Nasogastric intubation

Nasogastric intubation is a medical process involving the insertion of a plastic tube (nasogastric tube, NG tube) through the nose, past the throat, and down into the stomach.

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Technique

Before an NG tube is inserted, the Health Care Provider - most often the nurse, must measure with the tube from the tip of the patient's nose, to their ear and down to the xyphoid process. Then the tube is marked at this level to ensure that the tube has been inserted far enough into the patient's stomach. The end of a plastic tube is lubricated and inserted into one of the patient's anterior nares. It is then moved through the nasal cavity and down into the throat. Once the tube is past the pharynx, it is rapidly inserted down into the stomach.

During the tube's insertion, the patient may gag; in this situation the patient is given water to drink, and the tube continues to be inserted as the patient swallows. Great care must be taken to ensure that it has not passed through the windpipe and down into the lungs. To ensure proper placement it is recommended (though not unequivocally confirmed) that injection of air into the tube be performed,^[1] if the air is heard in the stomach with a stethoscope, then the tube is in the correct position. Another method is to aspirate fluid from the tube with a syringe. This fluid is then tested with pH paper (note not litmus paper) to determine the acidity of the fluid. If the pH is 5.5 or below then the tube is in the correct position. If this is not possible then correct verification of tube position is obtained with an X-ray of the chest/abdomen.^[2] If the tube is to remain in place then a tube position check is recommended before each feed and at least once per day.

Uses

The main use of a nasogastric tube is for feeding and for administrating drugs and other oral agents (such as activated charcoal and radiographic contrast material). For drugs and for minimal quantities of liquid, a syringe is used for injection into the tube. For continuous feeding, a gravity based system is employed, with the solution placed higher than the patient's stomach. If accrued supervision is required for the feeding, the tube is often connected to an electronic pump which can control and measure the patient's intake and signal any interruption in the feeding.

Treatment for severe anorexia can include nasogastric feeding to stabilize body weight.

Nasogastric aspiration (suction) is the process of draining the stomach's contents via the tube. Nasogastric aspiration is mainly used to remove gastric secretions and swallowed air in patients with gastrointestinal obstructions. Nasogastric aspiration can also be used in poisoning situations when a potentially toxic liquid has been ingested, for preparation before surgery under anesthesia, and to extract samples of gastric liquid for analysis.

If the tube is to be used for continuous drainage, it is usually appended to a collector bag placed below the level of the patient's stomach; gravity empties the stomach's contents. It can also be appended to a suction system, however this method is often restricted to emergency situations, as the constant suction can easily damage the stomach's lining.

It has also been used in Guantanamo Bay detention camp to force feed prisoners.[1]

Contraindications

Nasogastric intubation is contraindicated (inadvisable) in patients with facial trauma, base of skull fracture, esophageal abnormalities, and altered mental status or an impaired airway.

Complications

Minor complications include nose bleeds, sinusitis, and a sore throat. Sometimes more significant complications occur including erosion of the nose where the tube is anchored, esophageal perforation, pulmonary aspiration, a collapsed lung, or intracranial placement of the tube.

References