NG tubes are passed from the nose to the stomach. Depending on the material, they can stay between 2 to 6 weeks. However, they quite easily can fall out either being accidentally tugged at night or the tube might get caught. Due to this, they sometimes fall out within a week or two.
- Wide-bore NGT relieve pressure in the stomach (e.g. in bowel obstruction)
- Fine-bore NGT are used for feeding/nutrition, medication (and sometimes for decompression in bowel obstruction)
Pain & discomfort can occur from irritation of the nose, pharynx or oesophagus. There may be localised erosion or necrosis anywhere along its path. Gastric perforation is also a possibility. Wide-bore NGTs are more uncomfortable and have a higher risk of irritation and erosion.
With this in mind, there are strict rules on who can confirm an NG tube placement on imaging in all hospitals. It is vital that you review these policies. Other than the lungs, the tube could coil in the mouth/pharynx or be inserted into the duodenum. Basal skull fracture or facial trauma is a contraindication for insertion, as theoretically the NGT could perforate through the basal skull into the brain. There are a few case reports of this occurring.
Contraindications – confirmed or suspected basal skull fracture, facial trauma, patient refusal
Equipment for Insertion
- Gloves (non-sterile)
- NG tube (check size)
- Lubricating jelly
- A cup of water (& straw)
- Tape (fabric tape works very well)
- Drainage/collection bag
- Vomit bowl
- Syringe (larger one for wide bore NG insertion)
- pH strip
Before inserting, ensure you’ve checked whether an NGT is necessary. If placement is for feeding, it is very unlikely to be an urgent overnight job and it is likely to be safer to wait for the next day.
- Obtain consent
- Explain the procedure. Insertion is usually more successful when the patient knows that they need to swallow when they feel the tube hit the back of their throat
- Get patient in the correct position: sat upright with their head against a pillow. Do place a vomit bowl in front of them & give them the cup of water informing them you’ll advise them when to drink. It is helpful to have someone present who can assist you or support the patient.
- Wash hands and put gloves on
- Measure distance NG needs to be inserted: hold one end to tip of the nose → ear lobe → xiphisternum. Remember this measurement
- Ask the patient to take a sip of water and hold it in their mouth
- Cover the tip of the NG tube with lubricating jelly
- Examine the nostrils for deformities or things that may cause obstruction
- Insert the tube through one nostril – holding horizontally directing it backwards. If there is a lot of resistance gently adjust the angle of the tube trying to keep generally horizontal, alternatively try the other nostril. Don’t force the tube.
- When you feel the tube hit the back of the throat ask the patient to swallow some water
- Advance the tube as they swallow – stop at the length you have measured
- Tape in place (tape included in the pack or with fabric tape works very well – see picture)
- Attach the drainage bag if necessary
- Check if the tube is in position (if using the pH, ask a nurse to double-check with you!) and document – including the ease of insertion & number of attempts. Do leave the guidewire in place until position confirmed in case you need to x-ray.
Checking they’re in the right position
- Aspirate NG tube – check fluid pH. Check your local guidelines for cut-off pH values
- Chest x-ray (CXR) – if pH raised or no aspirate obtained. You’ll want to see the tip of NG tube on the x-ray. In most trusts, F1s cannot confirm NG tube placement on CXR. However, you should get used to reviewing the images for your learning but also to urgently remove the tube if you spot it is in an incorrect position.
Keeping an NG Tube in place
Be honest with your patient & relatives that these tubes frequently fall out. Bridles and mittens are sometimes used to reduce this risk.
Bridles – umbilical tape is inserted using two magnetic probes (the image below will explain what this means!). They should be used with consent in a patient that isn’t confused or agitated. An agitated or confused patient may forcibly remove the NGT and damage their nasal septum.
They’re great for patients in whom displacement occurs accidentally or where you want to minimise the risk of it getting displaced (technically difficult insertion/abnormal anatomy or intra-operative placement e.g. to protect an anastomosis).
Hand control mittens – soft, padded mittens which patients who have been pulling out essential lines can wear to prevent this happening further.
They are most often used in those who are very unwell (and therefore drowsy/confused), cognitively impaired or restless & agitated. If the patient is intermittently confused, ask for their consent to use them. However, often they lack capacity (due to their concurrent illness) and thus may be used in their best interests as per the Mental Capacity Act. Nevertheless, this type of restraint can be quite distressing and restricts their liberties and so Deprivation of Liberty Safeguard (DOLS) needs to be considered.
Clearly, these are complex decisions, thus it is essential to have the involvement of the multidisciplinary team, family and any next of kin. Your seniors should be the ones leading on these conversations.
Feeding via NG tube
Usually, the tube position is checked before every feed or administration of medication, if there are concerns it may have displaced (e.g. coughing, vomiting, suction) or if there are signs of respiratory distress.
For medication, ask the pharmacist to check what can be safely crushed or used through an NGT. Modified-release preparations cannot usually be crushed.
It is important to review how well patients are absorbing the feed. Poor absorption is evidenced by large volume aspirates from the NGT or vomiting. To address this, you can reduce the rate of feed or introduce motility agents (e.g. erythromycin or metoclopramide). The risk is that the patient may aspirate and this risk is higher in those with reflux or gastric stasis (which may make NG feeding less suitable). Ensure you discuss this with the gastroenterology, dietitian or nutrition teams.
If a patient is likely to require longer-term feeding, consider NJ (nasojejunal) or PEG (percutaneous endoscopic gastrostomy) feeding.
Further Reading & References
- Oxford Handbook for the Foundation Programme
- NGT Confirmation on CXR
- GeekyMedics – NGT placement
- Guide to Bridle Insertion
Written by Dr Nicola Conquest (GPST1)
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