Gastric intubation via the nasal passage (ie, nasogastric route) is a common procedure that provides access to the stomach for diagnostic and therapeutic purposes. A nasogastric (NG) tube is used for the procedure. The placement of an NG tube can be uncomfortable for the patient if the patient is not adequately prepared with anesthesia to the nasal passages and specific instructions on how to cooperate with the operator during the procedure.
- Evaluation of upper gastrointestinal (GI) bleed (ie, presence, volume)
- Aspiration of gastric fluid content
- Identification of the esophagus and stomach on a chest radiograph
- Administration of radiographic contrast to the GI tract
- Gastric decompression, including maintenance of a decompressed state after endotracheal intubation, often via the oropharynx
- Relief of symptoms and bowel rest in the setting of small-bowel obstruction
- Aspiration of gastric content from recent ingestion of toxic material
- Administration of medication
- Bowel irrigation
- Absolute contraindications
- Severe midface trauma
- Recent nasal surgery
- Relative contraindications
- Coagulation abnormality
- Esophageal varices or stricture
- Recent banding or cautery of esophageal varices
- Alkaline ingestion
The main complications of NG tube insertion include aspiration and tissue trauma. Placement of the catheter can induce gagging or vomiting, therefore suction should always be ready to use in the case of this happening.
The potential for contact with a patient’s blood/body fluids while starting an NG is present and increases with the inexperience of the operator. Gloves must be worn while starting an NG; and if the risk of vomiting is high, the operator should consider face and eye protection as well as a gown. Trauma protocol calls for all team members to wear gloves, face and eye protection and gowns.
All necessary equipment should be prepared, assembled and available at the bedside prior to starting the NG tube. Basic equipment includes:
- Personal protective equipment
- NG/OG tube
- Catheter tip irrigation 60ml syringe
- Water-soluble lubricant, preferably 2% Xylocaine jelly
- Adhesive tape
- Low powered suction device OR Drainage bag
- Cup of water (if necessary)/ ice chips
- Emesis basin
- pH indicator strips
1. Gather equipment.
2. Don (put on) non-sterile gloves.
3. Explain the procedure to the patient and show equipment.
4. If possible, sit patient upright for optimal neck/stomach alignment.
5. Examine nostrils for deformity/obstructions to determine best side for insertion.
7. Mark measured length with a marker or note the distance.
8. Lubricate 2-4 inches of tube with lubricant (preferably 2% Xylocaine). This procedure is very uncomfortable for many patients, so a squirt of Xylocaine jelly in the nostril, and a spray of Xylocaine to the back of the throat will help alleviate the discomfort.
Instruct the patient to swallow (you may offer ice chips/water) and advance the tube as the patient swallows. Swallowing of small sips of water may enhance passage of tube into esophagus.
If resistance is met, rotate tube slowly with downward advancement toward closes ear. Do not force.
10. Withdraw tube immediately if changes occur in patient’s respiratory status, if
tube coils in mouth, if the patient begins to cough or turns pretty colors.
11. Advance tube until mark is reached.
12. Check for placement by attaching syringe to free end of the tube, aspirate sample of gastric contents. Do not inject an air bolus, as the best practice is to test the pH of the aspirated contents to ensure that the contents are acidic. The pH should be below 6. Obtain an x-ray to verify placement before instilling any feedings/medications or if you have concerns about the placement of the tube.
13. Secure tube with tape or commercially prepared tube holder.
14. If for suction, remove syringe from free end of tube; connect to suction; set machine on type of suction and pressure as prescribed.
15. Document the reason for the tube insertion, type & size of tube, the nature and amount of aspirate, the type of suction and pressure setting if for suction, the nature and amount of drainage, and the effectiveness of the intervention.
It is important to chose the most patent side by having the patient alternatively breath through each nostril independently. The presence of polyps are generally not considered a contraindication to this procedure, but it may be made easier by the application of a topical vasoconstrictor first, allowing a minute or 2 for the medication to take effect. If the tube meets with significant obstruction, continuous, gentle pressure often allows passage. If the tube cannot be passed through either side, it may be necessary to insert the tube orally. If a tube is absolutely necessary, the oral route can be used. The technique is generally the same as for nasal insertion although greater attention to topical anesthesia is necessary as most patients find this procedure to be extremely uncomfortable. Oral tubes are generally not recommended for long term use, except in intubated patients. They may be helpful for diagnostic purposes when they can be removed in a short time.
Failure of Tube to Pass Into Esophagus / Curling of the Tube
Difficulty may be encountered in passing the tube from the oropharynx into the esophagus, especially if the tube tends to curl. Occasionally the NGT will curl 180° and the distal tip will protrude through the oral cavity. Several remedies are possible. Maneuvers to increase the rigidity of the tube may be employed. After several attempts at passage, NGTs tend to become more flexible, and using a new NGT may increase your chances of successful passage. Some authorities recommended cooling the NGT in an ice bath to increase rigidity. Care must be utilized when using this technique as injuries to the soft tissues of the pharynx and esophagus are more likely with a cooled, rigid tube. Flexing the neck (in patients without cervical spine injury) brings the esophagus into a more anterior position and may facilitate passage as well. Bending the tube in the direction it will ultimately take may be helpful. The tube is inserted with the convex side up initially and then, as it reaches the lower pharynx, it is rotated 180 degrees so that the tube passes posteriorly and into the esophagus.
These patients are unable to assist you by swallowing, and passage into the esophagus may be difficult. Furthermore, in the supine patient, gravity may cause the esophagus to collapse and impede passage, causing the NGT to curl. If the patient does not have intact airway reflexes, it is possible to insert a laryngoscope into the oropharynx and directly visualize the tube. This visualization alone may be enough to facilitate passage. If further manipulation is required, a Magill forceps or the operators fingers may be inserted into the posterior oral cavity to help advance the tube. Anteriorly-directed traction on the mandible (using either the jaw-thrust maneuver or gentle manual traction on the patient’s lower teeth and chin) will often open the esophagus and allow the tube to pass through. A variation of this technique utilizes anterior traction on the thyroid cartilage to open the esophagus. It should be noted that in the intubated patient, the Salem or Levin tube may be passed orally.
Hemorrhage / Coagulopathy
Bleeding disorders do not generally represent a contraindication to tube placement. However, bleeding after insertion may sometimes be significant. The likelihood of major bleeding can be diminished by application of a vasoconstrictor to the entire nasal mucosa by atomization and the waiting several minutes for the medication to take effect.
3. Naeije R, Salingret E, Clumeck N, et al. Is Nasogastric Suction Necessary in Acute Pancreatitis? BMJ 1978;2:659-660.
4. Dees G. Difficult nasogastric tube insertions. Emergency Medicine Clinics of North America 1989; 7(1):177- 182.