Nasogastric Intubation

Updated: May 13, 2022
Author: Gil Z Shlamovitz, MD, FACEP; Chief Editor: Vikram Kate, MBBS, PhD, MS, FACS, FACG, FRCS, FRCS(Edin), FRCS(Glasg), FIMSA, FFST(Ed), MAMS, MASCRS 



Gastric intubation via the nasal passage (ie, the 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.


Diagnostic indications for NG intubation include the following:

  • Evaluation of upper gastrointestinal (GI) bleeding (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
  • Identification of cancer cells - In a study of patients with gastric cancer, gastric lavage cytology samples collected via an NG tube inserted preoperatively were examined for the presence (GL1) or absence (GL0) of cancer cells; GL1 was significantly associated with poor overall survival and progression-free survival [1]

Therapeutic indications for NG intubation include the following:

  • 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
  • Feeding
  • Bowel irrigation
  • NG tube can be kept following corrosive ingestion for the development of a tract in the esophagus that subsequently can be used for balloon dilatation

Increased abdominal pressure from any cause predisposes patients to gastroesophageal regurgitation (GER), and NG tubes are used to prevent this in patients undergoing surgery with general anesthesia. Lai et al simulated increased abdominal pressure in 15 obese patients by means of laparoscopic pneumoperitoneum and Trendelenburg (LPT) positioning to assess whether NG tubes prevent GER.[2] Assessment was carried out via preinserted esophageal multichannel intraluminal and pH (MII-pH) monitoring. Thirteen patients (86%) developed GER while in the LPT position, indicating that preinserted NG tubes under general anesthesia are not likely to be protective in obese patients.

NG feeding is conventionally done preoperatively or postoperatively. After esophagectomy, however, a feeding jejunostomy is preferred to NG feeding. In a randomized controlled trial by Tao et al, 120 patients who underwent minimally invasive McKeown esophagectomy received either jejunostomy feeding (JF; n = 58) or NG feeding (NF; n = 62).[3] The two groups had similar rates of overall complications. In the first month after surgery, the JF group had a significantly higher body mass index (BMI): 23.6 ± 3.2 versus 20.9 ± 3.5. The JF group also had better global quality-of-life scores. Disease-free survival and overall survival were  similar in the two groups. 

Role in enhanced recovery after surgery (ERAS)

Although it has been traditional to place an NG tube (NGT) after all major GI surgical procedures for gastric decompression, many studies have shown that NG intubation is not mandatory in all cases. In a propensity score analysis of a prospective database (N = 1561), Venara et al compared patients who had an NG tube during colorectal surgery with those who did not.[4] The no-NGT group had significantly less postoperative nausea, better tolerance of early feeding, reduced postoperative morbidity, and fewer pulmonary complications; however, the risk of postoperative ileus was not significantly reduced in this group. 

In a prospective observational study that included 201 patients undergoing pancreaticoduodenectomy, Kleive et al found that 45 patients (22.4%) required NGT reinsertion after the operation and 32 (15.9%) underwent a relaparotomy.[5]  NGT reinsertion occurred in 26 of the patients who did not undergo a relaparotomy. The presence of a major postoperative complication was a risk factor for NGT reinsertion. Patients who required NGT reinsertion had a higher frequency of major postoperative complications and relaparotomy than those who did not. The authors concluded that routine use of an NGT after pancreaticoduodenectomy is not justified within an ERAS setting. 


Absolute contraindications for NG intubation include the following:

  • Severe midface trauma
  • Recent nasal surgery

Relative contraindications for NG intubation include the following:

  • Coagulation abnormality
  • Esophageal varices (usually, a Sengstaken-Blakemore tube is introduced, but an NG tube can be used for lower-grade varices) or stricture
  • Recent banding of esophageal varices
  • Anastomosis in the esophagus and the stomach - Blind NG tube insertion has traditionally been contraindicated in certain procedures involving these anastomoses because of the fear of damage to the staple line; however, in an animal study of blind NGT advancement after sleeve gastrectomy performed via a flexible gastroscope, Fabian et al observed no sign of trauma to the staple line and no significant mucosal injury (there were several small petechiae of the gastric mucosa, none of which were of full thickness or penetrated the mucosa) [6]
  • Alkaline ingestion (the tube may be kept if the injury is not severe)

