Study finds device plays key role in reducing NG tube misplacement

A study has found that a fibre-optic electronic device can play a key role in reducing incidents of nasogastric (NG) tube misplacement - the fourth most common cause of never events in hospitals in England, according to new data released by the NHS.

Published in BMJ Nutrition, Prevention & Health, the study highlights how NGPod, a device designed to help confirm the correct placement of the tubes used by NHS clinicians to administer nutrition, hydration and medication to patients, is significantly more likely to deliver a ‘definite result’ than current procedures, reducing the likelihood of never events occurring and avoiding clinically significant delays to patient treatment.

Every year, more than a million NG tubes are used by NHS clinicians, equivalent to at least 2,700 every day. However, the ‘blind’ process of inserting the tube into a patient’s stomach is fraught with challenge, with data showing that 1-3% of all insertions are incorrectly placed into the lungs, which can have catastrophic consequences, causing serious injury and even death, if not spotted before treatment begins. The NHS classifies such incidents as never events.

While fatalities are relatively rare, new data recently published by the NHS shows that incidents of misplaced NG tubes where feeding had already been accounted for 15% of all never events recorded by hospitals in England in April 2023. Between April 2022 and March 2023, the same scenario accounted for 31 out of 384 serious incidents – equivalent to 8% of all never events recorded by hospitals in England that year. 

Further NHS data also suggests that such incidents are becoming more common; in the five-year period between 1st April 2018 and 31st March 2023, 150 never events were recorded by hospitals in England due to feeds being delivered through wrongly inserted NG tubes – a 32% increase on the number (114) recorded over the previous five-year period between 2012-17. Separate to that, an FOI request exploring data between 2017 and 2022 revealed that, while half of NHS Trusts in England reported zero incidents over this five-year period, this type of never event happened up to seven times in some NHS Trusts.

Existing measures to check that NG tubes have been correctly placed in the stomach – including a first line check of obtaining aspirate for pH testing and second line checks of x-ray or subjective clinical assessment – have variable reliability and lead to feed delays for patients, experts, such as nutrition charity BAPEN and the Healthcare Safety Investigations Branch (HSIB) to call for an alternative.

In the BMJ study, the authors reported that when using pH strips, the necessary aspirate couldn’t be obtained from the patient in 46% of cases, meaning an x-ray would be necessary. Even when aspirate can be obtained, a range of factors including inadequate lighting, poor eyesight, or inexperience mean that 12-30% of pH strips are misread. The pressure of correctly interpreting pH strips in these circumstances is a cause of anxiety in 30%-50% of clinicians and may be leading to more x-rays than would otherwise be necessary.

John Carrington, CEO of NGPod, which produces all of its devices in Cheshire, said: “NGPod is already making a positive difference in ten NHS hospitals and this latest study serves to demonstrate the transformative impact it could have if introduced at scale in hospitals across the UK, providing clinicians with an easy-to-use, quick and, crucially, reliable method of confirming the placement of the thousands of NG tubes used every day.

“It builds on previous research which shows that, when compared with the first-line check of aspirate pH tests, NGPod not only delivers a definite result more often, it also does it more quickly, with feeding tubes able to be used within two minutes in more than 90% of cases.

“What’s more, a cost-analysis has shown that NGPod lowers the cost of healthcare when compared with current methods – meaning it’s not only more effective and better for patients, but it’s also more cost-effective at a time when cost pressures on the NHS have never been greater.”

Some 28.5% of NG tube patients are currently sent to x-ray and while this is the only approved second-line method of checking for correct placement, studies show that half of patients sent for x-ray experience clinically significant delays (an average of 12 hours) to nutrition or drug treatment, which can have a detrimental impact on health. Most importantly, latest NHS data shows that the majority (55%) of NG tube related never events are caused by misinterpreted x-rays.

This latest clinical trial, conducted on 154 adult patients across three NHS secondary care sites, compared the performance of NGPod – which comprises a handheld electronic device and a fibre-optic sensor that is inserted into the patient’s feeding tube and doesn’t require aspirate – against the currently used procedure of testing gastric aspirate with pH universal indicator paper and visual comparison to a colour chart. It found:

NGPod is statistically more likely to deliver a ‘definite result’ than traditional aspirate pH tests, with 93.5% of NGPod tests achieving a pH result (positive or negative) compared to 83.9% of aspirate pH tests

When performing initial tests, immediately after tube placement, NGPod can reduce the need for x-rays or subjective clinical assessments by 61% of patients

When performing initial and repeat tests, NGPod can reduce the need for second line testing – x-ray or subjective clinical assessment – by 21.2%, which can reduce feeding delays

NGPod is as accurate as aspirate pH strip testing and able to deliver a result when it is not possible to obtain aspirate

Commenting on the findings, Tracy Earley, consultant nutrition nurse at Royal Preston Hospital who led the clinical study, said: “There have and continue to be nasogastric tube never events in hospitals in England when the use of misplaced NG Tubes have contributed to severe illness or even death. A number of NHS and clinician group reports have highlighted the need for a more reliable first-line method of nasogastric tube confirmation to replace the current procedure of testing gastric aspirate with pH universal indicator paper.

“The results from this study demonstrate that the adoption of NGPod could transform NG tube placement checks, providing a quick and reliable response to help clinicians decide whether it’s safe for the patient to feed or not.

“The current method of correctly interpreting a pH test is often challenging for clinicians. NGPod removes that pressure, reducing the risk of misreading aspirate pH tests and decreasing the need for x-rays by providing a definitive yes-no answer. The result is reduced risk, improved safety and fewer x-rays, meaning patients can access nutrition and medication more quickly. It also has the potential to reduce never events that are associated with NG tube misplacement.”