What type of X-ray should be ordered to confirm nasogastric tube (NGT) placement?

Radiographic Confirmation of Nasogastric Tube Placement

Every patient with a nasogastric tube should undergo radiography to confirm proper position before feeding is initiated. 1

Why X-ray Confirmation is Essential

Proper confirmation of nasogastric tube (NGT) placement is critical for patient safety. While bedside methods like auscultation are commonly used, they can be dangerously misleading:

• Auscultation can misinterpret tubes positioned in the lung, pleural cavity, or coiled in the esophagus as being correctly placed 1
• Misplaced tubes can lead to serious complications including aspiration pneumonia, pneumothorax, and even death
• Between 2005 and 2010,45% of all cases of harm caused by misplaced NGTs reported by the National Patient Safety Agency were due to misinterpreted radiographs 1

Type of X-ray Recommended

The recommended radiographic study for confirming NGT placement is:

• Plain chest X-ray (anteroposterior view) that includes visualization of the upper abdomen 1
• This allows visualization of the entire course of the tube from insertion through the esophagus and into the stomach

When X-ray Confirmation is Required

X-ray confirmation is necessary:

• After initial blind placement of any NGT before feeding is initiated 1
• When there is clinical suspicion of tube displacement
• After episodes of vomiting, retching or coughing that might displace the tube
• Before resuming feeding after a patient has been prone (particularly relevant in COVID-19 patients) 2

Alternative Confirmation Methods

While chest X-ray remains the gold standard, several alternative methods have emerged:

1. Ultrasonography:

   • Can visualize the NGT in the stomach in up to 76.8% of cases 2
   • Shows characteristic "whoosh" or "flash" when air is instilled through the tube 2, 3
   • Sensitivity of 98.9% compared to X-ray in COVID-19 patients 2
   • Particularly useful when frequent repositioning (like proning) requires repeated confirmation 2

2. Electromagnetic guidance devices:

   • High sensitivity (98%) and specificity (100%) compared to X-ray 4
   • Can detect lung placements immediately, avoiding potential complications 4
   • Reduces time to feeding initiation (average 404 minutes with X-ray confirmation) 4

Pitfalls and Caveats

• X-ray interpretation errors: Radiographs must be carefully interpreted by trained personnel, as misinterpretation is common 5
• Tube migration: A correctly placed tube can migrate after initial confirmation, particularly with patient movement or procedures
• Incomplete visualization: Ensure the X-ray captures both the course and tip of the NGT
• pH testing: While useful as an adjunct, pH testing alone is not sufficient to confirm initial placement 6
• Water-soluble contrast: In cases where the tube position remains uncertain on plain film, administration of water-soluble contrast through the NGT can help confirm position 1

Algorithm for NGT Placement Confirmation

1. Place NGT using appropriate technique
2. Obtain chest X-ray that includes upper abdomen
3. Confirm tube follows expected anatomical course
4. Verify tube tip is in the stomach (not in esophagus, lung, or pleural space)
5. Document confirmation before initiating feeding
6. Consider alternative confirmation methods (ultrasound, electromagnetic guidance) in settings requiring frequent repositioning or confirmation

By following this evidence-based approach to NGT placement confirmation, clinicians can significantly reduce the risk of complications associated with misplaced feeding tubes.