Types of Enteral Feeding
Administration of Tube Feeding: Bolus and Continuous Drip
Equipment for Continuous Drip Feeding
Nutritional Considerations
Administration of Tube Feedings
Medication and Tube Feedings
Social Concerns with Tube Feeding
Transition to Oral Feeding
The types of enteral feeding, or tube feeding, are named according to the feeding route used, i.e., the site where the feeding tube enters the body and the point at which the formula is delivered: nasogastric, nasoduodenal, nasojejunal, gastrostomy, and jejunostomy. The decision of which type of feeding to use is based on the expected duration of tube feeding as well as physiologic and patient-related factors. The types of tube feeding most commonly used are nasogastric feeding and gastrostomy feeding.
The nasogastric (NG) tube usually is used when tube feeding will be required for a short time (i.e., less than three months) although in some cases it can be used for several years. The major advantage of nasogastric, nasoduodenal, and nasojejunal feedings over gastrostomy or jejunostomy feeding is they do not require surgery. Therefore, they can be started quickly and they can be used either for short periods or intermittently with relatively low risk.
The disadvantages of NG feeding include nasal or esophageal irritation and discomfort (especially if used long-term); increased mucus secretion; and partial blockage of the nasal airways. Nasogastric feeding may contribute to recurrent otitis media and sinusitis. With infants, NG feeding can decrease the suck/swallow mechanism. Two additional disadvantages are the possibility that the tube will perforate the esophagus or the stomach and the possibility that the tube will enter the trachea, delivering formula into the lungs. If formula enters the lungs, severe or fatal pneumonitis can result; therefore, it is essential to confirm that the NG tube is in the stomach before feeding begins
Gastrostomy tubes are well suited for long-term enteral feeding. Patient comfort with gastrostomies is an advantage over NG tubes. Gastrostomies do not irritate nasal passage, esophagus, or trachea, cause facial skin irritation, nor interfere with breathing. Gastrostomies are stable and more physiologic, allowing continued oral eating. There are button gastrostomies and other skin level feeding tubes that are easily hidden under a child's clothing. These require less daily care and interfere less with a child's movement. Gastrostomies use a large-bore tube, which allows a more viscous feedings and decreased risk of tube occlusion.
Disadvantages of gastrostomy feeding include the surgery required to place the tube, possible skin irritation or infection around the gastrostomy site, and a slight risk of intra-abdominal leakage resulting in peritonitis. Of special concern is the child with poor gastric emptying and/or severe reflux or intractable vomiting. These children have increased risk of aspiration. Please see section on aspiration.
Tube feeding directly into the jejunum (i.e., the middle section of the small intestines) is used for children who cannot use their upper gastrointestinal (GI) tract because of congenital anomalies, GI surgery, immature or inadequate gastric motility, severe gastric reflux, or a high risk of aspiration. The jejunal tube bypasses the stomach decreasing the risk of gastric reflux and aspiration.
However, even for children with gastric retention and a high risk of aspiration, there are disadvantages to jejunal feeding. First, nasojejunal tubes and jejunal tubes passed from a gastrostomy to the jejunum are difficult to position and may dislodge or relocate; their position must be checked frequently by X-ray. A jejunostomy reduces problems of tube position. Second, jejunal feedings bypass the digestive and anti-ineffective mechanisms of the stomach. Third, they require continuous drip feeding which results in limited patient mobility and decreased ability to lead a "normal" life. Finally, when compared to gastric feedings, they carry a greater risk of formula intolerance, which may lead to nausea, diarrhea, and cramps. Intact nutrients may be given if the feeding is given in the proximal intestine, but elemental or semi-elemental feeding are required if the feeding is delivered more distally. These formulas are more expensive.
Tube feedings can be administered by bolus feedings, continuous drip feedings or a combination of the two. The best is a combination of oral and tube feeding that fits into a child and family's schedule. Many of the complications of tube feeding arise from improper administration of formula.
