Nasogastric Tube Insertion Guideline: How to insert and confirm an NG tube

Nasogastric Tube Insertion Guideline: How to insert and confirm an NG tube

How to put an ng tube

The nasogastric (NG) tube is a long polyurethane or silicone tube that is passed through the nasal passages via the esophagus into the stomach.

They are commonly inserted in surgical practice for various reasons.

It is important to take care to ensure that tubes placed are confirmed in order to prevent serious injury to the client.

Nasogastric tubes are inserted by nurses, junior doctors and sometimes by anesthetists in theatre.

It is vital that staff inserting them know the correct insertion technique as well as the procedure for verifying their correct positioning.

It is important to note that an NG tube insertion is not a sterile procedure but rather a clean one because the digestive tract is a contained system. Please check your hospital policy.

This article reviews the nasogastric tube insertion guidelines, nasogastric tube indications, and how to verify their correct intragastric positioning.

Reasons why an NG tube may be Inserted

There are only two main indications for NG tube insertion

  1. To empty the upper gastrointestinal tract or for feeding
  2. Insertion may be for prophylactic or therapeutic reasons such as medication administration and administration of contrast to the digestive tract.

These nasogastric tube indications are the main reasons for needing a tube.

Care should be taken in cases where there may be:

  • Risk of aspiration
  • Ear, nose and throat abnormalities or infections
  • Possible strictures (narrowing due to scars) of the esophagus
  • Esophageal varices
  • Anatomical abnormalities (esophageal diverticulae)

Nasogastric Tube Placement Contraindications

An NG tube insertion is should not be used when the patient has the following:

  • Recent facial surgery
  • coagulation disorder or abnormality
  • Esophageal varices
  • Esophageal bleeding or pressure
  • Sever facial trauma

Client’s chart should be verified for a provider’s order and reviewed for history of the above conditions prior to starting procedure.

Gaining Informed Consent for the NG Insertion Procedure

After reviewing client’s history and verifying the provider order for the type of tube and the feeding schedule (if for feeding). Practitioners should give patients a reassuring, detailed explanation of the insertion procedure, together with the reasons why the tube is necessary. Verbal consent should then be obtained.

Nasogastric Tube Sizes

Nasogastric tubes come in various sizes {8, 10, 12, 14, 16 and 18 fr (French gauge)}. Stiff tubes are easier to insert, and putting them in a refrigerator or filling them with saline helps to stiffen them. Some fine-bore tubes come with a guide wire to aid placement. The tube has markings and a radio-opaque marker at the tip to check its position on X-ray.


check ng tube placement

After educating the client about the procedure, you can perform the client vital signs before starting the procedure, this is known as the baseline vital signs.

Items you need for the procedure

  1. NG tube
  2. 60 ml catheter tip syringe
  3. Pulse oximeter
  4. Irrigation container
  5. Hypoallergenic tape
  6. Cup of water and straw
  7. Clean gloves
  8. Basin of water
  9. Soap
  10. Washcloth/towel
  11. Suction equipment
  12. Penlight
  13. Tongue blade
  14. Water-based lubricant
  15. Marker
  16. pH strip, as needed
  17. Oral hygiene supplies

Insertion Tube Insertion Technique

Tubes are usually inserted by nurses or junior doctors by the bedside or by anesthetists in theatre before or during surgery.

External measurement from the tip of the nose to the xiphoid process

The patient should sit up, this position is called a high fowlers position, without any head tilt (chin should be up). An appropriately sized tube is chosen and the tip is lubricated by smearing aqua gel or local anesthetic gel.

Anesthetic gel is a drug so if it is used it must be prescribed, and precautions taken such as checking for allergies.

The wider nostril is chosen and the tube slid down along the floor of the nasal cavity. Patients often gag when the tube reaches the pharynx. Asking them to swallow their saliva or a small amount of water may help to direct the tube into the esophagus.

