by Sara Nikolić and Gregor Prosen
Nasogastric (NG) tube placement is one of the most common procedures performed in intensive care settings, the emergency department, and hospital wards. It is frequently used for the management of patients who require compression of the gastrointestinal (GI) tract, diagnosis and assessment, nutritional support and medication administration. The procedure is rapid, simple, and straightforward. The goal is to conduit the NG tube to the stomach through the nasal cavity, nasopharynx, oropharynx, and esophagus that enters the stomach below the diaphragm. The very vascular nasal mucosa lines the nasal cavity. This is important to remember because, after each unsuccessful insertion, incidences of mucosal bleeding and hemodynamic complication increase.
A 47-year-old man presents to your ER complaining of nausea and vomiting. He tells you that vomiting started a couple of hours after eating dinner the night before. It was a normal vomit, consist of digested food; however, it is not associated with meals. He has barely eaten during the past 36 hours. The pain consists of cramping and is vaguely umbilical, but it is not well localized. He gets mild relief from vomiting and says the pain is severe (9/10). He has felt generally unwell and has not taken his temperature. None of his close contacts have reported any vomiting. His last bowel movement was yesterday morning, and he cannot recall passing any flatus today. About 20 years ago he had an appendicectomy.
On examination, the patient is lying in bed in some discomfort from the stomach cramps. He has an appendicectomy scar and mild distension of his abdomen. You hear high-pitched bowel sounds on auscultation.
Vital signs are as follows: temperature of 36.6°C, heart rate of 66 bpm, blood pressure 126/63 mmHg, respiratory rate 11/min, oxygen saturation 98% on room air.
Blood tests come back and show: white cell count 7.7 × 109 cells/L, CRP 23 mg/L, Na 137 mM, K 3.7 mM, AST 27 U/L, ALT 23 U/L, ALP 29 U/L, amylase 152 U/dL, urea 4.2 mM, creatinine 92 µM.
The bedside ultrasound shows distended (>3 cm diameter) small bowel with numerous valvule conniventes and increased peristalsis with whirling motion of the bowel contents.
- Evaluation of upper gastrointestinal (GI) bleeding
- Identification of the esophagus and stomach on a chest x-ray
- Aspiration of gastric fluid content
- Administration of radiographic contrast to the GI tract
- Gastric decompression
- Relief of symptoms and bowel rest in the small-bowel obstruction
- Gastric content aspiration for recent toxic ingestions
- Administration of medications such as active charcoal
- Bowel irrigation
- NG tube can be kept following corrosive ingestion for the development of a tract in the esophagus. It subsequently can be used for balloon dilatation.
- Aspiration of gastric fluid content
- Absolute contraindications for NG tube placement are:
- Severe midface trauma – rare perforation through the thin cribriform plate of the ethmoid bone and into the brain can occur. Patients with facial trauma are best served with orogastric intubation.
- Recent nasal surgery
- Relative contraindications for NG placement are:
- Coagulation abnormality
- Esophageal varices (usually, a Sengstaken-Blakemore tube introduced, but an NG tube can be used for lower-grade varices) or stricture
- Recent banding of esophageal varices
- Alkaline ingestion (the tube may be kept if the injury is not severe)
Equipment and Patient Preparation
- Choose the size of nasogastric tube that is appropriate for the patient. A size 16 to 18 French is typically used for an adolescent or adult patient.
- Personal protective equipment
- A water-soluble lubricant is often enough to facilitate passage.
- If topical anesthesia is available: 1.5 mL of atomized lidocaine may be atomized into the nasopharynx, with 3 mL applied to the oropharynx and swallowed, or 5 ml of 2% lidocaine jelly can be injected into the nostril. Do not use oil-based lubricant.
- Cup of water with a straw
- Emesis basin and towel
- Tongue blade and flashlight
- Aspirating and irrigating syringes (10ml and Toomey syringe, 60 mL)
- Tincture of benzoin, scissors, and tape or semipermeable transparent membrane dressing
- pH indicator paper
- Suction tubing and container
- Wall suction, set to low intermittent suction
General patient preparation
- Give the patient nothing by mouth for several hours (ideally).
- Explain the procedure to the patient, including route, purpose, and anticipated duration of intubation.
- Have the patient sit upright or raise the head of the bed. If this is not possible, passing the tube with the patient in the left lateral decubitus position has less risk of aspiration than if the patient is supine.
- Check for nasal obstruction or maxillofacial trauma. Have the patient inhale briskly through each nostril and use the more patent nostril for intubation.
- Test the gag reflex. Patients unable to gag are at increased risk of pulmonary aspiration.
- Wash hands
- Introduce yourself and confirm patient details
- Explain the procedure and gain consent
- Gather equipment for the procedure
- Inspect the nostrils for septal deviation – to determine which nostril is more patent, ask the patient to occlude each nostril and breathe through the other
- Position the patient sitting upright with their neck partially flexed
- Put the gloves on
- If available, put the anesthetic spray to the back of the patient’s throat for comfort
- Estimate the length of insertion by measuring the distance from the tip of the nose, around the ear, and down to 5cm below the xiphisternum. This point can be marked with a piece of tape on the tube.
