Flushing a nasogastric (NG) tube means pushing a small amount of water through it to keep it clear and prevent clogs. The process takes less than a minute and follows the same basic pattern every time: wash your hands, connect a syringe filled with water, let the water flow through, then close the tube. The details below cover the full process, including how much water to use, what type, and how to avoid common problems.
What You Need Before You Start
Gather your supplies so everything is within reach. You’ll need a feeding syringe (sometimes called a catheter-tip syringe), clean water, and a clean towel. If the tube is connected to a feeding pump, make sure the pump is turned off before you begin flushing. Having everything ready prevents you from needing to step away mid-flush with the tube open.
Step-by-Step Flushing Process
Start by washing your hands with soap and running water for at least 20 seconds, then dry them with a clean towel. This is the single most important step for preventing infection.
Draw up the prescribed amount of water into your syringe. Connect the syringe to the open port of the NG tube. If there’s a clamp on the tubing, open it. Let the water flow through by gravity first rather than forcefully pushing the plunger. A gentle, steady approach protects the tube from damage. If the water doesn’t flow on its own, apply light pressure on the plunger, but avoid forcing it.
Once all the water has passed through, close the clamp (if there is one), disconnect the syringe, and cap the feeding port. That’s the complete flush.
How Much Water to Use
For adults, a typical flush volume is 20 to 30 mL of water, though your care team may specify a different amount. For children, the recommended range is 5 to 20 mL, depending on the child’s age and the thickness of the feed being used. Thicker formulas leave more residue inside the tube and generally need a flush at the higher end of that range.
Newborns on frequent feeds or anyone on a fluid restriction may not need flushing at all, or may need a smaller volume. Always follow the specific volume your healthcare provider has prescribed, since every milliliter of flush water counts toward the person’s total daily fluid intake.
When to Flush
At minimum, flush the NG tube after every bolus feeding (a feeding given over a short period by syringe or gravity). For continuous feeds delivered by a pump, flushing after the last feeding of the day is often sufficient, though some care plans call for flushes every four to six hours during a continuous drip.
If medications are given through the tube, flush before the medication to clear any formula residue, then flush again afterward to make sure the full dose reaches the stomach and doesn’t sit in the tubing. When giving multiple medications, flush between each one so they don’t interact inside the tube.
Tap Water vs. Sterile Water
For most people, plain tap water is safe and effective for NG tube flushes. A review of the clinical evidence found that tap water worked as well as sterile water, and many hospitals have updated their policies accordingly to recommend tap water as the default. Sterile water is reserved for situations where there are specific concerns about tap water safety, such as a boil-water advisory in your area or a patient with a severely weakened immune system. Your care team will tell you if sterile water is necessary.
Positioning During a Flush
The person receiving the flush should never lie flat. Lying flat increases the risk of stomach contents traveling backward into the throat and lungs, a serious complication called aspiration. Keep the head of the bed raised to at least 30 degrees at all times when the NG tube is in use. Sitting upright is even better during a flush or feeding. If the water isn’t flowing well, slightly adjusting the person’s position (shifting from reclined to more upright, for example) can sometimes improve flow without needing to push harder on the syringe.
What to Do If the Tube Feels Blocked
If you meet resistance when flushing, don’t force the syringe. Excessive pressure can damage the tube or dislodge it. Try these steps first:
- Reposition the person. Sometimes the tube tip presses against the stomach wall, and a small position change frees it.
- Use warm water. Slightly warm (not hot) water can help dissolve formula residue that has thickened inside the tube.
- Gently pull back, then push forward. A small back-and-forth motion with the syringe plunger can loosen a partial clog.
If the tube still won’t flush after these attempts, contact your healthcare provider. A tube that can’t be cleared may need to be replaced.
Tracking Flush Volumes
Every flush adds fluid to the person’s intake, so it needs to be recorded. Write down the volume of each flush on whatever fluid balance sheet or log your care team has provided. In a hospital or clinical setting, flush volumes are documented alongside medication and feeding volumes on the fluid balance record. At home, a simple notebook works. Accurate tracking helps the care team manage hydration and avoid fluid overload, which is especially important for people with heart or kidney conditions.