Periprocedural Care


The following equipment is needed for nasogastric (NG) intubation (see the image below):

  • NG tube (for adult patients) - 16-18 French
  • NG tube (for pediatric patients) - In pediatric patients, the correct tube size varies with the patient's age; to find the correct size (in French), add 16 to the patient's age in years and then divide by 2, so that for an 8-year-old child, for example, the correct size is 12 French ([8 + 16]/2 = 12)
  • Viscous lidocaine 2%
  • Oral analgesic spray (benzocaine spray or other)
  • Syringe, 10 mL
  • Glass of water with a straw
  • Water-based lubricant
  • Toomey syringe, 60 mL
  • Tape
  • Emesis basin or plastic bag
  • Wall suction, set to low intermittent suction
  • Suction tubing and container
Equipment for nasogastric intubation. Equipment for nasogastric intubation.

Patient Preparation


Various methods of topical anesthesia for NG intubation have been proved to be effective in pain relief and to improve the likelihood of successful NG intubation.[7, 8, 9, 10, 11]

The use of viscous lidocaine (ie, the sniff and swallow method) was found to significantly reduce the pain and gagging sensation associated with NG tube insertion.[12]  Viscous lidocaine is discussed in more detail in the Technique section below.

Alternative techniques include the following:

  • Nebulization of lidocaine 1% or 4% through a face mask (≤ 4 mg/kg; not to exceed 200 mg per dose in adults) is an option; the authors recommend that a preservative-free lidocaine (ie, intravenous lidocaine) be used for nebulization in order to minimize the risk of allergic reaction
  • An anesthetic spray that contains benzocaine or a tetracaine/benzocaine/butyl aminobenzoate combination may be applied to the nasal and oropharyngeal mucosa; be advised that incidents of methemoglobinemia after a single use of benzocaine topical sprays have been reported to the US Food and Drug Administration (FDA); for more information, see  Anesthesia, Topical


The patient should be seated in an upright position.



Placement of Nasogastric Tube

Explain the procedure of nasogastric (NG) intubation, as well as its benefits, risks, complications, and alternatives, to the patient or the patient's representative.

Examine the patient's nostril for septal deviation. To determine which nostril is more patent, ask the patient to occlude each nostril and breathe through the other.

Instill 10 mL of viscous lidocaine 2% (for oral use) down the more patent nostril with the head tilted backward (see the images below), and ask the patient to sniff and swallow to anesthetize the nasal and oropharyngeal mucosa. In pediatric patients, do not exceed 4 mg/kg of lidocaine. Wait 5-10 minutes to ensure adequate anesthetic effect.

Aspiration of viscous lidocaine into a syringe. Aspiration of viscous lidocaine into a syringe.
Instillation of viscous lidocaine 2%. Instillation of viscous lidocaine 2%.

Estimate the length of insertion by measuring the distance from the tip of the nose, around the ear, and down to just below the left costal margin. This point can be marked with a piece of tape on the tube. When using the Salem sump NG tube (Kendall, Mansfield, MA) in adults, the estimated length usually falls between the second and third preprinted black lines on the tube (see the image below).

Estimation of nasogastric tube length from nostril Estimation of nasogastric tube length from nostril to stomach.

Apart from the nose-to-ear-to-xiphisternum (NEX) method, several other methods for determining the length of the tube have been described. Among the various options, a formula based on gender, weight, and nose-to-umbilicus measurement while lying flat was found to be safer and more accurate in a study by Santos et al.[13]

Position the patient sitting upright with the neck partially flexed. Ask the patient to hold the cup of water in his or her hand, and put the straw in his or her mouth. Lubricate the distal tip of the NG tube (see the image below).

Nasogastric tube lubrication with water-based lubr Nasogastric tube lubrication with water-based lubricant.

Gently insert the NG tube along the floor of the nose, and advance it parallel to the nasal floor (ie, directly perpendicular to the patient's head, not angled up into the nose) until it reaches the back of the nasopharynx, where resistance will be met (10-20 cm). At this time, ask the patient to sip on the water through the straw and start to swallow (see the image below). Continue to advance the NG tube until the distance of the previously estimated length is reached (see the video below).

Patient flexing his neck and drinking water while Patient flexing his neck and drinking water while a nasogastric tube is inserted.
Nasogastric tube insertion.

