What is the most reliable method to confirm the placement of a newly inserted nasogastric NG tube?

A nasogastric (NG) tube is a long, thin, hollow tube that is passed through a nostril into the throat and down into the stomach. 

NG tubes are used to provide hydration, medications, and enteral feeds to children who are unable to safely take food or liquids by mouth or to supplement oral intake. 

While often used in home care and considered safe to do so in many instances, risks associated with use of NG tubes include displacement with the potential to cause discomfort with feeding and aspiration to the lungs.

ASSESSMENT:

Routine assessment of checking the placement of NG tubes before their use enables verification that the tube is still in the stomach and safe to use. 

NG tube placement is to be assessed:

• Before each use of the tube for feeds and/or medications

• When a new tube is inserted

• When there is concern that the tube may have been pulled out or changed position

• There is choking, vomiting, coughing or breathing trouble

• Every 8 hours during a continuous feed 

RECOMMENDATION:

Connected Care recommends following the most up to date best practice for checking NG tube placement. This involves assessing the pH of stomach contents aspirated from the tube. 

Auscultation and listening for a gastric "pop" is NOT a reliable method for checking NG tube placement and should NEVER be used to confirm tube placement

To Check NG Tube Placement

1. Attach an empty syringe to the NG tube and gently flush with air to clear the tube. Then pull back on the plunger to withdraw stomach contents.

2. Empty the stomach contents on to all three squares on the pH testing paper and compare the colors with the label on the container. 

For most children, the colour on the strip should be less than 4 (pH<4). 
For children on stomach acid suppressing medications or who have just been fed, the reading should be less than 6 (pH<6).

These readings indicate the NG tube placement is correct and the tube is safe to use. You may flush the tube and proceed to use.  

Click here for step by step instructions for each method including a video on venting

A malpositioned nasogastric tube, improper feeding site, large gastric volume and supine position are the main risk factors for aspiration during enteral feeding. When enteral formulations or medications enter the lung through a nasogastric tube inadvertently positioned in the respiratory tract, the life-threatening complication that results is referred to as “aspiration by proxy” (Figure 1).1

Auscultation is most often used at the bedside to check for appropriate placement of a nasogastric tube. Sound generated by air blown through the tube is used to determine tube placement in the gastrointestinal tract. However, a similar gurgling can be heard over the epigastrium when the tube has been incorrectly placed into the tracheobronchial tree, pleural space or esophagus.2,3

Aspirate from a tube placed in the stomach is usually grassy green or colourless, with shreds of off-white to tan mucus. The aspirate often has a pH of 5 or less. In the absence of infection, respiratory secretions are usually clear. However, measuring the pH level alone does not differentiate between respiratory and gastrointestinal placement of the tube; both sites can have high pH values (> 6).4 The pH test has no value if the patient is receiving acid suppression medication.

In situations where the patient may have suppressed gag or cough reflexes (e.g., decreased level of consciousness or neurologic debilitation), the absence of coughing or choking after placement of the tube may be misleading. Research continues into simple bedside methods for determining appropriate placement of nasogastric tubes.

An abdominal radiograph is considered the “gold standard” for determining the position of a nasogastric tube, especially in a critically ill, elderly, dysphagic or unconscious patient.5

“Five things to know about …” is a new series that presents key statements on topics of interest to physicians. For author instructions, go to cmaj.ca.

Previously published at www.cmaj.ca

Competing interests: None declared.

This article has been peer reviewed.

Articles from CMAJ : Canadian Medical Association Journal are provided here courtesy of Canadian Medical Association

A 78-year-old alert woman in hospital was being fed through a nasogastric tube because of deconditioning. She was taking acetylsalicylic acid for ischemic cardiomyopathy, and a vitamin K antagonist for atrial fibrillation and a recent axillobifemoral bypass thrombosis. She had a permanent right-side nephrostomy after receiving an injury to the ureter during the bypass surgery. She did not have swallowing deficits or any neurologic impairment, but her caloric intakes were insufficient.

The nasogastric tube malfunctioned and was replaced with a new one, using a metal guide wire; the patient coughed briefly during the replacement procedure. Afterwards, she reported high lumbar and retrothoracic pain on the right side, just above the nephrostomy. A control chest radiograph, ordered by the treating physician, showed that the feeding tube had been incorrectly placed into the posterior pleural space and had passed through the right bronchus and lower lobe of the lung (Figure 1A). No feeding had been started and no hemoptysis was present. Removal of the feeding tube led to a pneumothorax, which was drained (Figures 1B, 1C). The patient was monitored in the intensive care unit for 24 hours, without further complications.

