There are certain procedures that we all love to do. Some people like intubations, some like lumbar punctures. Pretty much nobody likes inserting nasogastric tubes. I’ve spent many frustrated minutes, having performed the smoothest first pass intubation, wrestling with the wiggly piece of plastic known as the nasogastric tube. In this blog post I’m going to refresh our knowledge of how best to put them in, and offer some advice from Simon Walsh on another way…
Why are we putting them in in the first place?
Consider an NGT as a away of putting something in or a way of taking something out. Fine bore tubes are inserted as an alternative means of feeding sick or immature neonates with a poor suck/swallow reflex or those in whom oral feeding is contra-indicated (e.g. certain neurological disorders). In older children they may be used as an alternative means of hydration when you don’t want to use an IV.
They also allow the passage of insufflated air out of the stomach in intubated infants and and children. Neonates on nCPAP or Hi-Flow might be better served with an orogastric tube.
Finally they can be used as a diagnostic aid in cases of suspected choanal atresia or tracheo-oesophageal fistula.
What can go wrong?
A number of complications have been recorded in the literature including:-
- Local trauma
- The dreaded intracranial insertion in a child with a base of skull injury or abnormality
- Pneumonitis from enteral feed in the lungs
- Aspiration following tube dislodgement
- Feeding and absorption issues if the tube is in too far
Is it painful?
Although children are used to sticking things in their noses – fingers, beads, corn kernels – long plastic tubes might be a little more uncomfortable. What can we do to reduce the pain of insertion? A team, lead by Franz Babl, from the Royal Children’s Hospital in Melbourne, compared nebulized 2% lignocaine (4mg/kg) with a saline placebo. Whilst you might think that the local anaesthetic might reduce FLACC scores the mere act of putting a nebulizer on the face raised distress levels to the point that it was not worth the stress.
You could try oral sucrose in infants under one year of age but the evidence for benefit is equivocal.
What size tube do you need?
What length of tube do you need?
Most of us put in NGTs without fluoroscopic guidance so there needs to be some way to predict when the tip of the tube is in the right place. Most of the time we use surrogate external landmarks to extrapolate the length – the nose-ear-xiphoid process approach.
In neonates, measure from nares to ear to a point midway between xiphisternum and umbilicus.
Data supports that even this technique can lead to a variety of lengths with Beckstrand et al. finding a difference of up to 11.2cm in inter-rater measurements. So like any good tradie, measure twice and insert once.
And now to the tricky part…
There are certain patients that are going to be tricker than others – younger infants, those with active vomiting or abdominal distension and those with a decreased level of consciousness.
What do you need?
- The appropriately sized silastic nasogastric tube with guide wire
- Pre-cut pieces of hypoallergenic tape
- Sterile water, or a water-soluble lubricant, to aid insertion
- 10ml syringe
- pH test strips
Like most things in paediatrics, things are made much, much easier with a skilled helper. In our ED the nursing staff are the masters of this procedure, I am but an apprentice.
- Wash your hands.
- Lubricate the first few centimetres of the tube with water or a water-soluble lubricant.
- Insert the tube into the chosen nostril (Did you know we have a nostril preference?) along the floor of the nose, aiming towards the ear, not the top of the head.
- Let the child sip at water through a straw (if old enough) or suck in a dummy, to ease passage.
- Slowly advance the tube until the point you have marked is at the level of the nostril. If it starts to curl up and come out of their mouth then withdraw the tube, take a breath, and start again.
- Secure the tape carefully with tape.
- Check for the correct positioning of the tube (see below).
- Remove the guidewire.
Sometimes it is not that easy though, as Simon Walsh points out…
Nasogastric (NG) tube insertion is a routine occurrence in all Emergency Departments, both adult and paediatric. It is a procedure that we all do in our early medical careers, and less so as we progress.
NG tube insertion is a procedure I am very familiar with, mainly in adults, in ED, ICU and Retrieval.
Paediatric NG insertion was never a regular procedure that I would do, because the wonderful nursing staff are normally very happy to do it for us, and might ask for assistance on the tricky ones (which is not that often).
My youngest daughter, Zoë, is 2 and a half. She has recently been diagnosed with a genetic and epileptic encephalopathy, CDKL5, a disease I had never heard of before. A couple of the many issues that are associated with it are epilepsy requiring anti-epileptic drugs and poor feeding. Hence, she has had an NG tube for some time now.
Unfortunately, Zoë’s NG insertions are really difficult. Initially, not wanting to be doing them to my own child, we were making impromptu visits to the paediatric ward and getting them put in by experienced nurses and medical staff. Having watched the multiple failed attempts and the distress, I started doing them myself, and they were difficult.
During a difficult insertion, I tried a technique that worked first attempt.
The technique uses sustained jet insufflation, with an empty 10ml syringe attached to the end of the NG tube, applied once resistance is felt while advancing within the nasal cavity. For me this has turned extremely difficult and drawn out insertions into quick and tearless procedures.
Obviously this is not required for all patients’ NG insertions, but may be considered for those difficult ones.
I was unable to find this technique documented in the literature, so thought I would share.
Simon Walsh FACEM
So, you’ve got it in. How do you know it is in the right place?
You could go for the old fashioned approach – listening – but this is not as sensitive as you might think. In 2012 the Child Health Patient Safety Organisation recommended that we discontinue this method of confirmation after a study of 2000 NGT insertions found that 1.3% to 2.4% were outside the GI tract. An earlier American study reported an error rate that is much more serious – around 43.5% Of these, 20% caused pulmonary complications. Whilst most pulmonary insertions are picked up prior to use, failure to recognise placement in the right main stem bronchus can have catastrophic consequences.
A safer approach than just listening is to aspirate what is hopefully gastric contents from the tube using an enteral syringe and check the pH. It should be be less than 4. This is not a fool proof method either. Gilbertson et al. tested the pH of 4330 aspirates and found that 30.9% had a pH that was higher than 4. 10 of these 1339 tubes were found to be misplaced on radiograph. They suggest a cut off of ≤ 5 should be used as the lowest pH in a tracheo-bronchial aspirate was 6. True pH testing is much more reliable than the blue-red litmus test strips that are found in many departments.
But what can you do if you can’t aspirate anything? Try rolling the patient onto the side or advancing the tube a centimetre or so in the hope that one of the ports is now in a pool of stomach contents. Alternatively you can insert a small amount of air down the NGT to blow it away from the stomach wall.
The gold standard is, of course, radiography. This is not a practical bedside solution for most. Especially for parents who often replace long term enteral feeding tubes at home rather than go to hospital.
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