If, at any time, the patient experiences respiratory distress, is unable to speak, or has significant nasal hemorrhage, or if the tube meets significant resistance, stop advancing the tube and withdraw it completely. 

Fan et al described a no-swallow technique of NG tube intubation that relieved patient discomfort during the procedure.[14]  In this technique, when the tube reached the pharynx, patients were required to take a deep breath and hold it, instead of swallowing as in the conventional technique. During breath-holding, the epiglottis covers the throat and the glottis closes, thereby reducing the likelihood of the tube entering the trachea. When the tube was inserted 15-20 cm, the patient was required to perform abdominal breathing to reduce discomfort and avoid failure of tube intubation (some patients can only hold their breath for a short time).

This no-swallow technique was found to yield an increase in the success rate at first intubation, as well as reductions in the occurrence of nausea, tearing, mucosal injury, and changes in vital signs (heart rate, breath, systolic pressure), when compared with the technique used in the control group.[14]

Verify proper placement of the NG tube by auscultating a rush of air over the stomach using the 60 mL Toomey syringe (see the first image below) or by aspirating gastric content. The authors recommend always obtaining a chest radiograph (see the second image below) in order to verify correct placement, especially if the NG tube is to be used for medication or food administration. Colorimetric capnography is another valid method for verifying NG tube positioning in mechanically ventilated patients.[15]

Auscultation over the stomach. Auscultation over the stomach.
Nasogastric tube in lung. Nasogastric tube in lung.

In a retrospective descriptive analysis (N = 215) aimed at identifying factors associated with insufficient NG tube visibility on radiography, Torsy et al reported that in 14.9% of patients, the image quality was insufficient to determine the position of the tube.[16] The factors associated with poor visibility were high body mass index (BMI), male sex, and the absence of a guide wire inside the NG tube at the time of chest radiography.

Although radiographic confirmation of NG tube position is conventionally considered the gold standard, it exposes the patients to ionizing radiation. Choi et al reported the use of a sonographic method to confirm the placement of nasogastric tube in pediatric patients.[17]  They found that this method yielded good esophageal imaging; however, the gastric imaging was challenging, and it was improved by injecting an air bolus.

Manometry is another safe and reliable method for differentiating airway placement of an NG tube from gastric placement.[18] A biphasic pressure change synchronous with airway pressure during mechanical ventilation indicates airway misplacement, and a pressure change during compression of the epigastric area indicates a gastric placement.

Apply benzoin or another skin preparation solution to the nose bridge. Tape the NG tube to the nose to secure it in place (see the image below). If clinically indicated, attach the tube to wall suction after verification of correct placement.

Secured nasogastric tube. Secured nasogastric tube.


During insertion, if concern exists that the NG tube is in the incorrect place, ask the patient to speak. If the patient is able to speak, then the tube has not passed through the vocal cords and/or lungs.

The NG tube may coil in the nasopharynx or oropharynx. If this occurs, or if the tube is difficult to pass in general, try curling the distal end and partially freezing it in a cup of ice so it temporarily holds its curled shape better. Insert the lubricated tube tip through the nose with the curled end pointing downward. Once the distal tip passes into the hypopharynx, the curved tip faces anteriorly. Rotate the tube 180º so that the curved end points posteriorly toward the esophagus. Continue to insert in the usual manner by having the patient swallow water.

Another option (applicable only in patients who are sedated and paralyzed) is to place two or three fingers through the patient’s mouth into the oropharynx. The fingers are used to guide the NG tube into the hypopharynx.

Lifting the thyroid cartilage anterior and upward might open the esophagus and allow passage into the proximal esophagus.

A method of freezing an NG tube with distilled water was shown to increase the success rate of insertion for intubated patients.[19]

Direct laryngoscopy or video laryngoscopy can aid in placing an NG tube in sedated patients by enabling visualization of the tip entering the esophagus.[20]

A randomized crossover manikin trial conducted by Li et al introduced a newer technique of gastric tube placement via an 8.4-French deflection flexible ureteroscope, which served as a visual guidance system.[21] Placement time was substantially shorter and the incidence of procedure-related complications considerably lower than with the standard method.