(A) Chest radiograph showing a nasogastric tube with metal guide wire, positioned along the right bronchus and penetrating through the lower lobe into the pleural space in a 78-year-old woman. A right-side nephrostomy, implantable cardioverter defibrillator and poststernotomy wires are also visible. (B) Chest radiograph taken after removal of the tube showing a pneumothorax. (C) Chest radiograph taken after pleural drainage with a pleural pigtail catheter showing the resolved pneumothorax.

Incorrect placement of nasogastric tubes can lead to numerous complications, including bronchopleural fistula, pneumothorax and aspiration pneumonia.1 Other lesions of the nasopharyngeal, laryngeal, esophageal and airway structures may occur; however, the structure of the lung parenchyma is more prone to perforation.

Patients with suppressed cough or gag reflexes, or with impaired consciousness (e.g., critically ill patients) are at highest risk for incorrect placement of the nasogastric tube. Chest radiography is the gold standard for confirming appropriate placement of a nasogastric tube. If the feeding tube is blindly inserted, radiographic confirmation of correct placement is recommended before administration of medication or feeding.2 There should be no exceptions to this rule, because other methods (e.g., auscultation of air blow, examination of gastric aspirate and measurement of its pH) are unreliable.3

Competing interests: None declared.

This article has been peer reviewed.

The authors have obtained patient consent.

Chapter 10. Tubes and Attachments

A nasogastric (NG) tube is a flexible plastic tube inserted through the nostrils, down the nasopharynx, and into the stomach or the upper portion of the small intestine. Placement of NG tubes is always confirmed with an X-ray prior to use (Perry, Potter, & Ostendorf, 2014).

NG tubes are used to:

• Deliver nutrients to the patient via a feeding pump
• Remove gastric contents

An NG tube used for feeding should be labelled. The tube is used to feed patients who may have swallowing difficulties or require additional nutritional supplements. These tubes are narrower and smaller bored than a Salem sump or Levine tube.

An NG tube can also remove gastric content, either draining the stomach by gravity or by being connected to a suction pump. In these situations, the NG tube is used to prevent nausea, vomiting, or gastric distension, or to wash the stomach of toxins.

The NG tube is fastened to the patient using a nose clip, and is taped and pinned to the patient’s gown to prevent accidental removal of the tube and to prevent the tube from slipping from the stomach area into the lungs.

When working with people who have nasogastric tubes, remember the following care measures:

• Maintain and promote comfort. The tube constantly irritates the nasal mucosa, causing a great deal of discomfort. Ensure that the tube is securely anchored to the patient’s nose to prevent excess tube movement, and is pinned to the gown to avoid excessive pulling or dragging.
• Because one nostril is blocked, patients tend to mouth breathe. This causes dehydration of the nasal and oral mucosa, and patients will complain of thirst, but they are usually NPO (nil per os or nothing by mouth). Mouth care will help to relieve the dryness. This can include rinsing the mouth with cold water or mouthwash as long as the patient does not swallow. Some patients may be allowed to suck on ice chips.
• If the patient complains of abdominal pain, discomfort, or nausea, or begins to vomit, report it immediately. The drainage flow is probably obstructed and the tube will need to be irrigated.
• These patients should never be allowed to lie completely flat. Lying flat increases the patient’s risk of aspirating stomach contents. Patients with an NG tube are at risk for aspiration. The head of bed should always be raised 30 degrees or higher.

Checklist 78 outlines the steps for inserting a nasogastric tube.

