Why Is Checking Feeding Tube Placement Critical?
Administering feedings or medications into a tube that is not correctly positioned in the stomach can lead to serious, life-threatening complications, most notably aspiration pneumonia. Incorrect tube placement can cause fluids or food to enter the patient's lungs, leading to severe respiratory distress. For this reason, verification of correct placement is not a suggestion—it is a critical nursing responsibility that must be performed consistently and accurately. Checking the tube's position prevents serious injury or death and ensures the patient receives proper nutrition and medication.
Reliable Methods for Checking Placement
pH Testing of Gastric Aspirate
pH testing is a common and reliable method at the bedside for confirming NG tube placement in the stomach. The procedure involves gathering equipment, positioning the patient, aspirating gastric contents, and testing the pH of the aspirate. A pH reading between 1 and 5 typically indicates stomach placement, while a reading over 6 suggests potential misplacement.
External Tube Length Measurement
Measuring the external length is a bedside check to ensure the tube hasn't moved after initial X-ray confirmation. After initial confirmation, mark and document the tube length at the exit site. Check this length regularly and before each use; significant changes may indicate migration.
Radiographic Confirmation (X-Ray)
An X-ray is considered the most definitive method, or "gold standard," for confirming tube placement, particularly after initial insertion or when placement is uncertain. It provides a visual confirmation of the tube's location.
Unreliable and Unsafe Methods
Using unreliable methods to check tube placement can lead to serious, even fatal, consequences like undetected misplacement.
The Auscultation or "Whoosh" Test
Injecting air into the tube and listening for a sound over the abdomen (the "whoosh" test) is unreliable and lacks specificity. It should never be used.
Observing the Appearance of the Aspirate
The color and appearance of aspirated fluid alone are not definitive and relying solely on visual inspection is unsafe. Gastric aspirate can vary in appearance, and feeding formulas can obscure accurate assessment.
Comparison of Feeding Tube Placement Verification Methods
| Method | Reliability | Procedure | Pros | Cons |
|---|---|---|---|---|
| pH Testing | High (Bedside) | Aspirate fluid, test with pH paper. | Quick, simple, reliable bedside method for routine checks. | Can be altered by feeding formula or certain medications; sometimes hard to obtain an aspirate. |
| External Length | Moderate (Bedside) | Measure visible tube length against documentation. | Easy and quick; helps detect tube migration. | Not a reliable initial placement check; doesn't confirm location, only movement. |
| X-Ray (Radiography) | Highest (Initial) | Obtain and interpret a chest/abdominal X-ray. | Gold standard for initial placement confirmation. | Radiation exposure, cost, delays in feeding, and interpretation errors are possible. |
| Auscultation ("Whoosh" Test) | Very Low (Unsafe) | Inject air and listen for a sound with a stethoscope. | None; should not be performed. | Extremely unreliable and dangerous; can result in fatal aspiration. |
Conclusion
Confirming correct feeding tube placement is essential for safe patient care. While X-ray is the standard for initial checks, bedside methods like pH testing and external length measurement are vital for routine verification. Healthcare providers must use only evidence-based techniques and avoid unreliable methods like the "whoosh" test, which pose significant risks. Following established protocols ensures patient safety before using a feeding tube. For additional information on best practices, consult medical guidelines from authoritative sources, such as the National Institutes of Health.
National Institutes of Health (NIH) - Chapter 17 Enteral Tube Management
