The Primary Culprits: What Causes NG Tube Clogs?
Clogging a nasogastric (NG) tube is a frequent and frustrating problem in both clinical and home care settings. Identifying the specific cause is the first step toward effective prevention and management. Blockages are typically attributed to three main factors: medication-related issues, inadequate flushing, and problems with the feeding formula itself.
Medication-Related Issues
Medications are a leading cause of NG tube clogs due to improper preparation or administration. Many common medications are not suitable for tube delivery and can form a sticky residue or precipitate inside the tube's narrow lumen.
- Improperly Crushed Tablets: Not all tablets can be safely crushed. Sustained-release, extended-release (XR), or enteric-coated medications are designed to dissolve slowly and must never be crushed, as this can destroy their intended delivery mechanism and cause immediate clogging. For crushable tablets, they must be ground into a very fine powder using a mortar and pestle and thoroughly dissolved in warm water before administration. Large, undissolved particles are a major source of blockages.
- Thick Liquid Medications: Certain liquid medications, including syrups and suspensions, can be too viscous to flow smoothly through the tube. They can leave a residue that builds up over time and constricts the tube's diameter. Always check with a pharmacist to see if a medication needs to be diluted before administration.
- Medication Incompatibility: Mixing incompatible medications together or with feeding formula can cause them to clump or precipitate, creating a solid mass that is difficult to clear. This is why medications must be administered one at a time, with a water flush in between.
Inadequate Flushing and Dehydration
Consistent and regular flushing is the best defense against tube occlusion, but it is often overlooked or performed incorrectly. Insufficient flushing is a major contributor to residue buildup.
- Neglecting Flushes: Flushing with water (typically 30-60 mL) is essential before and after giving formula or medications. During continuous feeds, a flush should be performed at regular intervals, such as every 4-8 hours. Skipping these steps allows residual formula and medication to dry and stick to the tube walls.
- Using Insufficient Water Volume: Using a small syringe (e.g., 10 mL) or too little water for a flush can be ineffective. A minimum of 30 mL of water and a 60 mL syringe is often recommended to create enough pressure and volume to clear the tube effectively.
- Overly Acidic Environment: Repeated checking of gastric residual volumes can pull acidic stomach contents into the tube, which can cause the protein in enteral formulas to coagulate and thicken. This is less of a concern with modern formulas, but routine, excessive residual checks should be avoided.
Formula-Related Issues and Tube Characteristics
Sometimes, the characteristics of the nutrition itself or the tube design can contribute to blockages.
- Formula Viscosity: While modern formulas are designed to be less prone to clogging, highly viscous or fiber-enriched formulas still carry a slightly higher risk, especially in smaller diameter tubes.
- Narrow Diameter Tubes: Fine-bore NG tubes, while more comfortable for the patient, are much more susceptible to clogging than wider-bore tubes because there is less internal space for the liquid to flow.
- Kinks and Compression: Mechanical factors can also cause a clog. A simple kink in the tubing, or external pressure from bedding or tape, can impede flow and cause the contents to thicken and block the tube.
Preventing Clogs: Best Practices for Caregivers
Prevention is always the best strategy for managing NG tube patency. A consistent, meticulous approach to care can minimize the risk of blockages and ensure smooth, uninterrupted feeding.
Proper Medication Administration
- Liquid First: Always prefer liquid forms of medication over tablets when available. Consult a pharmacist to identify suitable liquid alternatives.
- Crush and Dissolve Properly: For crushable tablets, use a dedicated pill crusher and a separate medication cup. Ensure the powder is fully dissolved in 30 mL or more of warm water before administering.
- Individual Doses: Give each medication separately, with a water flush of at least 15-30 mL in between each one. This prevents drug-drug interactions that can lead to precipitation.
- Stop Feeds: Always pause continuous or bolus feeds before administering medication and resume only after the final flush.
Regular Flushing Protocol
- Before and After: Flush the tube with 30-60 mL of water before and after every feed and medication administration.
- Consistent Schedule: For continuous feeds, flush the tube every 4-8 hours to prevent buildup.
- Use Warm Water: Use tepid or warm water, as cold water can cause formula to thicken, and excessively hot water can damage the tube.
General Care and Handling
- Keep it Kink-Free: Ensure the tubing is not kinked, bent, or compressed by the patient's position or equipment.
- Elevate Head: Keep the patient's head elevated to a minimum of 30-45 degrees during and for at least 30-60 minutes after feeding to reduce the risk of reflux and aspiration, which can also cause occlusions.
- Tube Replacement: If an old, brittle, or very narrow tube is a persistent problem, consult the healthcare team about a potential replacement with a larger bore or different type of tube.
Comparison of Safe vs. Unsafe Unclogging Methods
Attempting to clear a clog requires caution to avoid damaging the tube or injuring the patient. Here's a quick comparison of what to do versus what to avoid.
| Feature | Safe Unclogging Methods | Unsafe Unclogging Methods |
|---|---|---|
| Flushing Liquid | Warm water is the first and best line of defense. A pancreatic enzyme solution can be used with professional guidance for persistent clogs. | Never use acidic substances like cola or cranberry juice, as they can curdle formula proteins and worsen the blockage. |
| Administration | Use a 30-60 mL syringe with a gentle, push-pull motion. Allow warm water to soak in the tube for 15-20 minutes before repeating the push-pull action. | Do not apply excessive force to the syringe plunger, as this can cause the tube to rupture or dislodge. |
| Mechanical Action | Gently massage the tube with your fingers along its length to help loosen the blockage. | Never insert any object, such as a wire or swab, into the tube to clear a blockage, as this can cause perforation. |
| Persistence | If the initial gentle attempts fail, repeat the soaking process. Multiple attempts may be necessary. | Do not continue to apply force. If a blockage persists, escalate to a healthcare professional. |
Conclusion
Understanding why do NG tubes get clogged is vital for preventing the issue and ensuring consistent patient nutrition. Most clogs are preventable through diligent medication preparation, consistent and proper water flushing, and careful management of formula and tubing. When a clog does occur, the safest and most effective first step is a gentle flush with warm water. By following established best practices for prevention and management, caregivers and patients can significantly reduce the incidence of blocked NG tubes and ensure a smoother, safer feeding experience.