Checklist 78: Inserting a Nasogastric tube

Perform hand hygiene. Check room for additional precautions. Introduce yourself to patient. Confirm patient ID using two patient identifiers (e.g., name and date of birth). Explain process to patient; offer analgesia, bathroom, etc. Listen and attend to patient cues. Ensure patient’s privacy and dignity. Assess ABCCS/suction/oxygen/safety. Apply principles of asepsis and safety. Check vital signs. Complete necessary focused assessments.
1. Perform hand hygiene and gather supplies.	This prevents the transmission of microorganisms. Gather supplies
2. Visually inspect condition of patient’s nasal and oral cavities.	Check for signs of infection or skin breakdown.
3. Assess for the best nostril before you begin. Do this by occluding one side and asking the patient to sniff. Ask the patient about previous injuries or history of a deviated septum.	If either nostril is equally suitable, select the nostril closest to the suction. Assess for most patent nostril
4. Palpate patient’s abdomen for distension, pain, and/or rigidity. Auscultate for bowel sounds.	Document assessment findings and determine appropriateness of NG tube insertion related to reason for insertion and patient’s physical assessment.
5. Assess patient’s level of consciousness and understanding of procedure.	Patient must be able to follow instructions related to NG insertion to allow for passage of tube through nasal and gastrointestinal tracts.
6. Check doctor’s orders for type of NG tube to be placed and reason for placement.	Check appropriate orders relevant to patient safety.
7. Check doctor’s orders to determine whether the NG tube is to be attached to suction or a drainage bag.	This should be commensurate with the reason for the NG tube.
8. Position patient sitting up at 45 to 90 degrees (unless contraindicated by the patient’s condition), with a pillow under the head and shoulders.	This allows the NG tube to pass more easily through the nasopharynx and into the stomach.
9. Raise bed to a comfortable working height.	This helps prevent biomechanical injury to the health care provider.
10. Agree on a signal the patient can use if they wish you to pause during the procedure.	This procedure can be anxiety-provoking and uncomfortable for many patients. Providing a means for the patient to communicate discomfort and a desire to pause during the procedure helps alleviate anxiety.
11. Place a towel on the patient’s chest and provide facial tissues and an emesis basin.	Nasal and oral secretions may be evident during the procedure.
12. Provide patient with drinking water and a straw if the patient is not fluid restricted.	Sipping water through a straw helps to initiate the swallowing reflex and facilitate passing of NG tube.
13. Stand on patient’s right side if you are right-handed and the left side if you are left-handed.	You will use your dominant hand to insert the tube.
14. Measure distance of the tube from The tip of the nose, to… The earlobe, to… The xiphoid process and then mark the tube at this point.	This determines the appropriate length of NG tube to be inserted. Measure from tip of nose to earlobe Measure from earlobe to xiphoid process
15. Lubricate NG tube tip according to your agency policy.	Tube may be lubricated internally using tap water or externally using water-soluble lubricating jelly. Agency policy varies and should be checked. Lubricate tip of tube as per agency policy Never use non-water-soluble lubricant (e.g., Vaseline), as it will not dissolve and may cause respiratory complications if it enters the lungs.
16. Apply clean non-sterile gloves.	Using gloves decreases the transfer of microorganisms. Apply clean non-sterile gloves
17. Curve 10 to 15 cm of the end of the NG tube around your gloved finger, and then release it.	Curling the NG tube around your finger helps it conform to the normal curve of the nasopharynx. Curl the NG tube around your finger
18. Have patient drop head forward and breathe through the mouth.	Dropping the head forward closes the trachea and opens the esophagus, which allows the NG tube to pass more easily through the nasopharynx and into the stomach.
19. Insert NG tube tip slowly into the patient’s nostril and advance it steadily, in a downward direction, along the bottom of the nasal passage, with the curved end pointing downward in the direction of the ear on the same side as the nostril.	This follows the natural anatomical alignment of the nasopharynx. Insert nasogastric tube slowly into patient’s nostril
20. You may feel slight resistance as you advance along the nasal passage. Twist the tube slightly, apply downward pressure, and continue trying to advance the tube. If significant resistance is felt, remove the tube and allow the patient to rest before trying again in the other nostril.	It is common for the patient to feel discomfort, and this may be expressed with light coughing and gagging. More aggressive coughing and gagging may indicate that the tube has entered the airways, in which case you should withdraw the NG tube. Advance the tube gently
21. If there is difficulty in passing the NG tube, you may ask the patient to sip water slowly through a straw unless oral fluids are contraindicated. If oral fluids are not allowed, ask the patient to try dry swallowing while you advance the tube.	If patient continues to gag or cough, check that the tube is not coiled in the back of the mouth, using a tongue blade and a flashlight to check the back of the mouth. If tube is coiled, withdraw the tube until only the tip of the tube is seen in the back of the mouth. Then try advancing the tube again while patient tries to swallow. Patient may sip water slowly through a straw
22. Continue to advance NG tube until you reach the mark/tape you had placed for measurement.	This ensures accurate placement.
23. Temporarily anchor the tube to patient’s cheek with a piece of tape until you can check for correct placement.	This prevents displacement of the NG tube while checking placement. Anchor tube
24. Verify tube placement according to agency policy. Colour-coded pH paper is usually used, as an initial and interim check, to confirm that acidic contents are present. Then an X-ray is taken to confirm placement prior to using NG tube for feeding.	The contents aspirated from the tube should be acidic with a pH <5. If the pH is more than 6, it may indicate the presence of respiratory fluids or small bowel content, and the tube should be removed. Verify tube placement using pH paper
25. Once the tube placement has been confirmed, mark (with a permanent marker) and record the length of tubing extending from the nose to the outer end of the tube.	This aids in timely recognition and identification of tube displacement or migration.
26. Secure the tube to the patient’s gown with a safety pin, allowing enough tube length for comfortable head movement.	This keeps the NG tube in place. Secure the tube to the patient’s gown with a safety pin
27. Document the procedure according to agency policy, and report any unexpected findings to the appropriate health care provider.	Timely and accurate documentation promotes patient safety.
Data source: ATI, 2015a; BCIT, 2015c; Berman & Snyder, 2016

