Tube feeding may be used to feed people whose digestive tract is functioning normally but who cannot eat enough to meet their nutritional needs. Such people include those with the following:
A poor appetite for a long time
Severe protein-energy undernutrition Protein-Energy Undernutrition Undernutrition is a deficiency of calories or of one or more essential nutrients. Undernutrition may develop because people cannot obtain or prepare food, have a disorder that makes eating or... read more (a severe deficiency of protein and calories)
Coma or greatly reduced alertness
A head or neck injury or another disorder that makes them unable to eat by mouth
A serious illness (such as burns) that increases nutritional requirements
If people are seriously ill or undernourished Undernutrition Undernutrition is a deficiency of calories or of one or more essential nutrients. Undernutrition may develop because people cannot obtain or prepare food, have a disorder that makes eating or... read more , they may be fed through a tube before surgery.
Compared with intravenous feeding Intravenous Feeding Intravenous feeding is used when the digestive tract cannot adequately absorb nutrients, as occurs in severe malabsorption disorders. It is also used when the digestive tract must be temporarily... read more , tube feeding has the following advantages:
It better preserves the structure and function of the digestive tract.
Cost is lower.
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 tube). If the nose is damaged, the tube may be inserted through the mouth.
For longer than 4 to 6 weeks: The tube is inserted directly into the stomach or small intestine through a small incision in the abdomen.
Inserting a feeding tube through the nose
Nasogastric and nasoduodenal 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 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 intestine
When a feeding tube must be inserted directly into the stomach or small intestine, a percutaneous endoscopic gastrostomy (PEG) tube is often used.
Before a PEG tube is inserted, people are given a sedative and sometimes a painkiller, usually intravenously. Also, a numbing spray may be sprayed on the back of their throat to suppress the urge to cough or gag. Then doctors insert an endoscope through the mouth and into the stomach or small intestine. 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 test 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 feeding and for 1 to 2 hours afterward. This position reduces the risk that they will inhale the food, and it allows gravity to help move the food through the digestive tract.
Typically, a relatively large amount of food (called a bolus) is given several times a day. However, if these feedings cause nausea, small amounts of food are given continuously.
Several different formulas are available for tube feeding. Typically, a formula that provides a complete balanced diet is used. Some formulas are designed to treat a specific deficiency and may contain a single nutrient, such as proteins Proteins Carbohydrates, proteins, and fats are the main types of macronutrients in food (nutrients that are required daily in large quantities). They supply 90% of the dry weight of the diet and 100%... read more , fats Fats Carbohydrates, proteins, and fats are the main types of macronutrients in food (nutrients that are required daily in large quantities). They supply 90% of the dry weight of the diet and 100%... read more , or carbohydrates Carbohydrates, Proteins, and Fats Carbohydrates, proteins, and fats are the main types of macronutrients in food (nutrients that are required daily in large quantities). They supply 90% of the dry weight of the diet and 100%... read more .
Also, specialized formulas are available for people with specific needs. They include the following:
Concentrated formulas with less fluid for people whose fluid intake is limited
Fiber-enriched formulas for people who are constipated
Lactose-free formulas for people who are lactose-intolerant
Complications of Tube Feeding
Complications of tube feeding are common and can be serious.
Possible Problems With Tube Feeding
Presence of the tube in the nose or mouth
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
Thick formulas or pills can block a tube. Sometimes doctors can dissolve the blockage by adding certain enzymes or substances formulated to break foods down.
Accidental expulsion of a tube
Tubes often come out accidentally. If a tube is still needed to provide nutrition, it must be replaced.
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.
Frequent, loose stools
Many formulas used in tube feeding 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 Overview of Electrolytes More than half of a person's body weight is water. Doctors think about water in the body as being restricted to various spaces, called fluid compartments. The three main compartments are Fluid... read more
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, and other substances. They then adjust the formula as needed.
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 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.