This is a UKMLA-centred article about nasogastric tube insertion.

Introduction

A nasogastric tube, also known as a NG tube is a common medical procedure employed in various healthcare settings. This guide will cover the indications for the insertion of a NG tube, contraindications and potential complications and the equipment and methods required for successful insertion.

Indications

A NG tube is a flexible tube inserted through the nostril, down the throat, and into the stomach. It serves a vital role in providing enteral nutrition, delivering medications, decompressing the stomach and diagnostic purposes.

• Enteral nutrition: patients who are malnourished or at risk of malnutrition who have inadequate or contraindicated oral intake and a functional gastrointestinal tract may require feeding through a NG tube. Examples of situations include patients with neurological conditions causing dysphagia e.g. stroke, lowered consciousness level e.g. coma or following upper gastrointestinal surgery where a high anastomosis must be protected initially in the post-operative period.
• Medication administration: some medications are better absorbed in the stomach, making NG tubes a preferred route when oral administration is not possible
• Gastric decompression: to relieve gastric distension caused by conditions like bowel obstruction or ileus, or alternatively, aspiration of ingested toxic material. This involves removing gastric contents as opposed to passing substances into the gastrointestinal system.
• Diagnostic uses: on occasion, NG tubes can be used to aspirate gastric contents for analysis, aiding in the diagnosis and management of gastrointestinal bleeding.

Contraindications

The following are some contraindications to NG tube insertion, although this is not an exhaustive list:

1. Basal skull fractures
2. Unstable cervical spine injuries
3. Nasal/oesophageal obstruction or ulceration
4. Oesophageal pouch/stricture/tumours/surgery
5. Clotting disorder
6. Actively bleeding oesophageal or gastric varices

Complications and Risks

Varying levels of expertise in placing NG tubes should be taken into consideration and advice should be sought if there is any uncertainty regarding insertion. NG tubes should never be forced if resistance is felt. A maximum of 3 attempts should be made at one time, after which senior specialist advice should be sought.

Potential complications which may arise during insertion include:

• Misplacement
• Nasal and oesophageal trauma
• Aspiration
• Infection
• Dislodgement

Types

Single lumen

• has a single, narrow channel for delivering medications and nutrition one way into your stomach. The Levin and Dobhoff are the two main models in use.

Double lumen

• has two channels, a wider one for suctioning and a narrower one that acts as an air vent to relieve the vacuum pressure. There are several models, but the Salem Sump is the most common.

Procedure

Equipment:

• Clean tray
• Disposable gloves
• Apron
• Nasogastric tube
• pH indicator strips (CE marked)
• Nasal dressing to secure tube
• 60ml oral/enteral syringe (with purple barrel)
• Sterile water
• Tissues
• Lubricant
• Disposable sick bowl
• Cup of waterwith straw (if patient has safe swallow and not nil by mouth)

Checking Placement

Once the NG tube is inserted, it is important to ensure it has been placed in the correct location. The first-line method used is pH testing using CE marked pH indicator paper which has been manufactured to test human gastric aspirate. X-ray is used only as a second line test when no aspirate is obtained or the pH indicator has failed to confirm the position.

To conduct pH testing, attach the enteral syringe to the connector on NG tube, pull back plunger to aspirate fluid. Once aspirate is obtained, remove syringe and apply aspirate onto the pH indicator strip, covering all three coloured squares.

If the pH is 5 or less this is good and indicates the NG tube is in the stomach and is safe to be used.

NOTE: gastric pH levels may be elevated above 5 as a result of medication e.g. H2 antagonists/PPIs/antacids.

Conclusion

Once you are confident that the NG tube has been inserted correctly and carried out all checks, confirmation should be fully documented in the Nasogastric Feeding Tube Care Plan.

Positioning of a NG tube should be carried out in accordance with local trust guidelines, as equipment and procedure may differ slightly.

Removal and replacement of NG tubes should be carried out after discussion with seniors and dieticians, for review of nutritional status. The timeline of when to replace a NG tube differs regarding the tube type, again checking with local guidelines.

Trained medical staff are able to insert a NG tube, taking into account possible contraindications and complications. A multidisciplinary approach and thorough documentation are vital to ensure safe practice.

References
 
1. https://www.gla.ac.uk/media/Media_678213_smxx.pdf

2. https://my.clevelandclinic.org/health/treatments/24313-nasogastric-tube


3. Thumbnail image credit: Cancer Research UK / Wikimedia Commons

Author – Mohona Sengupta  

Editor – James Mackintosh

Last updated 18/12/23