Once in the esophagus, it may be easy to push it down into the stomach. Advance tube 25-30 cm. Stop and listen for air escaping tubing. Air present may indicate tube in trachea rather than esophagus

The tube is fixed to the nose and forehead using adhesive tapes. Mark the site with a marker.

The correct intragastric position is then verified. The stomach is decompressed by attaching a 60ml syringe and aspirating its contents. Blocked tubes can be flushed open with saline or air.

Nasogastric Tube Placement Confirmation

The intragastric position of the tube must be confirmed after its initial insertion, and this must be documented in the patient’s notes. The best way of confirming the tube’s position currently recommended is by conducting a Chest X-ray. Other methods can be inaccurate and should not be used as a method for confirming placement.


Chest X-ray: The Gold Standard of NG Placement Verification

It is best practice to use X-ray to check the tube’s location. Patients who have swallowing problems, confused patients and those in ICU should all be given an X-ray to verify the tube’s intragastric position.

This involves taking a chest X-ray including the upper half of the abdomen. The tip of the tube can be seen as a white radio-opaque line and should be below the diaphragm on the left side.


Other Methods of Verification of NG Placement

pH test

The NG tube is aspirated and the contents are checked using pH paper, not litmus paper.

You verify tube placement by aspirating stomach contents and checking pH.

  1. pH < or = 4 confirms gastric aspirate in adults
  2. pH < or = 5 confirms gastric aspirate in infants and young children
  3. Intestinal aspirate usually more yellow (stained by bile)
  4. Gastric aspirate not stained by bile.

Using the scale above you can see that it is safe to feed patients especially infants, children and adults if the pH is 5 or lower. This does not apply to neonate.

Please Note that taking proton pump inhibitors or H2 receptor antagonists may alter the pH. Similarly, intake of milk can neutralize the acid.

Syringe test

This test is mentioned here for historic interest only, also known as the whoosh test, it has been shown to be an unreliable method of checking tube placement and is no longer be used in most settings.

Correct intragastric positioning should be confirmed at all time

  • Immediately after initial placement
  • Before each feed
  • Following vomiting/coughing and after observing decreased oxygen saturation
  • If the tube is accidentally dislodged or the patient complains of discomfort

Never insert the guide wire while the nasogastric tube is in the patient

After the procedure

placing ng tube

Once the procedure is done, recheck the client’s vital signs and compare it with the baseline vitals.

Confirm the placement of the tubing by re-evaluating the x-ray. Be ready to routinely reassess the exit site marking on the tubing and also reassess the color and pH of the exudate from the tubing.

If you have any feedback, questions or concerns about this article. I would love to hear from you. Kindly leave your comments in the comments section below.

Thank you for reading!


Pam is the founder and author of InfoWatchNurse and ThinkStethoscopes. Pam is an award-winning leader. In 2017, She pioneered the first ever peer tutoring program for nursing students at York University. She was also a Peer Tutor and Mentor for nursing students. Today, Pam creates posts and articles on health topics to give back to the nursing community.  She blogs about nursing, health, nursing skills and other health related topics on her websites. You can connect with Pam on Linkedin and Instagram.

This Post Has 6 Comments

  1. Love this very educational I would’ve never thought this was how this work’s. As my gf wants to be in the medical industry we will definitely keep tabs on your site!

    1. Hi Jamaar

      Thank you for your comment, I am glad that you found this article informative. Have a great day



  2. Ouch, can they just knock me out and then insert the tube? I didn’t know this is how its done, I think I will learn a lot of medical stuff on your website.

    1. Hi Rose,

      It hurts a little at first but after a while it just feels a little uncomfortable and unfortunately you have to stay awake to help with insertion. For patients who are unconscious, there are several options for feeding tubes but the nasogastric tube is not usually a good idea. I hope you have a great day.



  3. Thanks for sharing the article. You are very detailed and I like that you shared a video to assist. I am not in the medical field so that really helped me to understand all the technical information you gave.

    Great article

    1. Thank you Ricia, I am glad that you enjoyed the post. Have a great day!



Leave a Reply

Close Menu