As a nurse, very few procedures are as intimidating as inserting your first nasogastric (NG) tube. However, it doesn't have to be. Knowing what you need to do and what to look for in your patients will not only reduce your anxiety, but also improve your patients' prognosis and help them reach their maximum health potential.
What's the deal?
An NG tube is a long, thin polyurethane, silicone, or rubber tube that's inserted into a patient's nasal or oral passage to administer (gavage) or remove (lavage) substances in the stomach. NG tubes come in sizes ranging from 4 French (Fr) to 18 Fr. (For sizes measured in Fr: the smaller the number, the smaller the diameter.) The sizes are further broken down by age groups. Neonatal patients typically use 4 to 8 Fr; pediatrics, 6 to 14 Fr, with a length of 21.5 to 39 in; and adults, 12 to 18 Fr, with a length of 42 to 50 in.
NG tubes are often used for patients who are comatose or have experienced trauma to their oral pathway. Other indications include:
* hydration
* nutrition
* 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 swallowing study/high risk of aspiration.
The NG tube is typically a temporary solution-usually less than 6 weeks-and may later be removed or replaced by a more permanent apparatus. NG tube insertion is generally performed by the RN or the physician. After insertion, placement is confirmed by X-ray.
If your patient needs extra calories and is unable to eat, the NG tube may also be used for feeding. The specific type of formula is ordered by the physician: modular, polymeric, elemental, and specialized formulas are available. Although all formulas have the same basic ingredients/components-water, carbohydrates, fat, protein, and vitamins and minerals-each formula is different. There are formulas that enhance wound healing, others help control blood glucose, some optimize the respiratory system, and still others work with the kidneys. However, most formulas provide 100% of the daily recommended amounts of vitamins and minerals. Elemental formulas don't contain whole proteins; they only have the building blocks of proteins (amino acids).
If your patient has experienced a major burn, multisystem organ failure, trauma, or an extended illness, a specialized formula may be ordered to provide the adequate high calories and specific proteins needed for healing. Also, breast milk can be given to neonates through NG tubes if the mother pumps the milk beforehand and provides it to the NICU/PICU nurses.
Contraindications
Contraindications to NG tube placement are divided into two categories: absolute and relative. Absolute contraindications mean that the procedure may produce a life-threatening situation and should be avoided if possible. Relative contraindications mean that caution should be used because the possibility of an adverse event is possible; the benefits must outweigh the risks.
Absolute contraindications to NG tube placement are severe midface trauma and recent nasal, throat, or esophageal surgery. Severe midface trauma can easily compromise the patient's airway, and some facial and cranial vault bones are extremely thin and fragile. With midface trauma, you run the risk of the NG tube going through the cribriform plate of the ethmoid bone; if this happens, then the NG tube will be in the cranial vault with fatal results.
NG tubes should only be placed by a surgeon if being used for a patient who's undergone recent nasal, throat, or esophageal surgery. The risk of reopening the suture line is too great and can lead to serious post-op complications. Never replace a post-op NG tube that has inadvertently been removed; notify the surgeon immediately per your facility's policy.
Relative contraindications for NG tube placement include coagulation abnormalities, esophageal varices, esophageal stricture, and alkaline ingestion. The mucosal lining of the nasal passages is extremely thin and very vascular. If your patient has an uncorrected coagulation abnormality, you run the risk of epistaxis during NG tube insertion. Severe epistaxis is a true medical emergency; it can lead to airway compromise and/or aspiration of blood.
Esophageal varices are extremely dilated submucosal veins, usually in the lower third of the esophagus. The fact that the veins are so close to the surface of the esophagus makes it easy for them to start bleeding upon NG tube insertion. Treatment for bleeding varices focuses on stopping blood loss, maintaining plasma volume, and correcting any coagulation disorders.
Esophageal strictures are associated with scar tissue from gastroesophageal reflux disease, injuries from endoscopes, long-term use of NG tubes, swallowing caustic substances, and previous treatment for esophageal varices. The scar tissue isn't as pliable as normal esophageal tissue, making it easier to become damaged with the insertion of invasive tubes.
Although NG tubes are used for the management of overdoses, they should be used sparingly in cases of alkaline substance ingestion. With an NG tube in place, the cardioesophageal sphincter can't completely close, increasing the risk of reflux of the alkaline substance into the esophagus, causing further damage.
Contraindications in the pediatric population include congenital birth defects affecting the gastrointestinal tract, most specifically cleft lip and/or cleft palate.
Insertion tips
Follow these steps when inserting an NG tube for an adult patient.
1. Explain the procedure to the patient and obtain consent.
2. Gather the supplies needed.
3. Place the patient in an upright position; if unable, lay the patient on one side.
4. Agree on a signal with the patient that he or she can use to stop the procedure (such as raising the hand).
5. Wash your hands and put on gloves.
6. Measure the distance from the tip of the patient's nose, to his or her earlobe, and to the bottom of the xiphoid process (see NG tube measurement). Mark this length so you'll know when to stop advancing.
7. Lubricate the first 2 to 4 in of the tube with water-soluble lubricant.
8. Inspect the patient's nares for a deviated septum or visible nasal polyps; use the larger nares for your insertion.
9. Wash the patient's nose with warm water and soap, and dry completely.
10. Advance the tube slowly into the nares, aiming the tube horizontally, along the floor of the nasal cavity. If resistance is met, don't force the tube; withdraw and attempt at a different angle.
11. As the tube approaches the nasopharynx, ask the patient to swallow; with each swallowing motion the patient makes, advance the tube a little farther. If able and cooperative, ask the patient to tuck his or her chin, which causes the opening of the esophagus to widen.
12. Stop once you've advanced the tube to the mark you made while measuring.
13. Lightly tape the tube to the patient's cheek while you're confirming placement.
14. Confirm placement per your facility's policy. Ways to check placement include aspirating gastric contents and testing it with pH paper (a pH of 5.5 or less indicates gastric acid), or obtaining a chest X-ray. Special consideration: Average gastric pH is 1 to 3; with patients who are taking medication for acid reduction, the pH can be higher than 4.
15. Once placement is confirmed, tape the tube more securely to the patient's nose.
Monitoring maven
Nursing care of the patient with an NG tube is all about monitoring. You'll want to monitor your patient's serum electrolytes (sodium, potassium, magnesium, and phosphorus) whether he or she is receiving tube feedings or placed on suction. In patients receiving tube feedings, electrolytes are lost due to the osmolality of the tube feeding and the way the electrolytes move across the pressure gradient. With suction, these electrolytes will be lost with the gastric contents that are removed.
You'll also want to monitor your patient's daily weight and maintain strict intake and output; this will ensure that he or she is receiving the right amount of nutrients and water.
Monitor your patient's skin, especially the nares. NG tubes can cause skin breakdown of the nares if not monitored and repositioned frequently. You should change the position of the NG tube slightly every 24 hours to reduce the risk of skin breakdown. Remember that tube placement should be verified before use if intermittently being used and every 4 hours if being continuously used.
A useful tool
NG tubes can be used as both a diagnostic and treatment tool. With an NG tube, you can monitor your patient's condition, administer medications, and provide nutrients. NG tubes may be used for immediate protection of the airway in stroke patients with difficulty swallowing or for a moderate amount of time to provide nutrition to patients. With time and experience, you'll become comfortable with NG tubes to the benefit of your patients.
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