that lines that space may become infected—a serious infection called peritonitis. | |
Blockage of a tube | Inadequate nutrition | Thick formulas or pills can block a tube. Sometimes doctors can dissolve the blockage by flushing the tube with water or by adding certain enzymes or substances formulated to break down foods. |
Accidental expulsion of a tube | Inadequate nutrition | Tubes often come out accidentally. If a tube is still needed to provide nutrition, it must be replaced. |
Formula-related | ||
Intolerance of the formula | Diarrhea, digestive upset, nausea, and vomiting | The formula causes intolerable digestive symptoms in up to 20% of people being fed through a tube and in 50% of those with a serious illness. These symptoms are more common when feedings are given in large amounts (called boluses) given several times a day rather than continuously over longer periods of time. |
Diarrhea | Frequent, loose stools | Many liquid medications given through feeding tubes contain sorbitol, which can cause or worsen diarrhea. When diarrhea occurs, many of the nutrients pass through the digestive tract without being absorbed. |
Imbalances in nutrients | Abnormal levels of electrolytes Abnormally high levels of blood sugar (hyperglycemia) Too much fluid in the body (volume overload) | Doctors regularly measure weight (to check for too much water) and blood levels of electrolytes, sugar (glucose), and other substances. They then adjust the formula as needed. |
Other | ||
Backward flow of the stomach's contents into the esophagus (reflux) Excess secretions in the mouth and throat | Inhalation (aspiration) of the formula into the lungs, which causes coughing and choking and increases the risk of an infection such as pneumonia | If people have either of these problems, they may inhale the formula into the lungs even though the tube is placed correctly and the head of the bed is elevated. |
