When should tube placement be checked for patient safety?

October 16, 2025 •

4 min read

According to the National Patient Safety Agency, misread X-ray position checks for gastric tubes have led to significant complications and even death. Understanding when and how to correctly verify tube placement is a critical skill for preventing life-threatening aspiration pneumonia and ensuring patient safety.

Quick Summary

Correct nasogastric tube placement must be verified immediately after insertion with a chest X-ray and reconfirmed routinely before each use with pH testing or visual measurement. This is crucial for preventing aspiration.

Key Points

Initial X-Ray Confirmation: After initial insertion, a chest X-ray is the definitive 'gold standard' to confirm correct placement.
Routine Checks Before Use: Always verify placement immediately before administering any feed, medication, or water flush.
Regular Checks for Continuous Feeds: For continuous feeding, placement should be checked at regular intervals, such as every four to eight hours.
pH Testing is the Best Bedside Method: Testing aspirate for a pH of 5.5 or less is the most reliable bedside verification method for gastric placement.
Unreliable Methods Must Be Avoided: The 'whoosh test' (auscultation) and sole reliance on aspirate appearance or patient symptoms are not reliable indicators and should not be used for confirmation.
Monitor External Markings: Check for any movement of the tube from the external marking noted after initial X-ray confirmation, as this indicates possible displacement.
Re-check After Incidents: Placement must be re-checked after any incident that could cause dislodgement, such as coughing, vomiting, or increased patient agitation.

Initial Confirmation: The Gold Standard Method

Upon initial insertion of any enteral tube, such as a nasogastric (NG) tube, verification of correct placement is mandatory. The most reliable and universally accepted method is radiographic confirmation via an X-ray. This is considered the 'gold standard' because it offers a definitive visual confirmation of the tube's position within the stomach or small bowel, depending on the tube type. This initial check ensures the tube has not been accidentally placed in the respiratory tract, which can lead to fatal complications like aspiration pneumonia. After X-ray confirmation, the external tube length must be measured and documented at the insertion site, typically the nostril, using a permanent marker or tape. This marking serves as a baseline for all subsequent bedside checks.

Critical times to re-check tube placement

Tube placement can be compromised by patient coughing, vomiting, or movement, causing the tube to migrate. Therefore, ongoing verification is vital. Healthcare providers should routinely re-check tube placement under the following circumstances:

Before each use: This applies to every instance of administering a feed, medication, or water flush through the tube.
During continuous feeds: For patients receiving continuous feeding, verification should be performed at regular intervals, often every four hours, as per the American Association of Critical-Care Nursing recommendations.
After displacement concerns: Any time there is a clinical suspicion of displacement, such as after an episode of coughing, vomiting, or if the external tube marking has moved.
Upon patient distress: If the patient develops new respiratory symptoms, choking, or other signs of distress, the tube should be assumed to be misplaced until confirmed otherwise.

Ongoing Verification: Bedside Methods

While X-ray is the gold standard for initial placement, repeated X-rays are not practical for routine checks due to cost and radiation exposure. The most reliable bedside method for ongoing verification is pH testing of aspirated gastric contents.

pH Testing Procedure:
1. Attach a syringe to the feeding tube and gently withdraw a small amount of stomach contents (aspirate).
2. Place a few drops of the aspirate onto a pH indicator strip specifically marked for human aspirate.
3. Compare the color change on the strip to the pH chart provided on the container.
4. A pH reading of 5.5 or lower is generally considered safe for proceeding. A reading of 6 or higher suggests the tube may be in the lungs or intestines and should not be used.
5. Important considerations for pH testing include the patient's medication regimen, particularly acid-inhibiting medications, and the timing relative to feedings, both of which can alter gastric pH.
External Measurement: This method involves checking the external length of the tube to ensure the marking from the initial X-ray check has not moved from the insertion site. It is a secondary confirmation method that helps detect significant tube migration but does not guarantee the tip's exact location.

The Dangers of Unreliable Placement Methods

Outdated methods that are not evidence-based are still sometimes used, despite research proving their unreliability and associated risks.


Method	Description	Reliability	Reason for Unreliability	Recommended Use
Auscultation	Injecting air while listening for a "whoosh" sound over the stomach.	Unreliable	Sounds can be deceptively similar whether the tube is in the stomach, esophagus, or lungs.	No, abandon this method.
Visual Appearance	Checking the color of the aspirate (e.g., grassy green).	Unreliable	Respiratory and gastric fluids can have similar appearances, leading to misinterpretation.	No, use only in combination with pH testing.
Bubbling	Placing the end of the tube in water to check for bubbles.	Unreliable	Bubbling can occur when the tube is in the GI tract, and the absence of bubbles doesn't rule out respiratory placement.	No, abandon this method.
Clinical Signs	Relying on the absence of gagging or coughing.	Unreliable	Patients with decreased consciousness or compromised gag reflexes may not show distress, even with tracheal placement.	No, symptoms can be absent or misleading.
Radiography (X-ray)	Visual confirmation via imaging.	Highly Reliable	Considered the definitive 'gold standard' for verification.	Yes, for initial confirmation and when other methods are inconclusive.
pH Testing	Measuring the acidity of stomach aspirate.	Reliable (for ongoing checks)	Provides a quantitative measure of acidity, though can be affected by medication or feeds.	Yes, for routine bedside confirmation, with clinical awareness.

Conclusion: Prioritizing Safety Through Protocol

Correctly verifying tube placement is a crucial, non-negotiable aspect of medical care for preventing serious, potentially fatal complications. Evidence-based guidelines consistently emphasize the use of X-ray for initial placement confirmation, with subsequent routine checks relying on the combination of reliable bedside methods like pH testing and external tube measurement. Unreliable techniques such as auscultation have been widely condemned by patient safety organizations and must be discontinued. Adherence to these established protocols and continuous monitoring of the patient's condition are paramount for ensuring safe and effective treatment. Always consult and follow your local institutional guidelines and seek medical advice when in doubt about a tube's position.

Frequently Asked Questions (FAQs)

Frequently Asked Questions

The most reliable and recommended method for confirming initial tube placement is a chest X-ray.

For patients receiving continuous feeding, the American Association of Critical-Care Nurses recommends checking tube placement every four hours.

A gastric aspirate should typically have a pH of 5.5 or lower. If the reading is 6 or higher, placement should be reconfirmed by X-ray.

No, the 'whoosh test' (auscultation) has been proven to be unreliable and should not be used to verify tube placement.

If you cannot obtain an aspirate, do not use the tube. Take steps like repositioning the patient or injecting a small amount of air to clear the tip, but if still unsuccessful, assume misplacement and confirm with an X-ray.

Yes, displacement can occur from coughing, vomiting, or gagging. Tube placement should always be re-verified after such incidents.

Certain medications, especially acid-inhibiting drugs like proton pump inhibitors, can temporarily raise gastric pH, potentially making pH testing inconclusive.

If the tube's external measurement has changed since initial verification, it may have migrated. Do not use the tube and seek definitive radiographic confirmation.