In a study by Lee et al that used a manikin simulator, the time required for NG tube placement was reduced significantly in both intubated and nonintubated patients if the procedure was done under visualization with a video-guided laryngoscope, as compared with manual and laryngoscope-assisted intubation.[22]

Endotracheal tube assistance and video laryngoscopy can be used to facilitate NG tube insertion in anesthetized and intubated patients. The success rate is increased, and complications such as kinking of the tube are reduced.[23]

Although pH, enzyme, bilirubin, and carbon dioxide testing have been used to distinguish respiratory from gastrointestinal placement of NG tubes, none of these methods has enabled detection of tube placement in the esophagus or gastroesophageal junction.[24] Therefore, the authors recommend the routine use of x-ray verification.

A survey of critical care nurses around the United States showed that recommendations from multiple national-level organizations to obtain radiographic confirmation that each blindly inserted feeding tube is correctly positioned before the first use of the tube are not adequately implemented.[25] Auscultation is widely used despite recommendations to the contrary.

In a randomized, controlled study that included 200 anesthetized patients, Appukutty et al found that three techniques can increase the success rate of NG tube placement.[26] The use of a ureteral guide wire as stylet or a slit endotracheal tube as an introducer increased the success rate in comparison with control subjects, though the latter technique significantly lengthened the time for insertion. However, head flexion with lateral neck pressure proved to be the easiest technique, with a high success rate and the lowest complication rate.

Sharma et al described the use of a bubble technique for NG tube insertion, which they found to have higher confirmation rate than the conventional technique (76.8% vs 59.7%).[27]  In this technique, 2% lidocaine jelly was added to the proximal end to form a single bubble, and tube placement was later confirmed by means of fluoroscopy.


Some degree of patient discomfort is common. Generous lubrication, the use of topical anesthetic, and a gentle technique may reduce the patient’s level of discomfort. Throat irritation may be reduced with administration of anesthetic lozenges (eg, benzocaine lozenges) prior to the procedure.

Epistaxis may be prevented by generously lubricating the tube tip and using a gentle technique. Other complications that may occur are respiratory tree intubation and esophageal perforation.

The NG tube safety pack developed by Leeds Medical School in the United Kingdom is an innovative approach to reducing complications that makes guideline recommendations accessible and easy to follow by incorporating them into the pack design.[28] Innovations such as this can help anticipate and mitigate errors in the placement of an NG tube.

A rare complication, an NG tube knotting around an endotracheal tube, can happen when a nasal endotracheal tube is used along with the NG tube.[29]  

In an integrative review of 69 primary studies focusing on adverse events following NG tube placement, Motta et al reported that such events are relatively common and that the majority of them are respiratory which increase rates of hospitalization, death, or both.[30]


Questions & Answers


What is nasogastric (NG) intubation?

What are diagnostic indications for nasogastric (NG) intubation?

What are therapeutic indications for nasogastric (NG) intubation?

What are absolute contraindications for nasogastric (NG) intubation?

What are relative contraindications for nasogastric (NG) intubation?

Periprocedural Care

What equipment is necessary for nasogastric (NG) intubation?

What is the role of viscous lidocaine in nasogastric (NG) intubation?

Which anesthetic techniques are used for nasogastric (NG) intubation?

What position should a patient be in during nasogastric (NG) intubation?


Before nasogastric (NG) intubation, what information should patients receive?

Which nasal exam is performed prior to nasogastric (NG) intubation?

How should anesthetic be administered before nasogastric (NG) intubation?

How is the tube length estimated prior to nasogastric (NG) intubation?

What is the alternative to the NEX method for determining the tube length prior to nasogastric (NG) intubation?

What steps should be completed before inserting a nasogastric (NG) tube?

How should a nasogastric (NG) tube be inserted and advanced?

How is respiratory distress during nasogastric (NG) intubation managed?

What technique can be used to relieve patient discomfort during nasogastric (NG) intubation?

How is proper placement of the nasogastric (NG) tube verified?

What is the role of manometry during nasogastric (NG) tube placement?

How should the nasogastric (NG) tube be secured?

What should be done if the nasogastric (NG) tube is suspected of being placed incorrectly?

What steps should be taken if a nasogastric (NG) tube is coiled or difficult to pass?

What is the role of radiography in detecting nasogastric (NG) tube misplacement?

Which techniques increase the success rate for nasogastric (NG) tube placement?

How is a patient's discomfort reduced during nasogastric (NG) intubation?

What are possible complications of nasogastric intubation?

How are complications of a nasogastric intubation reduced?