New Meridian challenge: NG tube positioning

Posted on 11 November 2020 (Permalink)

Our Meridian Innovation Exchange has published a call for solutions to consistently confirm the placement of an nasogastric tube. 

Nasogastric (NG) tubes sit in a patient’s stomach and are used for administering supplementary feeds and medicines, when a patient is unable to take them orally. They are life saving devices.

When inserting an NG tube, it is possible to pass it into a patient’s respiratory tract instead of their stomach. It is also possible for an NG tube, which is passed correctly into a patient’s stomach, to migrate from the stomach into the respiratory tract. This can happen when a patient vomits or coughs excessively.

When using NG tubes, nurses aspirate the NG tube using a syringe they attach to it. Any fluid they obtain is then pH tested. If that pH test = <5.5 then national guidelines state this is likely to be acidic stomach contents and therefore the NG tube is safe to use. If the pH result is >6.0 then it is possible the NG tube is in the respiratory tract.

There have been many serious incidents across the UK where patients have died / been seriously harmed after NG tubes have been used whilst they are incorrectly placed in a patients respiratory tract. This has been the subject of National Patient Safety Agency (NPSA) alerts and there are guidelines from the National Institute for Health and Clinical Excellence (NICE) that govern how NG tube placement should be confirmed.

Despite NPSA alerts and NICE guidelines, these serious incidents are still occurring. The reasons for this are:

  • pH testing relies on colour interpretation by a human being. Each human has differing ability to see colour differences. This perception can also be affected by tiredness and light levels at the patient’s bedside (especially at night).
  • Some patients need to take antacids which raises the pH of their stomach contents. This can render pH testing useless.
  • The only alternative to pH testing is sending the patient for a chest x-ray. The problem with this is that the position of an NG tube may need to be confirmed numerous times a day, every day. Due to radiation exposure, it is not possible for patients to have a chest x-ray each time the NG tube is used.
  • A pH result can be affected by other substances present e.g. the pH of medicines or feeds.

This problem affects all patients requiring feeding via NG tubes, neonates, children, young people, adults, patients with learning difficulties and patients with mental health problems.

What is needed?

We need a hand held device that is able to consistently confirm the placement of an NG tube. This device needs to:

  • Address the drawbacks of pH testing.
  • Be portable and light to be used at the bedside.
  • Be easy to use.
  • Be quick to use.
  • Show results that are easy to interpret i.e. it must be difficult interpret to results incorrectly even when tired, busy, working under pressure etc. They must also be usable to a large number of nursing staff rather than requiring expertise.
  • Be usable during the day and at night when wards are dimly lit.
  • Be quiet to minimise disturbance to patients.
  • Minimise the need for chest x-rays.
  • Be inexpensive and therefore scalable across many wards in a hospital and subsequently across the NHS.
  • Be cleanable to comply with infection control processes.

All innovations will be reviewed by Karl Emms Lead Nurse for Patient Safety at the Birmingham Children's Hospital.  He is looking forward to reviewing any ideas or innovations and is keen to give feedback and co collaborate along with his clinical colleagues.  

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