To Örebro University

BACKGROUND: Blind insertion of nasogastric tubes is performed for several reasons: Nutrition and medication administration, gastric aspiration/decompression, and other, diagnostic reasons. Accidental intraesophageal and intestinal placement is common, and increases the risk of serious complications. Therefore, accurate determination of the internal length of the nasogastric tube prior to placement is considered a prerequisite for achieving correct gastric positioning.

OBJECTIVES: To identify, assess and summarize the evidence on the accuracy of methods for determining the internal length of a nasogastric tube in adults.

METHODS: Cochrane Library, EMBASE, PubMed, CINAHL, and Web of Science were searched up to January 31, 2022. Studies were eligible when reporting data on the accuracy of methods for determining internal nasogastric tube length in adults. Study selection, risk-of-bias assessment, and data extraction were performed independently by two investigators. Risk-of-bias was assessed using the Cochrane Risk-of-Bias Tool and the JBI Critical Appraisal Checklist for Cross Sectional Studies. A narrative synthesis of the results was then conducted.

RESULTS: Twelve papers were included in this review. All studies were observational, cross-sectional in nature, except for one RCT. Ten methods for determining the internal length of a nasogastric tube were described. Correctly positioned NG tubes ranged from 13% to 99%. Results showed that the nose-earlobe-xiphoid (NEX) distance + 10 cm (M = 59.9 - 60.7 cm) and (NEX x 0.38696) + 30.37 + 6 cm (M = 56.6 - 56.7 cm) could potentially result in accuracy as high as 97.4 and 99.0%, respectively.

CONCLUSIONS: Current data do not provide conclusive evidence of 100% accuracy in finding a correctly placed nasogastric tube when using a method for determining the internal length. Blind placement, using any of the documented methods, cannot be considered safe without additional verification of tube tip positioning. Furthermore, using any of these ten methods does not reduce the risk of pulmonary intubation.