Nasogastric/Orogastric (NG/OG) Tube Insertion – Technique and Overview

Name of Procedure

Nasogastric (NG) or orogastric (OG) tube insertion

Goal

To insert a tube into the stomach.

Indications

Almost any situation where you want access to the stomach or it’s contents:

  • Aspiration
    • Gastric decompression (for GI motility, bowel obstruction)
    • Ensuring an empty stomach to prevent aspiration
    • Gastric content sampling
    • Emptying during drug overdose
    • Evaluate for GI bleeds
  • Administration
    • Nutritional support
    • Delivery of medications

Contraindications

  • Local facial or esophageal trauma (including cribriform plate disruption if considering an NG tube specifically)
  • Recent nasal surgery
  • Recent alkaline ingestion
  • Esophageal varices (untreated or recently banded/cauterized)
  • Esophageal strictures

Anatomy

NG (nasogastric) [green] and OG (orogastric) [purple] tube path

The key points to remember about anatomy:

  1. The path from the nostril to the back of the nasopharynx is straight posterior. So when inserting an NG tube you direct the tube straight posteriorly.
    1. The orientation of the nostrils might lead you to aim superiorly, which is not correct
  2. From the mouth or nose, the path will take a 90 degree turn inferiorly near the pharynx.
  3. The patient may have one nostril that is more patent and is a better path. Having the patient breach through each side can help you determine which side might be better.
  4. The esophagus sits posterior to the trachea but the tube can sometimes redirect into the trachea/bronchi/lungs.

Equipment/Skills/Setup

  1. Suction
  2. NG/OG tube
  3. Water soluble lubrication 
  4. Possibly topical anesthetic 

Landmarks and Patient Positioning

This will depend on the context of the situation (such as OR, ICU, etc), but often the patient should be lying supine with the neck in a neutral or flexed position. The patient may also be awake and sitting up slightly

Technique

We will assume an anesthetized patient and NG placement. Setup:

  1. Make sure suction is active and readily available to grab since you want to be able to use it quickly if the patient starts gagging/vomiting, which could quickly lead to aspiration.
  2. Visualize the tube on the outside of the body (from the nostril to about the stomach) to get a rough idea of how much tube that you’ll need to advance.
  3. Apply a small amount (1-2mL) of lubricant near the tip of the tube.

Start your procedure:

  1. Insert the tube into the nostril aiming straight posteriorly (towards the back of the head, not the top of the head).
  2. The tube may have a slight bend to it. Keep track of the orientation of your bend.
  3. Near the posterior nasopharynx you might feel mild resistance as the tube needs to bend to aim inferiorly to the esophagus. Orientating the bend in that direction can help.
  4. Continue to advance. Slight turning of the tube (or withdrawing and advancing) might be occasionally necessary to get past points of resistance.
    1. There shouldn’t ever be a lot of resistance. This might indicate it’s up against tissue/other structures and excessive pushing can cause damage.
  5. Once you’ve advanced roughly the right amount and you hit resistance you’re probably in the stomach.
  6. Attach suction or a large syringe to see if you get gastric contents, which you may or may not get.
  7. Confirm placement with several options:
    1. Obvious return of gastric contents
    2. Look for ventilation changes
      1. Leaking air/pressure during ventilation through the ETT might suggest the NG tube is sitting next to the ETT and letting air escape.
    3. Xray to confirm tube in the stomach (or incorrect placement by seeing the tube leave midline and follow the path of a bronchus)
  8. Secure the NG tube if necessary
    1. Ensure that the tube isn’t compressing any soft tissue (e.g., part of the lip between the tube and teeth). Then tape it down.

Tips

  1. Awake patient
    1. Placement in an awake patient requires some additional considerations and coaching of the patient.
    2. See references below for some instructions and tips specific to this scenario.
  2. In an intubated patient the endotracheal tube in the trachea might help redirect the gastric tube down the esophagus
    1. Also, if the tube does enter the trachea, then the inflated cuff might stop it from being advanced.

References