What is the common depth for nasogastric (NG) tube insertion in adults?

Common Depth for Nasogastric Tube Insertion in Adults

The recommended depth for nasogastric tube insertion in adults is approximately 50-60 cm, measured from the xiphisternum to the nose via the earlobe. 1

Measurement Methods for Determining NG Tube Length

Recommended Measurement Techniques

The traditional nose-ear-xiphoid (NEX) method has been shown to be inadequate, with research demonstrating it frequently results in improper positioning:

• Most accurate method: The xiphisternum-to-ear-to-nose + 10 cm method has been shown to provide the best estimate for proper NG tube placement, with an average difference of only 1.8 cm from optimal positioning 2

• Alternative effective methods:

  • (NEX × 0.38696) + 30.37 + 6 cm (accuracy up to 99.0%) 3
  • NEX + 10 cm (accuracy up to 97.4%) 3
  • [(NEX-50 cm)/2] + 50 cm 4
  • Gender-weight and nose-umbilicus-flat method 4

Methods to Avoid

• The traditional NEX method alone is inadequate and should not be used, as it results in tubes that are too short, with 96.7% of placements failing to correctly position all side holes in the stomach 5

Proper Insertion Technique

1. Explain the procedure to the patient
2. Mark the tube at the predetermined distance (50-60 cm for most adults)
3. Lubricate the tube externally with gel/water and internally with water if using a guidewire
4. Check nasal patency by having the patient breathe through each nostril separately
5. Position the patient upright with head level
6. Insert the tube gently along the floor of the clearer nostril until visible at the back of the pharynx (10-15 cm)
7. Advance the tube 5-10 cm as the patient swallows water (if cooperative)
8. Continue advancing until the preset mark reaches the nostril
9. Remove any guidewire and secure the tube carefully
10. Verify tube position before use 1

Verification of Tube Placement

• Always confirm proper NG tube position before each feeding using pH testing
• For initial placement, radiographic confirmation may be necessary to ensure the tube is properly positioned in the stomach
• Monitor for signs of improper placement such as coughing, cyanosis, or respiratory distress 6

Common Pitfalls and Complications

• Underinsertion: Any side hole above the gastroesophageal junction increases risk of aspiration and pneumonia
• Overinsertion: May cause the tube to kink in the stomach, curl upward into the esophagus, or enter the duodenum 7
• Improper fixation: 40-80% of NG tubes become dislodged when not properly secured 6
• Prolonged use: Increases risk of sinusitis, aspiration pneumonia, and patient discomfort 6

Special Considerations

• For patients requiring long-term enteral feeding (>4-6 weeks), consider gastrostomy or jejunostomy placement 1, 6
• For patients with gastric reflux or delayed gastric emptying, consider nasojejunal tube placement 1
• Position patients at 30° or higher during and for 30 minutes after feeding to reduce aspiration risk 6
• Monitor gastric residual volumes before each feeding, considering delay if residual exceeds 150ml 6

By following these guidelines for proper measurement, insertion, and verification of NG tube placement, clinicians can minimize complications and ensure optimal patient outcomes.