Bolus feedings are delivered four to eight times per day; each feeding lasting about 15 to 30 minutes. The advantages of bolus feedings over continuous drip feeding are that bolus feedings are more similar to a normal feeding pattern, more convenient, and less expensive if a pump is not needed. Furthermore, bolus feedings allow freedom of movement for the patient, so the child is not tethered to a feeding bag.
The disadvantages of bolus feedings are that they are aspirated more easily than continuous drip feedings, and in some children, they may cause bloating, cramping, nausea, and diarrhea. It may not be practical to bolus feed a child when the volume of formula a child needs is large or requires that the child needs to be fed around the clock.
Continuous drip feeding may be delivered without interruption for an unlimited period of time each day. However, it is best to limit feeding to 18 hours or less. Feeding around the clock is not recommended as this limits a child's mobility and may elevate insulin levels contributing to hypoglycemia. Commonly, it is used for 8 to 10 hours during the night for volume-sensitive patients so that smaller bolus feedings or oral feeding may be used during the day. Continuous drip feeding is delivered by either gravity drip or infusion pump. The infusion pump is a better method of delivery than gravity drip. The flow rate of gravity drip may be inconsistent and, therefore, needs to be checked frequently.
One advantage of continuous feeding over bolus feeding is that it may be tolerated better by children who are sensitive to volume, are at high risk for aspiration, or have gastroesophageal reflux. Continuous feeding can be administered at night, so it will not interfere with daytime activities. Continuous feeding increases energy efficiency, allowing more calories to be used for growth. This can be important for severely malnourished children. When feedings are delivered continuously, stool output is reduced, a consideration for the child with chronic diarrhea. Continuous infusions of elemental formula have been successful in managing infants with short bowel syndrome, intractable diarrhea, necrotizing enterocolitis, and Crohn's disease.
A disadvantage of continuous feeding is that the child is "tied" to the feeding equipment during the infusion, although feedings can be scheduled for night time and naptime feedings. Additionally, continuous feeding is more expensive because of the cost of the pump and additional feeding supplies which may be necessary. A child's medication needs to be considered as continuous feeding may interfere with serum concentration of some drugs.
When choosing a feeding tube, the following factors should be considered: the patient's age and size, the viscosity of the formula to be used, and the possible need for a pump. For nasogastric feeding, the smallest bore tube in a soft material will minimize patient discomfort. Large-bore tubes partially block the airways, may interfere with the function of the gastroesophageal sphincter, and may irritate the nose and throat. Tubes size 8 French or smaller are usually used for children. The size refers to the outside diameter of the tube; one French unit equals 0.33 mm. Tubes this small cannot accommodate thick or viscous feedings (e.g., homemade blenderized formula or commercial formula containing fiber).
Most of the tubes now available are made of polyurethane or silicone, both of which remain soft and flexible over time; these tubes are usually weighted at the end for easier nasogastric insertion. The more flexible tubes are difficult to place without using a stylet. Nonweighted tubes may be displaced during gagging, vomiting, or coughing spells; however, they are used regularly and without difficulty for intermittent feedings in newborns.
Skin level gastrostomy feeding devices such as the Baard button gastrostomy or MIC-KEY are available. They allow feeding tubes to be attached only when the child is being fed. These devices are easily hidden under a child's clothes without tubing extending from stomach. They may be placed surgically in the stomach wall or after a gastrostomy tube has been placed.
There are many different enteral infusion pumps, varying in complexity, flow rate, and cost. Pumps can be rented from suppliers of medical equipment; however, for long-term use, it is less expensive to buy a pump. When deciding which type of pump to use, there are various considerations: availability, accuracy, cost, and ease of maintenance. The portable, battery-operated Kangaroo Pet Enteral Feeding Pump allows the child to attend school or go on outings. The Kangaroo pump fits neatly into a backpack.