- Ask the patient to hold the cup of water and put the straw in his or her mouth.
- Lubricate the tip of the NG tube
- Place the kidney plate near the patient in case there is leakage.
- Warn patient you will start the procedure and in case of pain they should tip you on the hand.
- Gently insert the NG tube along the floor of the nose. Advance NG tube parallel to the nasal floor (not angled up into the nose) until it reaches the back of the nasopharynx, where resistance will be met (10-20 cm).
- At this moment, ask the patient to sip water through the straw and start swallowing. With each sip you continue to advance the NG tube until the distance of the previously estimated length is reached.
- Confirm the tube’s placement in the stomach by radiographic imaging. Alternatively, gently aspirate gastric contents with a 3-cc syringe, and check the pH. A pH < 4 suggests the tip is in a gastric location. A pH > 5 does not reliably predict location because the respiratory system and intestinal tract distal to the pylorus often have a pH > 5. Verifying tube position by auscultating a rush of air over the stomach using the 60 mL Toomey syringe is not as helpful because the sounds of air in the bronchial tree can be mistaken for gastric insufflation.
- Apply benzoin or another skin preparation solution to the nose bridge. Tape the NG tube to the nose to secure it in place.
- If clinically indicated, attach the tube to wall suction after verification of correct placement.
- Dispose of used equipment into a clinical waste bin and wash hands.
- Explain to patient that the procedure is over. Reassure that the NG tube will become more comfortable over the next few hours. Offer patient paper towels to clean their face and nose. Document clearly the procedure.
Withdraw the nasogastric tube if, at any time resistance, respiratory distress, the inability to speak, or significant nasal hemorrhage occurs.
Hints and Pitfalls
- During insertion, if concern exists that the NG tube is in the wrong place, ask the patient to speak. If the patient can speak, then the tube has not passed through the vocal cords and/or lungs.
- To improve the success rate of nasogastric tube placement, provide external and medially directed pressure on the ipsilateral neck at the level of the thyrohyoid membrane. It will collapse the piriform sinus and eliminate it as a potential site for impaction. This maneuver was successful for difficult nasogastric intubation in 85 percent of patients.
- The nasogastric tube may coil in the oropharynx, mouth, or hypopharynx. Cool the tube in cold tap water or ice water for 5 minutes to make the tube stiffer and then reinsert it. A larger bore tube may be inserted more easily. A final option is to place several fingers through the patient’s mouth and into the oropharynx. The fingers can be used to guide the tube against the posterior oropharyngeal wall and into the hypopharynx. Do not attempt this unless the patient is unconscious or paralyzed to prevent them from biting the fingers.
- The risk for tube misplacement is greater in the intubated patient who is unable to assist with nasogastric intubation. Observe that there are no changes in the patient’s oxygen saturation when inserting the nasogastric tube. It is very easy for the nasogastric tube to pass by the cuff of an endotracheal tube without much resistance.
- GlideScope facilitates NG tube insertion and reduces the duration of the procedure in anesthetized patients. Also, esophageal guidewire-assisted insertion with manual forward laryngeal displacement technique most frequently results correct positioning of the NG tube in anesthetized and tracheally intubated patients after the first attempt.
- American Association of Critical-Care Nurses partook a survey about feeding tube practices in adult intensive care units. The recommendations were to obtain radiographic confirmation that each blindly inserted tube is correctly positioned before the first use, which is currently not adequately implemented. Also, auscultation is widely used despite recommendations to the contrary.
Post Procedure Care and Recommendations
- The patient should be able to speak without respiratory distress immediately after placement of the nasogastric tube. Observe the patient for complaints of neck pain, substernal chest pain, dysphagia, drooling, trismus, fever, or subcutaneous and mediastinal air. These would be signs of esophageal perforation or errant placement of the nasogastric tube.
- Although auscultation of air in the stomach has been classically used to determine correct placement, air insufflated into the pleural space or the esophagus after misplacement of the tube can be just as easily heard over the upper abdomen.
- Gastric contents should be able to be aspirated through the nasogastric tube.
- Testing the pH of the gastric contents can help predict the placement of the nasogastric tube. However, in one trial, pH of 4 was able to accurately identify the location of only 56% of all NG feeding tubes when compared with the reference standard radiography. The use of H2 blockers makes the assessment of gastric pH difficult. Radiographic demonstration of the tube in the antral or fundal portion of the stomach is the preferred method of confirmation.
- The most common complication of nasogastric intubation is discomfort in the nasopharynx and oropharynx.
- Placement in the nares can result in epistaxis if the nasal mucosa is irritated, abraded, or ulcerated.
- These complications can be reduced or avoided with generous lubrication of the nasogastric tube and the installation of topical anesthetics and vasoconstrictors.
