A nasogastric tube or an NG tube is a long, thin tube made of polyurethane, silicone, or rubber. It is inserted into a patient’s nasal or oral passage to administer or remove substances in the stomach. Comatose patients and patients with trauma to their oral pathway also use nasogastric tubes.
How long can you keep a nasogastric tube?
The NG tube is a temporary solution and usually used less than 6 weeks. Then, it is either removed or replaced by something more permanent. The nurse or doctor inserts an NG tube. After insertion, an x-ray confirms the placement.
Sizes of NG tubes
These tubes come in varying sizes, from 4 to 18 French. The French scale or French gauge system is commonly used to measure the size of a catheter. 1 “French” or “Fr” is equivalent to 0.33 mm.
How to select a nasogastric tube size?
Each age group uses a different sized NG tube. For example, neonates typically use 4 to 8 Fr, pediatric patients use 6 to 14 Fr, 21.5 to 39″ long and adults use 12 to 18 Fr, with a length of 42 to 50″.
Uses/indications for a nasogastric tube
Apart from the purposes as mentioned earlier, other indications for the use of NG tubes are:
- medication administration
- gastric decompression
- aspiration of ingested toxic materials
- bowel rest with a small bowel obstruction
- traumatic injuries (such as gunshot wounds)
- mechanical ventilation
- paralytic ileus
- metastatic gastric diseases
- failed to swallow study/high risk of aspiration.
If the patient requires extra calories and cannot eat, the NG tube serves feeding purposes (enteral feeding via an NG tube). An ordered specialized formula is fed to the patient via the NG tube. However, all formulas have the same necessary ingredients: water, carbohydrates, fat, protein, vitamins, and minerals.
Types of nasogastric tubes
Types of nasogastric tubes include
1. Levin catheter
what is levin catheter?
single lumen, small-bore NG tube. It serves to administer medication or nutrition, and it bears permanent markers 18″, 22″, and 30″ from the distal tip to help with the proper placement.
Polypropylene is the most typical material making the Levin catheter. Polypropylene tubes bed less compared to others and are more capable of creating a false passage during a placement.
what are the advantages and disadvantages of a levin catheter?
One advantage of the Levin tube is that it has a relatively larger internal diameter compared to its external diameter. On the other hand, a Levin tube should be unhooked from the suction after the contents of the stomach drain out. This is because the suction will cause the stomach to invaginate and block tube function, leading to injury of the stomach lining.
Levin tubes are not the choice of NG tube in cases of emergency.
2. Salem Sump catheter
what is Salem sump catheter?
a large bore NG tube with a double lumen. Used for aspiration in one lumen, and venting in the other.
Most commonly made out of Polypropylene, the Salem Sump catheter is too rigid for long-term use as a feeding tube. It is less prone to kink than others but can create a false passage during placement.
What are the advantages and disadvantages of a Salem sump catheter?
Latex/rubber tubes are moderately firm and thickly walled. They require more lubrication for passage. It can induce a foreign body reaction more than tubes made of other common materials. Latex also deteriorates rapidly compared to other materials.
The Salem sump tube triumphs the Levin tube for chronic uses (as a drainage device). This is because it has a separate (blue-colored) channel venting the distal central lumen to the atmosphere. This vent prevents excessive vacuum formation.
How to use the Salem sump catheter?
When using a Salem sump, keep the blue pigtail is above the level of the fluid in the patient’s stomach. If not, the stomach contents can backflow through the vent lumen. When ambulating, the blue pigtail fits into the plastic connector at the end of the suction lumen. A leak-free, closed-loop is created.
3. Dobhoff tube
What is Dobhoff tube?
it is a small-bore NG tube with a weight at the end to pull it by gravity during insertion. Dobhoff tube is flexible and, thus, more comfortable to the patient than other tubes.
How Dobhoff tube is inserted?
A guidewire called the stylet is handy when inserting the tube. After confirming correct tube placement, removal of the stylet takes place. It has a diameter of 4 mm, which makes it comfortable for the patients.
What are the uses of a Dobhoff tube?
The tube delivers enteral nutrition in patients with a functional gastrointestinal tract but unable to meet their nutritional needs via oral intake. It also drains the digestive tract. But a Dobhoff tube cannot take suctioning. Thus, it is of limited use to enteral feeding and medication delivery.
what are the Risks of using Dobhoff tube?
The metal stylet can cause the tube to enter into the airway, especially if the patient has an altered gag or cough reflex. If the tube is in the lung, the metal stylet can cause tracheo-pulmonary complications such as pneumothorax.
Therefore, the benefit of using a specific nasogastric tube should outweigh the risks it poses.