Many of the pumps require their own feeding sets, including a container for the formula and tubing to connect the formula container to the feeding tube. Reuse of feeding sets can help minimize the cost. After use, the formula container, drip chamber, and tubing should be carefully cleaned with hot soapy water and rinsed thoroughly to remove the formula residue, which can cause bacterial contamination. It is best to have two feeding sets so that one can dry while the other is being used.
To give the child more mobility during continuous feeding, the feeding set can be hung on an IV pole and connected to a long length of tubing. Alternatives are to hang the feeding set on a plant hook above the bed or crib, on a nail in the wall or bedpost, or on a sturdy lamp or clothes tree. When traveling by car, the pump can be placed on the back seat with the feeding set hanging from the clotheshook. Miscellaneous supplies include syringes, gauze, catheter adapters, and tape.
In order to determine energy and nutrient needs, nutritional status should be assessed before tube feeding is started. The following table outlines the requirements of normal infants and children for water. For energy, protein and other nutrient needs refer to the DRIs. Adjust as needed for individual patient and condition.
|
Weight |
Water |
|
|
cc/kg |
cc/lb |
|
|
STEP 1 |
||
|
For first 10 kg or 22 lbs., provide |
100-120 |
45 |
|
STEP 2 |
||
|
For second 10 kg or 22 lbs., provide |
50 |
24 |
|
STEP 3 |
||
|
For weight over 22 kg or 44 lb., add to the amount above an additional: |
20 |
10 |
These requirements are useful in formulating tube feedings for children with disabilities as long as any conditions that may alter the child's nutritional needs are taken into account. For example, cardiopulmonary stress may increase calorie needs, while decreasing tolerance to fluid volume; infection or the stress from surgery may increase both calorie and protein needs, and certain drugs may increase the requirement for specific vitamins or minerals. On the other hand, immobility tends to decrease calorie needs.
The only way to accurately evaluate an individual's caloric needs is to regularly monitor weight gain, growth, and actual caloric intake. If a child's caloric intake is inadequate, weight gain will be poor. If caloric intake is excessive, weight gain will be higher than that desired for linear growth. Factors that may change caloric needs include illness, increased seizure activity, surgery, increase in therapy or return to school, or changes in medication.
Children who have been chronically underweight while on oral feedings often gain excessive weight when put on tube feedings, sometimes to the point of obesity. In these children, two factors may be coming into play: oral-motor problems that interfere with adequate caloric intake by means of oral feeding, and caloric needs that are lower than expected. Cases such as these illustrate the necessity of routinely monitoring weight and caloric intake in tube-fed children.
Older children with delayed growth due to inadequate calories may have delayed puberty. With adequate calories provided enterally they may begin to experience puberty and its body changes into their 20s. These changes need to be assessed when determining calorie needs so weight gain is appropriate.
Water must be provided in sufficient quantities to replace fluid losses and allow for normal metabolism. Fluid requirements depend on the following variables: urine output, sweating, vomiting, fever, stool pattern, environment, renal disease, cardiac anomalies, tracheotomies and medications. Constant drooling also contributes to fluid losses. Water requirements can be estimated using the table above, as long as the above variables are considered. Signs of dehydration requiring additional fluid include: constipation, decreased urine output, strong smelling or dark urine, crying without tears, dry lips and skin, or sunken eyes.
Patients who rely on tube feedings as their sole source of nutrients are at risk for electrolyte imbalances, which may result in serious medical complications (e.g. hyponatremia, hypernatremia, hypokalemia, hyperkalemia, dehydration and cardiac arrythmias). These patients should be evaluated regularly for sodium, potassium, and chloride status. The following Dietary Reference Intakes (DRIs) provide guidelines for a safe and adequate intake of electrolytes.
|
Age |
Sodium (g/d) |
Chloride (g/d) |
Potassium (g/d) |
|
0-6 months |
0.12 |
0.18 |
0.4 |
|
7-12 months |
0.37 |
0.57 |
0.7 |
|
1-3 years |
1.0 |
1.5 |
3 |
To determine vitamin and mineral needs, the DRIs for age can be used as a base, unless the child's growth is markedly delayed. For the child with growth delay, the DRIs for height age can be used. The value of "height age" is obtained by finding the age at which the child's actual height would be at the 50th percentile on the CDC charts (See Growth Charts section). Children with inadequate caloric intakes, decreased absorption, and increased caloric needs should be considered for supplemental vitamins and minerals.
