From the Guidelines
An NG tube is considered successfully placed and safe to use on X-ray when the tube is visualized passing through the esophagus and into the stomach, with the tip positioned below the gastroesophageal junction and above the pylorus, as confirmed by radiographs, which are the gold standard for nasogastric tube placement confirmation 1. This confirmation is crucial to prevent serious complications, including pneumonia, pneumothorax, or even death, which can occur if the tube is misplaced into the lungs.
Key Considerations for NG Tube Placement
- The tube should follow the expected anatomical course down the midline of the chest and curve into the stomach, without any coiling in the esophagus or extension into the lungs or bronchi.
- Proper placement is confirmed when the tube is seen crossing the diaphragm and the tip is visible within the gastric air bubble.
- The tube should not appear doubled back on itself or positioned in the intestines unless that was the intended placement (as with longer feeding tubes). While bedside tests like air insufflation and pH testing can provide initial assessment, X-ray verification remains the gold standard for confirming proper placement before first use of the tube 1.
Importance of X-ray Verification
- X-ray verification is essential to ensure the tube is correctly placed, reducing the risk of complications.
- Misplacement into the lungs can cause serious complications, including pneumonia, pneumothorax, or even death 1.
- Radiographic confirmation is necessary before initiating feeding or medication administration through the tube.
From the Research
Nasogastric Tube Placement Confirmation
To determine when an NG tube is placed successfully and safe to use on an X-ray, several methods can be considered:
- pH testing of nasogastric aspirates to confirm ongoing NGT position, as recommended by the NHS 2
- Radiography to confirm correct placement of the NGT, especially when pH testing is inconclusive 3
- External NGT length measurement to identify misplaced NGTs 4
pH Testing Reliability
The reliability of pH testing to confirm NGT position has been questioned:
- A study found that ongoing pH tests had minimal reliability (Cohen's Kappa = 0.29) in confirming NGT position 2
- Another study found that pH testing was reliable when the pH was 4 or lower, but radiography may be necessary when the pH is higher than 4 3
- A systematic literature review found that ongoing pH testing is based on expert opinion due to limited evidence 4
Alternative Methods
Other methods, such as capnography and capnometry, have been explored to confirm NGT placement:
- A study discussed the theory-practice gap and preliminary research behind these techniques 5
- A review article discussed evidence-based methods for assessing tube placement, including the limitations of each method 6
X-ray Confirmation
X-rays can be used to confirm NGT placement: