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Nasogastric tube: insertion and checking its position

  • Procedure

The tube goes through the nose into the stomach; its position is confirmed before use, because a tube in the airway can kill.

Updated

What it is

A nasogastric tube is a flexible tube that enters through a nostril, passes down the pharynx and oesophagus and ends in the stomach. It is used to decompress the stomach (bowel obstruction, ileus) or to give feeds and medicines to someone who cannot swallow safely. Insertion is a clean, «blind» procedure: you cannot see where the tube goes. The biggest risk is that it enters the trachea. So the position is confirmed by X-ray before first use, the external length is marked, and it is checked before every use. Listening while injecting air (the «whoosh test») is not reliable and should no longer be used.

Indications

  • Decompressing the stomach in bowel obstruction, ileus or gastric atony.
  • Feeds or medicines through a working gut when the patient cannot swallow safely (for example, after a stroke).
  • Emptying the stomach to reduce the risk of aspiration.
  • Lavage or sampling of gastric contents, and removal of ingested toxins on order.
  • Bowel rest.

Contraindications and precautions

  • Absolute contraindication: major facial trauma or suspected basal skull fracture (risk of entering the skull).
  • Absolute contraindication: recent nasal, throat or oesophageal surgery, or oesophageal obstruction.
  • Caution: oesophageal trauma (caustics), clotting disorders or anticoagulation, oesophageal varices or strictures, previous bariatric surgery.
  • A tube placed by the surgeon after gastrointestinal surgery is never repositioned: if it comes out, the surgeon is told.
  • In an unconscious patient, check the gag reflex before starting.

Equipment

  • A tube of the ordered size: for decompression usually 14 to 16 Fr (double lumen); for feeding 8 to 12 Fr (softer).
  • Water-soluble lubricant, clean gloves, a towel or pad and tissues.
  • A cup of water and a straw (if the patient can swallow), a penlight and an emesis basin.
  • A syringe to aspirate, pH strips for human aspirate and a marker or tape.
  • A securement device or hypoallergenic tape; suction equipment if ordered.

Step by step (and why)

  1. Check the order, identify the patient and explain you will ask them to swallow at the throat — swallowing opens the oesophagus and eases gagging.
  2. Sit them in high Fowler's (at least 30°) with the head neutral — gravity and posture help the tube into the oesophagus.
  3. Inspect the nostrils and choose the more patent one — a blocked nostril means more trauma and bleeding.
  4. Measure nose-earlobe-xiphoid and mark the tube — it tells you how far to insert to reach the stomach.
  5. Lubricate the tip and insert it back along the nasal floor; if it resists, rotate gently and do not force — forcing causes bleeding and injury.
  6. At the oropharynx, ask them to bend the head forward and sip water as you advance — flexion closes the airway and guides the tube.
  7. If there is severe coughing, cyanosis or falling saturation, pull back until they breathe well — these suggest the tube is in the airway.
  8. At the mark, secure the tube without pressing on the nostril — pressure causes nostril injuries.
  9. Confirm position by X-ray before first use; aspirate pH is supporting — listening to injected air is not reliable.
  10. Record the marked external length and check it every 4 hours and before each use — a change suggests the tube has moved.

Complications

  • Discomfort, sinusitis or nosebleed: the most common; they usually settle when the tube is removed.
  • Placement in the trachea or lung: pneumothorax, aspiration, pneumonia and even death if used without checking.
  • Pressure injury of the nostril and erosion of the gastric lining with prolonged suction.
  • Oesophageal perforation: neck or chest pain, difficulty swallowing, breathlessness, subcutaneous emphysema or vomiting blood.
  • Passage into the skull through a basal skull fracture (rare and serious).

Next step: when to call for help

  • Breathing difficulty during or after insertion is an emergency: remove the tube and call for help at once.
  • Do not use the tube, and report, if the X-ray does not confirm the stomach or the external length has changed.
  • Report if you cannot pass it after two gentle attempts, if a nosebleed will not stop or if there is chest pain.
  • If respiratory symptoms suggest aspiration, stop feeds and medicines and report.

Test yourself

Think of the answer, then tap the question to see it.

How is the length of nasogastric tube to insert estimated in an adult?

By measuring from the tip of the nose to the earlobe and then to the xiphoid process (the NEX method), and marking that point on the tube.

What is the reference method to confirm tube position before first use?

An X-ray. Aspirate pH of 5.5 or less is a supporting test, but feeds and some medicines change it.

Is listening over the epigastrium while injecting air through the tube reliable?

No. The «whoosh test» and the look of the aspirate are unreliable for confirming position and should no longer be used.

What do you do if the patient coughs hard or turns cyanotic while the tube is advanced?

Pull the tube back until breathing settles, because it has probably entered the airway; if the difficulty persists, call for urgent help.

When is a nasal tube contraindicated?

In major facial trauma, suspected basal skull fracture, recent nasal, throat or oesophageal surgery, or oesophageal obstruction.

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Educational content for students; it does not replace your institution's protocols, supervised clinical training or a prescriber's order. Dose-calculation examples use made-up numbers: they are educational, not a clinical order.

Sources: Nursing Advanced Skills, 5.2: Basic Concepts (Insert Nasogastric and Feeding Tubes) (Open RN, Chippewa Valley Technical College (via LibreTexts), 2023); Nursing Advanced Skills, 5.4: Checklist - Insert a Nasogastric Tube (Open RN, Chippewa Valley Technical College (via LibreTexts), 2023); Nursing Skills, 7.2: Basic Concepts of Enteral Tubes (Open RN, Chippewa Valley Technical College (via LibreTexts), 2021).

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