Vitamin and mineral requirements can be altered by medications (See Nutritional Impact of Medications). Other variables to consider are disease, previous medical and dietary history, and biochemical parameters.
In general, supplement needs of VLBW infants on enteral feedings are the same as those fed orally, please see section on Supplements.
For older children or those who require special attention to calcium, phosphorus, and iron, supplemental vitamins and iron can be given with feedings in the form of multivitamin-with-iron drops or crushed chewable tablets. Calcium can be provided by crushed antacid tablets of calcium carbonate (e.g., Tums - one regular Tums provides 200 mg Ca) or liquid calcium preparation (e.g., Titralac - one tsp. provides 400 mg Ca). Phosphorus can be provided by liquid Neutra-phos; 1 capsule provides 250 mg P. Note: This may have a laxative effect.
Trace elements should be evaluated for the patient on long-term enteral support. The risk of developing nutrient deficiencies increases with frequent vomiting or gastrointestinal disturbances. Children on long-term tube feedings need to be evaluated for fluoride intake, and may need to be supplemented. This will require a prescription from the child's physician or dentist. Children with cystic fibrosis or anomalies of the distal ileum and ileocecal valve may fail to absorb fat-soluble vitamins or to reabsorb bile salts.
All children who are receiving enteral feedings should be monitored routinely by a dietitian who has experience in pediatrics.
Please see section on Infant Formulas and Breastfeeding for information that applies to infants less than 12 months corrected age. For information about products for enteral feeding for all children, please see section on Enteral Feeding Products for Children.
Infants who are beginning tube feedings with isotonic formulas or breast milk may be started at small volumes. Volume is gradually increased as the infant demonstrates tolerance. In the hospital, fluid needs are usually assured by IV fluid administration during this process.
Children beginning tube feedings may be started at full strength isotonic formulas or breast milk, given in low volumes. See recommendations below. Hypertonic formulas should be started at half strength. Children who have had no oral feedings for a long period of time or have a history of formula intolerance such as premature infants or children with short-gut, may require half-strength formula initially with gradual increases to full strength. In general, if a child needs diluted feedings, it is best to increase volume to make sure the child meets fluid needs then gradually increase concentration as the child can tolerate. Do not increase concentration and volume at the same time. Frequent adjustments may be necessary to help child and family adjust. It is best for feeding schedule to revolve around family schedule than the other way around.
Schedule to initiate enteral feeds:
|
Age |
Volume |
|
Infants |
10 ml/hour |
|
Child 1-5 year |
20 ml/hour |
|
Child 5-10 years |
30 ml/hour |
|
Child >10 years |
50 ml/hour |
Advance rate as tolerated to goal rate to meet child's nutritional needs. Increase volume every 4-12 hours, and monitor carefully for tolerance. Tolerance is defined as absence of diarrhea, abdominal distension, vomiting or gagging.
The physician may require residuals to be checked on new tube feeding patients or when the child switches formula or medicine. To check residuals, attach syringe to feeding tube and pull back stomach contents. If residuals are >25-50% of previous bolus feeding or 2 times the hourly volume for continuous drip feeding, reduce the feeding to the previous volume and advance at a slower rate. Return stomach contents.
Many tube-fed children require extensive drug regimens. Although the feeding tube is a convenient avenue for administering medicine, some medications are incompatible with the enteral products, interacting with specific nutrients, or causing the feeding tube to clog.
Elixirs and suspensions can usually be delivered through the feeding tube without a problem. Also, simple compressed tablets can be crushed and mixed with water or the formula. In contrast, syrups are incompatible with tube feedings because they tend to clog the tube unless diluted with water. Solid medicines such as sustained-action tablets or capsules or enteric-coated tablets should not be crushed and delivered through the tube; once crushed, their action may be altered or they may cause gastrointestinal distress.
