A nasogastric (NG) tube is a thin, flexible tube inserted through the nose and down into the stomach, used to deliver nutrition and medication to patients who cannot consume them orally. While it is designed to facilitate nutritional support, the type of food administered and the method of delivery are critical safety considerations. This guide explores how and what can be safely put through an NG tube, with a strong focus on risk mitigation.
The Function of an NG Tube in Nutritional Support
NG tubes are a type of enteral nutrition, meaning they deliver nutrients directly to the gastrointestinal tract. This is crucial for patients with conditions affecting their ability to chew, swallow, or maintain adequate nutritional intake. For short-term needs, the NG tube is an effective and non-surgical option. Proper nutritional therapy can significantly improve patient outcomes, aid recovery, and reduce hospital stays.
Commercial Formulas vs. Blended Diets for NG Tubes
When considering what type of 'food' to administer, the distinction between commercially prepared formulas and homemade blended food is vital, especially for NG tubes. Commercial formulas are the standard of care for nasogastric delivery for several important reasons.
Risks of Blended Food in NG Tubes
While some families successfully use blenderized tube feeding (BTF) for other types of feeding tubes (like gastrostomy tubes), medical professionals often advise against it for NG tubes due to specific risks.
- Tube Blockage: NG tubes are much thinner and longer than gastrostomy tubes, with typical sizes being 6 Fr or 8 Fr compared to 12 Fr or wider for G-tubes. A blenderized diet, even when finely pureed, contains particles that can easily clog these narrower tubes. The required pressure to dislodge a clog can cause the tube to split.
- Aspiration: If an NG tube splits due to a clog, the contents can leak into the lungs, leading to a chest infection or aspiration pneumonia. This risk is significantly higher with NG tubes compared to other feeding tubes.
- Microbial Contamination: Homemade blends have a higher risk of bacterial contamination during preparation and storage. This is a major concern, as the food bypasses normal digestive processes that kill some bacteria, making food safety and hygiene protocols paramount.
- Nutritional Inconsistency: It can be challenging to ensure a homemade blend provides a balanced nutritional profile, including adequate calories, protein, and micronutrients. This can be especially problematic for patients with high or specific nutritional requirements. Unlike commercial formulas which are balanced and tested, DIY feeds can vary significantly in nutrient and electrolyte content.
How to Safely Administer Standard Formulas
For NG tubes, commercial liquid formulas are the recommended standard. These are nutritionally complete, have a consistent viscosity to prevent clogging, and are formulated to minimize bacterial growth. Administration can occur via two primary methods:
- Continuous Feeding: The formula is delivered slowly and continuously over a period, typically 24 hours, using an electric feeding pump. This is common for critically ill or bedridden patients.
- Bolus Feeding: The formula is given in larger amounts several times a day using a syringe or gravity drip. This method is more physiological, mimicking mealtime, and is preferred for mobile patients.
Comparison of Feeding Methods for NG Tubes
| Feature | Bolus Feeding (for standard formulas) | Continuous Feeding (for standard formulas) |
|---|---|---|
| Equipment Required | Syringe or gravity bag. | Electric feeding pump required. |
| Delivery Time | Administered over 5–20 minutes, several times daily. | Delivered at a steady, slow rate over 8–24 hours. |
| Physiological Effect | More closely mimics natural eating patterns. | Provides steady, consistent nutrition, less like natural meals. |
| Patient Mobility | Increases independence and mobility between feeds. | Restricts patient mobility due to constant pump connection. |
| Gastrointestinal Tolerance | Higher risk of gastrointestinal intolerance (cramping, distention) if infused too quickly. | Often better tolerated by critically ill patients or those with feeding intolerance. |
| Aspiration Risk | Increased risk of aspiration, especially in critically ill patients. | Lower risk of aspiration when the head of the bed is kept elevated. |
Best Practices for Feeding Through an NG Tube
- Proper Positioning: Always keep the patient's head and chest elevated to at least a 30-45 degree angle during feeding and for at least 30-60 minutes afterward. This helps prevent aspiration.
- Flushing: Flush the tube with water before and after every feed and medication administration to prevent blockages. A 30mL syringe is often recommended for regular flushing.
- Tube Placement Check: Always confirm proper tube placement before administering anything. This is typically done by a trained healthcare professional, but caregivers can be trained to check pH levels of aspirate.
- Medication Administration: Administer medications separately from feeds. Crush pills into a fine powder and mix with warm water, and flush the tube between each medication. Consult a pharmacist about medications suitable for crushing.
Addressing NG Tube Clogs
If a blockage occurs, follow these steps using a warm water flush technique:
- Check for Kinks: First, ensure the tubing isn't kinked.
- Warm Water Flush: Fill a syringe with warm water (15-30 mL) and attempt a gentle push-pull motion. Never use a lot of force, as this can damage the tube.
- Soak: If the push-pull method fails, allow the water to sit in the tube for 20-30 minutes to soften the clog, then try flushing again.
- Enzyme Solution: If the clog persists, a medical professional may recommend a pancreatic enzyme solution.
- Never Force It: If the clog cannot be cleared with gentle methods, the tube may need to be replaced by a healthcare provider.
Conclusion
While an NG tube is specifically designed to put food and medication directly into the stomach, it's crucial to follow medical guidelines for safe administration. For NG tubes, this means prioritizing commercially prepared, nutritionally complete formulas to minimize the risk of blockage and aspiration. Homemade blended diets, while sometimes suitable for wider gastrostomy tubes, pose significant safety risks for the thinner NG tube. By following proper procedures, including correct patient positioning, regular flushing, and using appropriate liquid nutrition, patients can safely receive the necessary nourishment to aid their recovery and maintain their health.
