In this post, I link to and excerpt from PedsCases‘ Approach to Nutrition Support: Tube Feeding, by Sierra.Casey Nov 20, 2020. This is an excellent brief resource on tube feeding.
All that follows is from the above resource.
This podcast presents an approach to the management of nutrition support in children as it pertains to tube feeding. Listeners will learn the indications, routes of administration, and formula types used in tube feeding. It also reviews writing nutrition orders and complications. The podcast was developed by Sierra Casey, a medical student at the University of Alberta, with the help of Dr. Jason Silverman, a pediatric gastroenterologist at the Stollery Children’s Hospital in Alberta.
- Podcast: Infant nutrition from 6 to 24 months
Developed by Sierra Casey and Dr. Jason Silverman for PedsCases.com. November 20, 2020
By the end of this podcast, listeners should be able to:
1. Discuss the indications for, advantages of, and contraindications to tube feeding.
2. Explain the routes of administration, delivery methods, and formula types used in tube feeding.
3. Write nutrition orders for a child including starting and weaning off tube feeds.
4. Describe some of the complications of tube feeding.
Let’s start with a case.
You are on your inpatient pediatrics rotation and you are called to admit Lucas, a 2-year-old boy with global developmental delay who presents with a two-day history of fever and cough and has a chest x-ray consistent with pneumonia.
You take a thorough history and find out that during the past two days he has been coughing a lot and breathing more rapidly. He has also been less active than usual. You
inquire about his eating, and his mother tells you that he often coughs and sputters while eating and drinking and has for most of his life. In the last two days he has also been eating and drinking much less than usual.
You discuss the case with your preceptor, and she agrees with your assessment that Lucas’ presentation is in keeping with aspiration pneumonia.
As you discuss your plan for Lucas’ admission, your preceptor has some questions for you: “Do you think Lucas is safe to feed orally, or will he need tube feeding? If he does need tube feeding, what type of tube and what type of formula would you choose for Lucas? Can you write some nutrition orders for him?”
The podcast returns to the case throughout the discussion. Please review the complete script.
What are the indications for tube feeding?
There are many reasons that a patient may need tube feeding. Generally, children who cannot feed orally or who cannot get enough calories through oral nutrition alone, should be fed enterally so long as their gastrointestinal tract is functioning.
One group of patients who need tube feeding are those with an impaired oropharyngeal phase of eating. For example, premature babies who have not yet developed suck and
swallow reflexes and therefore cannot be bottle or breastfed. Neurologic and motor dysfunction, such as in cerebral palsy, and upper GI abnormalities, like cleft palate, can
also impair the oropharyngeal phase of eating. Critical illness and mechanical ventilation may also make short-term tube feeding necessary because they prevent oral intake. Pediatric patients with drug-related nausea and vomiting, such as from
chemotherapy, may also benefit from at least temporary or partial tube feeding. Additionally, patients with acute or acute on chronic pancreatitis can benefit from tube feeding if they cannot tolerate oral nutrition.
Another group of patients who need tube feeding are those who cannot absorb adequate nutrition through oral feeding alone. Disorders of digestion, absorption, or GI motility such as short bowel syndrome, chronic diarrhea, chronic intestinal pseudo
obstruction, and liver disease fall into this category. Patients with other chronic illnesses such as cystic fibrosis, renal disease, congenital heart disease, and metabolic diseases often have increased caloric or nutritional requirements beyond what can be taken orally, and therefore may also require supplemental tube feeding.
Thirdly, tube feeding can be used to administer nutritional treatments or medications. Examples include the ketogenic diet in epilepsy or exclusive enteral nutrition for the treatment of Crohn’s disease. Tube feeding also allows providers to deliver fluids that cannot be taken orally. Tube feeding can even be used to deliver laxatives to treat severe chronic constipation.
Contraindications to tube feeding
Although there are a large range of patients who can benefit from tube feeding, there are a few cases in which patients should not be fed enterally.
These contraindications include:
1. Gastrointestinal ischemia, such as in necrotizing enterocolitis or toxic megacolon.
2. Severe and intractable vomiting and diarrhea.
3. Diffuse peritonitis, for example from a ruptured appendicitis.
4. Mechanical bowel obstruction
Routes of administration
Once you decide that a patient needs tube feeds, there are four main routes of administration to consider. Shorter term options include nasogastric or “NG” and nasojejunal or “NJ” tubes. Longer term feeding options include gastrostomy,
jejunostomy and gastrojejunostomy tubes.
Types of formulas used in tube feeds
Many different formulas are used in tube feeding. For infants, breast milk is the preferred nutrition source if possible.
Calorie content: Both breast milk and standard infant formulas typically contain about 0.67 kilocalories/mL. Infant formulas and breast milk may be fortified to increase their caloric density to 0.8 kilocalorie/mL or higher. Standard enteral formula used for tube feeding children older than 1 year contains 1 kilocalorie/mL. There are also more concentrated formulas that contain up to 2.5 kilocalories/mL. These concentrated formulas can be helpful in children with poor growth or who need to have their fluid intake restricted.
Nutrient content: There are several types of formulas that can meet the daily needs for micro- and macronutrients. The main differences between formulas are the extent to which the main macronutrients, protein, carbohydrates, and fats, are broken down.
