Explainers

How to Insert a Nasogastric Tube


Nasogastric (NG) tubes are a useful way to get access to the stomach, and insertion of them is an important skill for nurses to have under their belt. NG tubes intimidate many nurses because they are not often inserted, cause general discomfort to the patient, and may be difficult to insert in some cases. For this reason, it is important to go over the procedure for inserting an NG tube and to practise on patients whenever you can.

Preparation

You should gather all of your materials together before you approach the patient. There are two types of NG tubes: Levin and Salem sump. A Levin tube is often used for feeding, and it has lumens along the lower length. The Salem sump is used for suctioning because of the presence of a secondary tube, or pigtail, which allows for suctioning without adhering to the gastric wall. Depending on what you need or what the doctor has ordered, be sure to choose the correct tube for the job.
You will also need:

  • A towel
  • A glass of water with a straw
  • Water-based lubricant
  • An emesis basin; and
  • Personal protective equipment (gloves, gown, and face protection (including goggles)).

It is important to explain to the patient the process for inserting the NG tube, because it can be a scary and uncomfortable experience. Explain that they may experience gagging, choking and tearing eyes, but they need to swallow and follow directions closely to make the process as easy as possible.

You should also assess which nostril is the best one to use, particularly if the patient has a deviated septum, has had nasal surgery or has ever had their nose broken.

insert a nasogastric tube

Insertion

Before inserting the tube, you should measure the length of tube you will need. Take the end and measure from the nose to the earlobe, then from the earlobe to the xyphoid process. Mark this measurement with tape, and you can use this as a guide to help you know how far to insert the tube. Drape the patient with a towel and have them hold the glass of water and the straw. They should sit up as straight as possible and tilt their head back into a sniffing position. Lubricate the NG tube thoroughly to ensure the easiest insertion possible.

The Process

  1. Slowly insert the tube into the nare, curling down toward the back of the throat
  2. Once you reach the oropharynx, you may begin to encounter resistance. At this time, have the patient drop their chin to their chest
  3. As they take swallows of water through the straw, slowly advance the tube further. They may cough and gag at this point, but you should still be sure to encourage swallowing and incrementally advance the tube
  4. Once you are past the oropharynx, your patient should relax, and the tube will advance more easily
  5. Insert until you meet your tape mark and secure the tube

Note: you may encounter resistance and have to start again, perhaps using the other nostril. You can also look in the back of the throat to see if the tube has coiled there. Most nurses can insert an NG tube after a few attempts, but if you are meeting resistance, you should tell your supervisor or the physician that you are unable to advance the tube.

Evaluation

Evaluation of an NG tube is a tricky prospect and some controversy has arisen over what is proper evaluation of the placement. The gold standard for placement confirmation is an x-ray, but evaluation of aspirate from the tube is also viable. Stomach acid will look bright green while intestinal aspirate will be straw yellow. If you’ve managed to get inside the trachea, the discharge will be bright white. You can also test the pH of the aspirate with a testing strip. Stomach acid should be less than 5.6, while respiratory secretions are greater than 6.

Many have learned in nursing school to inject a bolus of air into the tube and listen over the stomach for a gurgling noise, but researchers now discount this method. If the tube were in the lungs, it would make a similar sound, and it is very difficult to tell the two apart. Most facilities require that x-ray confirmation be performed before using an NG tube. You should mark on the tube with a permanent marker where it enters the nose. This will help to determine if the tube has migrated and requires placement confirmation again, as it may have slipped into the respiratory tract.

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