Special considerations with NG tubes:

• Always assess correct placement of the NG tube prior to infusing any fluids or tube feeds as per agency policy. Check location of external markings on the tube and colour of the PH of fluid aspirated from the tube. Routine evaluation will ensure the correct placement of the tube and reduce the risk of aspiration. Do not instill air to test location of tube.
• Do not give the patient anything to eat or drink without knowing that the patient has passed a swallowing assessment.
• If changing the gown or repositioning the patient, take care not to pull on the NG tube. Remember to unpin the tube from the gown and repin the tube.
• If the NG tube falls out of the patient, it is not an emergency. But be sure to assess your patient. How are the ABCCS? Notify the RN in charge of the patient.
• A patient who appears to be in respiratory distress should be considered an emergency, and emergency procedures should be followed. Respiratory distress may present as coughing, choking, or reduced oxygen saturation.

Video 10.1

Removing an NG Tube

An NG tube should be removed if it is no longer required. The process of removal is usually very quick. Prior to removing an NG tube, verify physician orders. If the NG tube was ordered to remove gastric content, the physician’s order may state to “trial” clamping the tube for a number of hours to see if the patient tolerates its removal. During the trial, the patient should not experience any nausea, vomiting, or abdominal distension.

To review how to remove an NG tube, refer to Checklist 79.

Checklist 79: Removal of an NG Tube

Perform hand hygiene. Check room for additional precautions. Introduce yourself to patient. Confirm patient ID using two patient identifiers (e.g., name and date of birth). Explain process to patient; offer analgesia, bathroom, etc. Listen and attend to patient cues. Ensure patient’s privacy and dignity. Assess ABCCS/suction/oxygen/safety. Apply principles of asepsis and safety. Check vital signs. Complete necessary focused assessments.
1. Verify health care provider’s orders to remove NG tube.	An order is required to remove an NG tube.
2. Collect supplies.	Supplies include waterproof pads, 20 ml syringe, tissues, non-sterile gloves, and garbage bag.
3. Verify patient using two identifiers. Explain procedure to patient and place patient in high Fowler’s position.	Follow agency policy for proper patient identification.
4. Perform hand hygiene. Place waterproof pad on patient’s chest.	This reduces the transmission of microorganisms. Perform hand hygiene
5. Disconnect tube from feed if present.	This prevents risk of aspiration of tube feed. Disconnect tube from feed or suction
6. Remove tape or securement device from nose.	This allows for the tube to be easily removed. Remove tape or securement device from nose
7. Unclip NG tube from patient’s gown.	This allows for tube to be easily removed. Unclip NG tube from patient’s gown
8. Clear NG tube by inserting 10 to 20 ml of air into tube.	This prevents aspiration of tube feed falling out of tube. Insert 10 to 20 ml of air into NG tube
9. Instruct patient to take a deep breath and hold it.	This prevents aspiration; holding the breath closes the glottis.
10. Kink the NG tube near the naris and gently pull out tube in a swift, steady motion, wrapping it in your hand as it is being pulled out. Dispose of tube in garbage bag.	This prevents any residual feed from flowing out of tube upon removal. Pull out tube in a swift, steady motion Wrap tube in glove and dispose as per agency policy
11. Offer tissue or clean the nares for the patient and offer mouth care as required.	This clears the nares/nasal passages of any remaining secretions. Offer tissue or clean the nares for the patient
12. Remove gloves and place patient in a comfortable position. Assess patient’s level of comfort. Perform hand hygiene.	This promotes patient comfort and reduces the transmission of microorganisms. Hand hygiene with ABHR
13. Document procedure according to agency policy	Document removal of NG tube and patient response to the removal.
Data source: ATI, 2015a; BCIT, 2015b; Perry et al., 2014

1. You are inserting a nasogastric tube and the tube is not advancing. Explain your next steps, with rationale.
2. Your patient has a nasogastric tube and is requesting water because her throat feels dry. Describe your next actions.