Nasogastric Tube (NG)
What is a nasogastric tube?
A nasogastric tube (NG tube) is a thin, flexible plastic tube that’s used for temporary medical purposes. “Nasogastric” means “nose to stomach”. The tube is designed to pass through your nasal cavity into your throat and down through your esophagus into your stomach. Healthcare providers use different types of nasogastric tubes to deliver substances to your stomach or draw substances out.
What is the purpose of a nasogastric tube?
Nasogastric tubes are used both to deliver substances to your stomach and to draw substances out. They’re often used for short-term tube feeding and to deliver oral medications to hospitalized people. They can also suction out stomach contents to relieve pressure or remove poisons.
The two primary purposes of the nasogastric tube are short-term tube feeding (and medication administration) and gastric suctioning (stomach pumping).
The NG tube can deliver special nutrition, as well as medication, directly to your stomach. You may need tube feeding (enteral nutrition) if you aren’t getting adequate nutrition from oral feeding. This may be the case if you have a condition that affects your appetite or makes it difficult to chew or swallow. Sometimes hospital patients just need additional nutrition to support their healing.
Some conditions that may require temporary tube feeding through a nasogastric tube include:
- Difficulty swallowing (dysphagia)
- Head and neck cancers.
- Altered mental status/unconsciousness.
- Inflammatory bowel disease (IBD).
- Endotracheal intubation.
Your healthcare provider may use a nasogastric tube to draw contents out of your stomach, either as a precaution or as an emergency procedure. If you swallow poison or overdose on pills, they will pump the toxic contents out. If a medical condition or procedure causes your stomach to become overfull and distended, they will draw out the contents to decompress your stomach and prevent regurgitation.
Some conditions that may require gastric suctioning through a nasogastric tube include:
- Toxic ingestion (poisoning).
- Gastroparesis or gastric outlet obstruction.
- Small bowel obstruction or pseudo-obstruction.
- Intractable nausea and vomiting.
- Upper GI bleeding.
- Gastrointestinal surgery.
What are the two types of nasogastric tubes?
The two main types correspond to the two main purposes of the nasogastric tube.
The single-lumen NG tube has a single, narrow channel for delivering medications and nutrition one way into your stomach. The channel has a small diameter (“small bore”) to make it as comfortable as possible, since it may be in place for up to several weeks. The Levin and the Dobhoff are the two main models in use. The main difference between them is that the Dobhoff tube has a weight on the end.
The double-lumen NG tube is specially designed for suctioning, but it can also be used for other purposes. It has two channels: a wider one to suction through and a narrower one that acts as an air vent to relieve the vacuum pressure. This helps prevent the tube from adhering to your stomach lining while suctioning. There are several models, but the Salem Sump™ may be the most common one.
What happens before a nasogastric tube is placed?
A trained healthcare provider will carefully prepare you before placing the tube. They will:
- Explain the procedure and ask for your signed consent.
- Place you in an upright sitting position, if possible.
- Put on medical gloves. (They don’t have to be sterile).
- Lubricate the first few inches of the tube with a sterile lubricating gel.
- Numb your sinus cavity and throat with an anesthetic such as lidocaine.
- Measure out in advance the correct length of tube that they will need to insert and mark it.
How do they measure the correct length of nasogastric tube to use?
Healthcare providers use different techniques to estimate the length of the tube they will need to reach your stomach (or sometimes, the upper part of your small intestine). The length is proportional to your body size, so they may measure it against other distances on your body. Or they may use general measurements: for example, 55 cm is the average length needed to reach the adult stomach.
What is the procedure for nasogastric tube insertion?
Your trained healthcare provider will:
- Insert the tube through one of your nostrils and aim it in a straight line toward the back of your throat. This is to avoid putting pressure on the roof of your sinus cavity.
- When the tube reaches the back of your throat, gently aim it down into your esophagus and slowly continue to advance it.
- Give you a cup of water with a straw to sip from, and ask you to take small sips and swallows. This will help pull the tube down through your esophagus. Alternatively, they may ask you to take a deep breath and hold it.
- Stop and withdraw the tube if you gasp, cough or show distress. They will try it again after a short break.
- Keep advancing the tube until it reaches the mark that indicates the correct length, then secure it with tape.
- Check to make sure the tube is in the correct place.
How do healthcare providers check the placement of the nasogastric tube?
Your provider must verify the correct placement of the nasogastric tube to prevent serious complications. They will do this using one of two tests:
- Chest X-ray. A chest X-ray is the most accurate way to check the placement of the NG tube, and experts recommend using it at least to check the initial placement. But it may not be possible or practical on a regular basis. Frequent exposure to X-ray radiation isn’t advised, and if you are going to need the tube for some time, you may be using it and checking it at home.
- Aspirate pH test. The next best way to check the placement of the tube is with an aspirate pH test. You or your provider will suction out a small amount of fluid and test it for acid content. If the tube is placed correctly in your stomach, the aspirated fluid should have stomach acid in it, which will give it a lower pH. This test is useful for quick checks during your intubation.
Is a nasogastric tube painful?
It can be a little uncomfortable, but hopefully not acutely painful. Healthcare providers can take certain steps to minimize your discomfort before, during and after insertion. For example:
- Give you an anesthetic lozenge to help numb your upper GI tract before installation.
- Administer anesthetic to your nose cavity and your throat.
- Lubricate the tube and use a gentle technique during insertion.
- Secure the tube well with tape so that it doesn’t move and cause friction.
- Gently clean and use topical skin treatments where the tube touches your skin.
- Look for signs of irritation at the site of insertion and switch nostrils if necessary.
How long can an NG tube stay in?
It’s only designed to be used for up to six weeks. If you end up needing enteral nutrition for longer than that, your healthcare provider will recommend switching to another kind of feeding tube. A gastrostomy or gastrojejunostomy tube feeds directly into your stomach or small intestine through a small incision in your abdomen. These tubes require minor surgery to install, but they’re safer for long-term use.
Risks / Benefits
What are the advantages of the nasogastric tube?
The NG tube doesn’t require surgery to install and can be installed quickly and safely in most people. This is especially helpful in an emergency, such as toxic ingestion, when you need to have your stomach pumped. It allows patients in diminished states of health to benefit from enteral nutrition without having to undergo surgery. It also provides helpful short-term uses, such as stomach decompression.
What are the complications or side effects of having a nasogastric tube?
If the tube is installed correctly, complications and side effects are relatively minor. They might include:
- Sinus infection.
- Sore throat.
- Pressure ulcers.
- Irritation to your stomach lining.
- The tube becoming entangled or dislodged.
- Electrolyte imbalances, such as hypokalemia (low potassium).
- Gastrointestinal bleeding from prolonged use.
These complications resolve when the tube is safely removed.
In the event of a bad installation, more serious complications could include:
When to Call the Doctor
When should I be concerned about my NG tube?
Alert your healthcare provider immediately if you notice:
- Any signs of infection, such as redness, swelling or fever.
- You choke, cough or vomit while the tube is in place.
- The tube becomes clogged or stops working.
- You accidentally dislodge the tube or it falls out.
- Any difficulty breathing.
- Blood in your tube or in your poop.
A note from Cleveland Clinic
A nasogastric tube may not be the most pleasant thing to have in your body, but it’s tolerable and has many important uses. It’s used preventatively during surgery, therapeutically for many conditions and sometimes as an emergency intervention. Most of us would prefer not to need one, but if you ever do, it might save your life. Or it might play an important role in a longer recovery process.
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