The effectiveness of auscultatory, colorimetric capnometry and pH measurement methods to confirm placement of nasogastric tubes: A methodological study

Abstract

Aim: To determine the effectiveness of auscultatory, colorimetric capnometry and pH measurement methods for confirmation of correct nasogastric tube placement in critically ill patients.Background: Incorrect nasogastric tube placement causes serious complications.Design: This was a methodological and comparative study. Methods:The study sample consisted of 88 new insertions of nasogastric feeding tubes between April 2018-2019. Results from the 'auscultatory', 'pH' and 'colorimetric capnometry' methods were compared with the location of the nasogastric tube as determined through radiography. Descriptive statistics, Eta analysis and the Cohen kappa compliance test as well as sensitivity and specificity were conducted.Results: There was a weak agreement (26.3%) between the auscultation and radiological evaluation for confirming nasogastric tube placement. The pH measurement and colorimetric capnometry methods were not correlated with radiological evaluation. Stomach pH increased as patient age increased and use of the colorimetric capnometry method failed to confirm the oesophageal and duodenal location. The specificity of the auscultation was low, and both the specificity and sensitivity pH methods were low. Conclusion:It was determined that auscultation, measuring pH and colorimetric capnometry were unreliable methods for confirming placement of nasogastric tubes.It is recommended to confirm initial placement of the nasogastric tube with radiography and to develop effective and reliable non-radiological measurement methods that can be performed at the bedside.

Evolving Therapeutic Roles of Nasogastric Tubes: Current Concepts in Clinical Practice

“…Studies to measure the ETCO 2 and pH to determine the threshold values to potentially improve the positioning of NGT correctly are ongoing [ 21 ]. Taskiran et al [ 22 ] did a methodologic study to evaluate the effectiveness of auscultatory, pH measurement methods and calorimetric capnography for the confirmation of NGT placements [ 22 ]. It was determined that all three methods were unreliable to confirm the correct NGT placement; the authors recommended that initial placement of the NGT continues to be confirmed by radiography.…”