Tube feedings, formally known as enteral nutrition (EN), deliver liquid nutrients directly to the stomach or small intestine when a person cannot consume food orally. A medical team selects the appropriate tube and formula based on the patient's condition, digestive function, and feeding duration. Knowing the names and functions of these devices and formulas is key for proper care.
Types of Tube Feedings by Placement
Feeding tubes are primarily categorized by where they are placed in the gastrointestinal (GI) tract and the duration of use. The name often reflects the path it takes (e.g., "naso-" for nose) and its destination (e.g., "-gastric" for stomach).
Short-Term Tubes
Short-term feeding tubes are typically used for periods of less than four to six weeks. They are non-surgically placed through the nose or mouth and are generally easier to insert and remove.
- Nasogastric (NG) Tube: This tube is inserted through the nose and guided down the esophagus into the stomach. It is used for patients with normal gastric function but difficulty swallowing due to conditions like stroke or a temporary illness.
- Nasojejunal (NJ) Tube: Similar to an NG tube, this tube is inserted through the nose but extends past the stomach into the jejunum, the middle section of the small intestine. It is used when feeding into the stomach is not tolerated, such as with delayed gastric emptying or a high risk of aspiration.
- Nasoduodenal (ND) Tube: This tube goes from the nose into the duodenum, the first part of the small intestine. Like an NJ tube, it is used for patients who cannot tolerate gastric feedings.
- Orogastric (OG) Tube: An OG tube is inserted through the mouth and into the stomach. It is most often used in infants or sedated adult patients where a nasal tube is not an option.
Long-Term Tubes
For tube feeding required for more than four to six weeks, a longer-term solution involving a surgically placed tube is preferred to prevent nasal and throat irritation and reduce the risk of displacement.
- Gastrostomy (G-Tube): A G-tube is a feeding tube surgically inserted directly into the stomach through an incision in the abdominal wall. This can be done via various methods.
- Percutaneous Endoscopic Gastrostomy (PEG): Placed using an endoscope, a camera-equipped instrument, for visualization.
- Radiologically Inserted Gastrostomy (RIG): Placed using X-ray guidance.
- Jejunostomy (J-Tube): This tube is surgically inserted directly into the jejunum, bypassing the stomach entirely. It is used for patients with compromised stomach function, such as severe reflux or gastric outlet obstruction.
- Gastrojejunostomy (GJ) Tube: This tube is placed through the stomach and extends into the jejunum. It has two ports, allowing for gastric venting (decompression) while delivering nutrition directly into the small intestine.
Categories of Tube Feeding Formulas
The liquid formulas used for tube feedings are classified based on their nutrient composition and the patient's digestive needs. A registered dietitian will recommend the most suitable formula.
- Standard (Polymeric) Formulas: These are the most common formulas, containing intact protein, carbohydrates, and fats that require normal digestive function. They are suitable for patients with a healthy gastrointestinal tract and come in various caloric densities. Examples include Isosource®, Jevity®, and Nutren®.
- Elemental and Semi-Elemental (Peptide-Based) Formulas: In these formulas, the protein and carbohydrates are already partially or fully broken down into smaller components (peptides or amino acids), making them easier to absorb. They are designed for patients with impaired digestion, malabsorption, or other GI issues. Examples include Peptamen® and Vivonex®.
- Blenderized Formulas: These are formulas made from real food ingredients, either commercially prepared or homemade. They are popular for patients who prefer a more natural diet and may offer benefits like reduced GI intolerance, though risks like bacterial contamination must be managed. Brand names include Compleat®.
- Disease-Specific Formulas: These are tailored for patients with specific metabolic conditions like diabetes, kidney failure, or respiratory disease. They have modified nutrient profiles to help manage these conditions, such as lower carbohydrate content for diabetes or adjusted electrolyte levels for kidney disease. Examples include Glytrol® and Novasource® Renal.
Methods of Delivery
Beyond the type of tube and formula, the method of administration is a key part of any tube feeding regimen. The two main modalities are bolus and continuous feeding.
- Bolus Feeding: This method involves delivering a larger volume of formula over a short period, several times a day, often with a syringe. It mimics a normal meal pattern and is typically used with tubes placed in the stomach, as the stomach is designed to hold large volumes.
- Continuous Feeding: With this method, formula is delivered continuously at a slow, steady rate over a longer period, usually 24 hours, via a feeding pump. It is often used for patients with tubes in the small intestine or for those with intolerance to bolus feedings.
- Intermittent/Cyclic Feeding: This is a hybrid approach where feeding occurs continuously for a set number of hours, often overnight, to allow for greater patient mobility during the day.
Bolus vs. Continuous Feeding Comparison
| Feature | Bolus Feeding | Continuous Feeding |
|---|---|---|
| Administration Method | Syringe or gravity bag | Pump over extended period (e.g., 24 hrs) |
| Administration Time | 5–15 minutes per feeding | Constant slow drip |
| Typical Tube Site | Gastric (stomach) | Post-pyloric (small intestine) or gastric for intolerance |
| Patient Mobility | Offers greater mobility between feedings | Requires connection to pump, restricting movement |
| Physiological Response | Mimics normal meal pattern, triggering hormone release | Less physiological, with more constant nutrient delivery |
| Aspiration Risk | Generally higher risk with large volumes | Lower risk due to slower rate |
| GI Tolerance | Can be less tolerated due to larger volumes | Often better tolerated for sensitive patients |
Conclusion
Understanding the specific names of tube feedings—from short-term nasogastric tubes to long-term gastrostomy and jejunostomy tubes—is fundamental for effective patient care. The choice of enteral formula, whether standard, elemental, or disease-specific, is also critical and is determined by the patient's individual needs. Furthermore, the delivery method, whether intermittent bolus or continuous pump-assisted feeding, plays a significant role in a patient's comfort and clinical outcomes. As every patient's needs are unique, consulting with a medical team, including a registered dietitian, is essential to determine the best approach for proper nutritional support. To learn more about clinical considerations for enteral nutrition, refer to the guidelines published by the American Society for Parenteral and Enteral Nutrition (ASPEN) and the Society of Critical Care Medicine (SCCM).
