Accuracy of interpretation of nasogastric tube position on chest radiographs by diagnostic radiographers: A multi-case, multi-reader study

Introduction

Feeding via a misplaced nasogastric tube (NGT) is a common but preventable cause of patient harm. The aim of this study was to determine the accuracy of diagnostic radiographers’ assessment of NGT position on chest radiographs (CXRs) and safe-to-feed decisions.

Methods

A multi-case, multi-reader study was conducted using an online image interpretation platform. A test bank consisting of 15 CXRs with an NGT in-situ was created. Diagnostic radiographers without formal qualifications in CXR interpretation were recruited via two international conferences. Participants placed an electronic marker on each CXR to identify the location of the tip of the NGT and indicated whether or not they believed that the tube was safely positioned.

Results

68 participants were recruited. Each participant reviewed 15 CXRs, providing 1020 unique image assessments. 76 % (n = 778/1020) image assessments were completely correct (both the position of the tip of the NGT was accurately located and an appropriate safe-to-use decision made). In 5 % (n = 56/1020) of cases the NGT was safely positioned and the location of the tip was correctly identified by the participant but the tube was erroneously determined to be unsafe for feeding. In a further 6 % (n = 59/1020) of cases the participant correctly located the tip of an NGT in an unsafe position but indicated that the tube was safe to use. Participants failed to correctly identify the tip of the NGT in the remaining 12 % (n = 127/1020) of cases.

Conclusion

Consistent with previous studies involving other staff groups, diagnostic radiographers without formal qualification in CXR interpretation can assess NGT positioning on radiographs with moderate accuracy but require further training, including strategies for the identification of poorly-visualised tube tips, to achieve the 100 % accuracy necessary for this safety-critical task.

Implications for practice

A bespoke training programme which includes teaching on image quality, tube tip identification and assessment of tube positioning using the National Patient Safety Agency (NPSA) four criteria, should be delivered prior to implementation of a radiographer-led NGT CXR evaluation service.