Feeding tube

Overview
A feeding tube is a medical device used to provide nutrition to patients who cannot or refuse to (q.v. hunger strike) obtain nutrition by swallowing. The state of being fed by a feeding tube is called enteral feeding or tube feeding. Placement may be temporary for the treatment of acute conditions or lifelong in the case of chronic disabilities. Many patients treated using a feeding tube lack the ability to survive on their own without such technology.

A variety of feeding tubes are used in medical practice. They are usually made of polyurethane or silicone. The diameter of a feeding tube is measured in French units (each French unit equals 0.33 millimeters). They are classified by site of insertion and intended use.

Feeding tubes can be used for the force-feeding of prisoners on hunger strike, a controversial use. The World Medical Association prohibits the involuntary force-feeding of hunger strikers (except in cases of coma or mental impairment) through the Declaration of Tokyo (1975) and the Declaration on Hunger Strikers (1991). Feeding tubes are sometimes used on prisoners in a manner which can be categorized as torture, as allegedly at Guantanamo Bay detention camp (using nasogastric tubes). 

Feeding tubes are also used for the force-feeding of animals, such as the ducks and geese used to produce foie gras.

Nasogastric
A nasogastric feeding tube, or "NG-tube", is passed through the nares, down the esophagus and into the stomach.

Gastric feeding tube
A gastric feeding tube, or "G-tube", is a tube inserted through a small incision in the abdomen into the stomach and is used for long-term enteral nutrition. The most common type is the percutaneous endoscopic gastrostomy (PEG) tube. It is placed endoscopically: the patient is sedated, and an endoscope is passed through the mouth and esophagus into the stomach. The position of the endoscope can be visualized on the outside of the patient's abdomen because it contains a powerful light source. A needle is inserted through the abdomen, visualized within the stomach by the endoscope, and a suture passed through the needle is grasped by the endoscope and pulled up through the esophagus. The suture is then tied to the end PEG tube that will be external, and pulled back down through the esophagus, stomach, and out through abdominal wall. The insertion takes about 20 minutes. The tube is kept within the stomach either by a balloon on its tip (which can be deflated) or by a retention dome which is wider than the tract of the tube.

Gastrostomy tubes can also be placed in "open" procedures through an incision with direct visualization of the stomach, as well as via laparoscope. Gastric tubes are suitable for long-term use: they last about six months, and can be replaced through an existing passage without an additional endoscopic procedure. The G-tube is useful where there is difficulty with swallowing because of neurologic or anatomic disorders (stroke, esophageal atresia, tracheoesophageal fistula), and to avoid the risk of aspiration pneumonia. It is also used when patients are malnourished and cannot take enough food by mouth to maintain their weight. They also can be used in "reverse" to drain stomach contents.

Jejunostomy tube
A jejunostomy tube is similar to a gastric tube, though generally has a finer bore and smaller diameter, and is surgically inserted into the jejunum rather than the stomach. They are used when the upper gastrointestinal tract must be bypassed completely, and can be used as soon as 12 hours after surgery. This type of tube is usually used for people who are at high risk for aspiration.

These small bore tubes are prone to clogging, particularly with some medications and if not flushed as directed. Feeding through these tubes are generally commercially prepared to provide adequate nutrition and to not result in clogging when used with a pump or with drip feedings.

Gastrojejunostomy tube
Dual-lumen feeding tubes are available. Typically, the gastric lumen is used for decompression. The jejunal lumen is used to administer feedings. Either a percutaneous or open technique can be used. The jejunal portion of the tube can occasionally migrate back into the stomach, often requiring endoscopic repositioning.

Effectiveness
Nutritional supplementation is not necessary if the patient is not eating for four days or less and maybe also if duration is seven days or less.

A randomized controlled trial found no difference between the NG tube and PEG tube in stroke patients.

Complications
Damage to nearby structures, most commonly the colon, can occur with percutaneous techniques. Dislodgement of the tube can occur, leading to peritonitis in certain circumstances. Feeding tubes can become occluded or inadvertently pulled out. The tube can migrate distally and obstruct the pylorus, leading to gastric outlet obstruction. Abdominal fascial dehiscence can occur with an open technique. After removal of the feeding tube, a gastrocutaneous fistula can result if the tract does not close.

Withdrawal
Tube feeding, like all medical treatments, can be declined or withdrawn, especially in the setting of a terminal illness where its use would not alter the ultimate outcome. Actively withdrawing an existing feeding tube is considered by some to be a form of active euthanasia, while deciding not to place one could be considered passive euthanasia.