X-ray checks of NG tube position: a case for guided tube placement

Abstract

Objectives: Checking nasogastric (NG) tube position by X-ray is too late to prevent 1.5% of blind tube placements entering the lung and results in delays to feeding and drugs. We audit the safety of the tube position and delay incurred by X-ray. Methods: From Radiology reports, we determined whether tube position was safe for feeding, factors associated with an X-ray request and the time delay from X-ray request to that report. For tubes misplaced into the lung, the distance from the carina to tube tip was measured and compared with that from published records of guided tube placement. Results: From 1 July 2019 to 30 June 2020, 1934 X-rays were done to check NG tube position in 891 patients. Gastric placement was confirmed in 85% but, because of tube proximity to the oesophagus, only 73% were deemed safe to feed. The 2.2% of tubes reported to be in the lung were a median of 18 cm beyond the carina compared to 12 cm and 0 cm for electromagnetic and direct vision methods of guided placement. X-ray checks delayed feed and drug treatment by >2 h in 51% of placements and 33% of patients required >3 X-rays during their enteral episode. Conclusion: X-ray checks are common and detect a high percentage of unsafe tube placements, leading to repeated X-ray and delayed delivery of drugs and nutrition. Interpretation can be difficult even when following standard national criteria and post-placement X-ray cannot prevent deep lung placement. Guided or combined methods of confirming tube placement should be investigated. Advances in knowledge: Reports included 27.5% of placements as unsafe, 2.2% in the lung at a median depth of 18 cm beyond the carina and too late to prevent 7 pneumothoraces. X-rays were repeated >3 times in 33% of patients over their enteral course and we are associated with clinically significant delays to drug treatment (and nutrition) in 51%; combined methods of tube confirmation or guided placement may be safer and more efficient.