A novel enzymatic means to confirm correct and safe nasogastric tube placement

Lead Research Organisation: Imperial College London

Abstract

At least 1 million nasogastric feeding tubes are used by the NHS every year. Tube misplacements can and do have disastrous consequences, including death (National Patient Safety Agency data 2003-10). Existing methods to verify tube placements, including standard pH testing and the gold-standard chest X-rays, have major drawbacks in cost, usability or safety. We have a new enzymatic test to verify correct tube placement, that our pilot study show to be reliable and accurate, while low cost, simple and requiring no extra user training. The new test has great potential to translate into clinical practice. This project will refine the biochemistry and design of the test to provide a new diagnostic product into the NHS supply chain. It will carry out a clinical trial to further validate the technical performance of the test. Data on cost-effectiveness, clinical utility, clinical pathways and mitigation of barriers will be generated to assess the impact of its commercialisation and promote its adoption by the NHS.

Technical Summary

At least 1 million nasogastric feeding tubes are used by the NHS every year. Tube misplacements can and do have disastrous consequences, including death (National Patient Safety Agency data 2003-10). Existing methods to verify tube placements, including standard pH testing and the gold-standard chest X-rays, have major drawbacks in cost, usability or safety. We have a new enzymatic test to verify correct tube placement, that our pilot study show to be reliable and accurate, while low cost, simple and requiring no extra user training. The new test has great potential to translate into clinical practice. This project will refine the biochemistry and design of the test to provide a new diagnostic product into the NHS supply chain. It will carry out a clinical trial to further validate the technical performance of the test. Data on cost-effectiveness, clinical utility, clinical pathways and mitigation of barriers will be generated to assess the impact of its commercialisation and promote its adoption by the NHS.
 
Title novel enzyme based pH strips 
Description In collaboration with Scottish SME Ingenza, we are developing a novel pH strips for testing the pH of aspirates from nasogastric feeding tubes. The pH value then provides the basis for feeding, that is, if the pH is low, indicating acidity which is associated with stomach fluids. About 6 million pH strips are being used per year in the NHS alone. The existing strips are however not sensitive especially when patients are under feeding or medication. The new strips, by incorporating lipase, are capable of far better sensitivity. Since a higher pH would prompt the patient to be sent for a chest x-ray confirmation of tube locations, the new strips would reduce the use of chest x-rays as well as the financial costs, the administrative burden and radiation risks that come with it. 
Type Diagnostic Tool - Non-Imaging
Current Stage Of Development Late clinical evaluation
Year Development Stage Completed 2018
Development Status Actively seeking support
Clinical Trial? Yes
Impact We are carrying out a trial which has recruited 300+ patients from 10 NHS sites. We identified lower sensitivity in the existing pH strips compare to the literature, which suggested even higher number of chest x-rays are probably being requested as a result of the existing first line pH test lacking sensitivity. The new strip outperforms the existing strips by a margin of 20%, potentially reducing up to 40% of the chest x-ray request due to a higher pH. We published papers debating the selection of pH cut-offs, used human factor studies to inform the development of pH strips, leading to a potentially higher usable, and safer product. This product is in the process of being CE marked. We are discussing adoption with Imperial and Oxford AHSNs. We anticipate the adoption of this product would improve existing clinical practice, leading to safer feeding and better use of NHS resources. 
URL http://www.isrctn.com/ISRCTN11170249