Before a drug is given through the tube, the residual gastric volume should be checked. If the residual volume is greater than 50% of the volume of the last bolus feeding or 50% of the volume delivered during 1 hour of continuous feeding, the drug may not be absorbed effectively.
A benefit of tube feeding is delivery of medication by tube. The child does not refuse to swallow medication, drool, or vomit medication. Medications need to be given separately, with water flushes in between to prevent clogging the feeding tube. Check to see if medications can be given together without changing drug absorption. Feedings may decrease the absorption of a drug like phenytoin (Dilantin). Medications should not be mixed with feedings. If the child is on continuous drip feedings, stop the feeding. If the medication needs to be given on an empty stomach, stop feeding and wait 15-30 minutes before administering the drug. Then wait one hour before resuming feeding.
An important consideration in tube feeding is the family's ability and willingness to carry out the tube feeding program. Concerns include the availability and cost of equipment and formula, home sanitation and family hygiene, family support systems, and other psychosocial factors.
Before the child is discharged from the hospital, the caregiver(s) must be prepared for tube feeding. They should be thoroughly instructed on the following aspects of tube feeding: breast milk storage and handling, formula preparation, use and care of equipment, insertion of the tube, stoma care and emergency procedures. The caregivers should be encouraged to keep the following records in a notebook, which they should bring to each clinic visit: formula intake, stooling pattern, activity, behavior, medications, and instructions from medical staff. Before discharge, families should have a plan for expressing breast milk or obtaining and paying for formula, for obtaining and paying for enteral feeding supplies and for nutritional follow-up.
The caregiver(s) should be contacted daily for the first week the child is home, or until they feel secure with the tube feeding regimen. The follow-up can be provided by home visit, clinic visit, or telephone. The caregiver(s) should be given a phone number for 24-hour assistance regarding problems with tube feeding.
More than one family member or caregiver should be taught about the tube feeding to ensure continuity of the child's feeding program and to prevent isolation of the primary caregiver.
Family meals offer important learning experiences for children who are tube fed. It is important for the child to associate the satisfying feeling of fullness with the pleasant time of family meals, including social interactions, good smells and appearance of food. Even though the tube fed child may not experience the tastes and textures of oral feeding, he or she can benefit from the social experience. This is important if the child is to eventually transition from enteral to oral feeding.
When families are asked about enteral feeding their concerns include: finding a caretaker to tube feed their child; public ignorance about tube feeding; planning their social life around feeding schedule, and sadness over depriving a child of the pleasure of eating.
Feeding behaviors are often present before a child is tube fed and additional behaviors may develop while the child is tube fed. Patience is the key word. See section on Behavioral Problems Related to Feeding.
Transition to eating by mouth starts when the tube is first placed. It is important to follow an oral motor stimulation program with child who is tube fed. This is important so that the child can resume eating by mouth. The child needs to associate feeling in the mouth with a full stomach. For example: if you are hungry, you eat by mouth and feel satisfied.
Transition to oral feeding requires a team approach. Teams may include a physician, nutritionist, therapist, lactation consultant for breastfeeding and nurse. The initial step is to address readiness. The following questions are considered:
One of the first steps in transitioning is to promote hunger. The feeding schedule needs to be normalized into meals and snacks. After the feeding schedule is changed, calories are decreased by 25% and volume replaced with water to meet fluid needs. It takes time to change feeding behaviors. The longer the time a child goes without eating the longer it will take to transition to oral feeding. It is important to take small steps, letting the child feel that they are in control. The child has the benefit of using the enteral tube to meet nutritional requirements.
When do you remove tube? When the child demonstrates that she can eat adequate amounts of food to continue growth. It may be prudent to wait until the child demonstrates that they do not lose excessive weight with illness or during the winter cold and virus season.