Polymeric formulas or standard formulas are most commonly used and are usually well-tolerated. They contain intact proteins or polypeptides from either cow’s milk or soy. In terms of carbohydrate content, they include both disaccharide sugars and starches. Polymeric formulas also contain polyunsaturated fatty acids from sunflower, safflower, or soy oils.
Oligomeric formulas, also known as partially or extensively hydrolyzed formulas may be required if there is underlying gastrointestinal disease. They are also used for jejunal feeding. The proteins in oligomeric formulas are hydrolyzed, meaning they are broken down into shorter peptides. In terms of carbohydrate content, they are usually lactose free.
Elemental formulas are fully digested formulas that are typically only used when there is severe intolerance to other types of formulas. The protein in elemental formulas is broken up into individual amino acids and the carbohydrates are mostly monosaccharides. The fats in elemental formulas are mostly medium chain triglycerides, which aids in fat absorption.
In addition to polymeric, oligomeric, and elemental formulas, there are also specialized formulas that restrict or enhance the content of specific types of fat, carbohydrate or, in the case of metabolic disorders, individual amino acids.
Writing nutrition orders
Now how would you approach writing nutrition orders for an infant or child?
To start tube feeds, you first need to calculate the child’s daily energy needs, also called the total energy expenditure.
To calculate total energy expenditure, you first must calculate the resting energy expenditure, which is the number of calories that a sedentary, healthy child would need for a day. The resting energy expenditure is a function of the child’s weight, height, and age.
The resting energy expenditure is a function of the child’s weight, height, and age. There are several equations that can be used to calculate resting energy expenditure such as the Schofield, WHO, and Harris-Benedict equations. Daily
reference intake tables from the government of Canada are also available to calculate resting energy expenditure .
To get total energy expenditure, resting energy expenditure is multiplied by an adjustment factor, which accounts for the activity level and illness state of the child. In general, you would multiply the resting energy expenditure by 1.2 for well-nourished low-activity children, 1.5 for ambulatory children
with mild to moderate stress, and 1.7 for active children with catch up growth or severe stress.
Children who require tube feeds for longer than a few weeks should be monitored for growth parameters by plotting height and weight on a growth chart. Infants will require more frequent monitoring. If insufficient growth is achieved daily
calorie intake may need to be increased.
Finally, at some point the patient will either need to be weaned off tube feeds or will need a permanent tube. Weaning off feeds will depend on the route of administration of feeds and the indication for tube feeding.
Now let’s go back to the case. To refresh your memory, Lucas is a 2-year-old boy with a history of Global Developmental Delay who is being admitted to hospital with aspiration pneumonia.
You decide that Lucas needs tube feeding with an NG tube while in hospital. A standard polymeric formula is appropriate because Lucas is otherwise healthy and has no indication for an oligomeric or elemental formula.
You calculate his resting energy expenditure using his body weight, which is 12 kg, and multiply by an adjustment factor of 1.2 to get a total energy expenditure of 922 kilocalories per day. Next, you write orders for his feeding schedule. 922 kilocalories per day works out to 922 mL of formula per day if using 1 kilocalorie/mL standard formula. A bolus feeding schedule would be reasonable to start off with, so you decide to order 4
bolus feeds per day with 231 mL of formula given at each feed.
Complications of tube feeding
While there are several complications that can occur with tube feeding, life-threatening complications are rare.
Feeding tubes can become dislodged, occluded, or accidentally removed. Granulation tissue can occur at the site of gastrostomy or jejunostomy tubes. Rarely, there can be perforation of abdominal organs. Accidental pulmonary intubation on insertion of a nasogastric tube is also a complication to watch out for, making it important to confirm the placement of the tube after insertion.
Intolerance of feeds is a common complication of tube feeding. Symptoms of gastrointestinal intolerance of tube feeds include nausea, vomiting, diarrhea, and abdominal distention. If these symptoms occur, you may consider changing the feeding schedule, the rate of infusion, or the formula used.
A rare but serious complication of tube feeding is aspiration of gastric contents into the lungs. Risk factors for aspiration include severe GERD, sedation, mechanical ventilation and neuromuscular disease.
Refeeding syndrome is an important complication to look out for in patients who had a long period of fasting, malnutrition, or weight loss >10% . Refeeding syndrome is a combination of clinical complications that occur because of fluid and electrolyte shifts.
To quickly identify and treat refeeding syndrome*, patients with malnutrition being started on enteral feeds should be monitored with daily assessment of fluid status and serum electrolytes.
*Please see Refeeding Syndrome Guideline from The Royal Children’s Hospital Melbourne. Created by Liz Rogers (Dietitian) and Clinical Nutrition Team
Updated January 2017
That was a lot of information to take in! In summary:
Tube feeding is used to deliver nutrition beyond the esophagus. Tube feeding is indicated in patients with an impaired oropharyngeal phase of eating and in those who cannot take sufficient nutrition orally. Tube feeding is relatively inexpensive with fewer complications than parenteral nutrition. When choosing a formula for tube feeding, remember that most pediatric patients will tolerate standard polymeric formula. Many options exist for both short-term and long-term tube feeding.