- Sinusitis may occur from the nasogastric tube obstructing the sinus ostia. These complications are usually of no clinical significance.
- A more serious consequence of nasogastric intubation is misplacement into the respiratory tree. This is estimated to occur in up to 15% of cases. The incidence increases in frequency with a patient who has a diminished gag reflex or a decreased level of consciousness. The presence of a cuffed endotracheal tube does not preclude passage into the respiratory tree. The nasogastric tube will pass the cuff of the endotracheal tube without significant resistance. Advancing the tube into the airway can result in perforation of a bronchus or the lung and result in a pneumothorax, hydropneumothorax, pulmonary hemorrhage, empyema, or bronchopulmonary fistula. These complications are increased if medication or alimentation is infused into the respiratory tree.
- The most serious complication of nasogastric tube placement is the esophageal perforation. This most often occurs in the posterior wall of the cervical portion of the esophagus and through the cricopharyngeus muscle. Risk factors for esophageal perforation include a preexisting esophageal abnormality, altered mental status, cervical osteophytes, cardiomegaly, tracheal intubation, a rigid nasogastric tube, and multiple attempts. Perforation often results in mediastinitis with a subsequent mortality rate of up to 30%. Prompt recognition, surgical repair, and parenteral antibiotics can reduce the mortality rate to less than 10%. The use of softer and smaller nasogastric tubes with generous lubrication can reduce the risk of esophageal perforation.
Pediatric, Geriatric, Pregnant Patient, and Other Considerations
The placement of a nasogastric tube in children is often difficult. Their large tonsils and adenoids may hinder the passage of the nasogastric tube. These tissues are soft, easily injured, and may bleed as the nasogastric tube is passed. The tongue, large by comparison with adults, may push into the oropharynx and impede the passage of the nasogastric tube. Their nostrils and nasal passage are quite small and limit the size of nasogastric tube that may be passed. Also, size is calculated by the formula ((age in years + 16) / 2). Typical sizes include 8 French for infants, 10 to 12 French for small children, and 12 to 14 French for older children. Most common complications are nasal ala pressure sores that are usually not associated with significant morbidity and mortality.
References and Further Reading
- Agha R, Siddiqui MRS. Pneumothorax after nasogastric tube insertion. JRSM Short Reports. 2011 Apr;2(4). PubMed PMID: 21541076.
- JBI. Methods for determining the correct nasogastric tube placement after insertion in adults2010; 14(1):[1-4 pp.]. Available from: http://connect.jbiconnectplus.org/ViewSourceFile.aspx?0=5384.
- Leschke RR. Nasogastric Intubation. In: Reichman EF, Simon RR, editors. Emergency Medicine Prodecures. Columbus, OH: McGraw-Hill 2004. p. 413-20.
- Ghatak T, Samanta S, Baronia AK. A New Technique to Insert Nasogastric Tube in an Unconscious Intubated Patient. North American Journal of Medical Sciences. 2013 Jan;5(1):68-70. PubMed PMID: 23378961.
- Shlamovitz GZ. Nasogastric Intubation [updated Aug 17, 2015; cited 2016 May 21]. Available from: http://emedicine.medscape.com/article/80925-overview#a1.
- Grunkemeier DMS. Oral and Nasal Gastrointestinal Intubation. In: Drossman DA, Grimm IS, Shaheen NJ, editors. Handbook of Gastroenterologic Procedures 4th ed. Philadelphia, PA LIPPINCOTT WILLIAMS & WILKINS; 2005. p. 21-30.
- Moharari RS, Fallah AH, Khajavi MR, Khashayar P, Lakeh MM, Najafi A. The GlideScope facilitates nasogastric tube insertion: a randomized clinical trial. Anesthesia and analgesia. 2010 Jan 1;110(1):115-8. PubMed PMID: 19861362. Epub 2009/10/29. eng.
- Kirtania J, Ghose T, Garai D, Ray S. Esophageal guidewire-assisted nasogastric tube insertion in anesthetized and intubated patients: a prospective randomized controlled study. Anesthesia and analgesia. 2012 Feb;114(2):343-8. PubMed PMID: 22104075. Epub 2011/11/23. eng.
- Metheny NA, Stewart BJ, Mills AC. Blind insertion of feeding tubes in intensive care units: a national survey. American journal of critical care : an official publication, American Association of Critical-Care Nurses. 2012 Sep;21(5):352-60. PubMed PMID: 22941709. Epub 2012/09/04. eng.
- Seyedhejazi M, Hamidi M, Sheikhzadeh D, Aliakbari Sharabiani B. Nasogastric Tube Placement Errors and Complications in Pediatric Intensive Care Unit: A Case Report. Journal of cardiovascular and thoracic research. 2011;3(4):133-4. PubMed PMID: 24250971
- CliniSips – nasogastric tube insertion – https://www.youtube.com/watch?v=en5ctZInOyA – link
- Geeky Medics – Nasogastric (NG) Tube Insertion – OSCE Guide – https://youtu.be/WZvIw0SnYrE – link