Tubes are constructed from silicone or polyurethane and can vary in length from 30 to 43 inches, with the shorter tubes used for nasogastric feedings. The diameters range from 5F to 16F catheters. Tubes may have weighted tips to help passage through the gut.
Percutaneous endoscopic gastrostomy tubes (PEGs) and percutaneous endoscopic jejunostomy tubes (PEJs) are generally used for long-term enteral feedings (>2 weeks). The placement further down in the gastrointestinal tract has a number of advantages: the diameter of the tube is larger (15F-24F catheters), which allows easier and faster passage of formulas and medications; the risk for aspiration is lower because of the decreased chance of migration of the tube up into the esophagus; the risk for sinusitis or nasoesophageal erosion is lower; and this route is more convenient and aesthetically pleasing to the individual because of the ability to conceal the tube. People anticipating long-term support may also consider a skin-level button gastrostomy or jejunostomy.
Assessment of need and ease of delivery are best done early. If the malnourished individual requires surgery for an unrelated event, a PEG or PEJ may be placed at that time to avoid an additional procedure.
Infusion Methods and Formulas
Enteral nutrition or tube feedings can be delivered at various rates. When possible, the bolus method is preferable because it mimics normal feeding, requires less time and equipment, and offers greater flexibility to the patient. The following is a summary of infusion possibilities:
Continuous or cyclic drip feeding
- Caloric/nutrient and free-water requirements need to be determined first to plan rate and time recommendations.
- Enteral feeding pumps provide reliable, constant infusion rates and decrease the risk of gastric retention.
- Assuming that no compounding factors are present, feeding into the stomach (25-30 cc/h) can start at a higher rate than feeding into the jejunum (10 cc/h); rates can be increased, with tolerance, every 4 to 6 hours until the rate reaches that needed to deliver the required caloric/nutrient needs.
- Continuous feeds can be cycled to run at night to allow greater flexibility and comfort. If it is physically possible, these nocturnal feeds can allow daytime oral or bolus feedings to meet nutritional goals and provide a more normal lifestyle.
Bolus and intermittent feeding
- Caloric/nutrient and free-water requirements need to be determined to plan the feeding schedule.
- Bolus feedings can be offered several times (3-6 times) each day; as much as 250 to 500 cc can be given over 10 to 15 minutes.
- Bolus feeding should be used ONLY when the endpoint of the tube is in the stomach; it should NEVER be used when feedings are delivered into the duodenum or jejunum. This precaution protects against gastric distention and dumping.
- A gravity drip from a bag or syringe with a slow push can be used to administer the formula.
- Diarrhea is a common side effect of this infusion method but can be controlled with a change in formula, additions to the formula, and a change in the amount of formula given over a finite period of time.