Intubation of the digestive tract is the process of passing a small, flexible plastic tube (nasogastric tube) through the nose or mouth into the stomach or small intestine. This procedure may be used for diagnostic or treatment purposes. Intubation typically causes gagging and nausea, so a numbing agent may be sprayed in the nose and back of the throat. The tube size varies according to the purpose.
Nasogastric intubation can be used to obtain a sample of stomach fluid. The tube is passed through the nose rather than through the mouth, primarily because the tube can be more easily guided to the esophagus. Also, passage of a tube through the nose is less irritating and less likely to trigger coughing. Doctors can determine whether the stomach contains blood, or they can analyze the stomach’s secretions for acidity, enzymes, and other characteristics. In people with poisoning, samples of the stomach fluid can be analyzed to identify the poison. In some cases, the tube is left in place so that samples can be taken over several hours.
Nasogastric intubation may also be used to treat certain conditions. For example, poisons can be pumped out or neutralized with activated charcoal, or liquid food can be given to people who cannot swallow.
Sometimes nasogastric intubation is used to continuously remove the contents of the stomach. The end of the tube is usually attached to a suction device, which removes gas and fluid from the stomach. This helps relieve pressure when the digestive system is blocked or otherwise not functioning properly. This type of tube is often used after abdominal surgery until the digestive system can resume its normal function.
In nasoenteric intubation, a longer tube is passed through the nose, through the stomach, and into the small intestine. This procedure can be used to remove a sample of intestinal contents, continuously remove fluids, or provide food (see Tube feeding).
Complications resulting from nasogastric intubation are relatively rare and include injury to the nose, throat, or digestive tract. They very rarely cause perforations.