To Örebro University

BACKGROUND: Several studies have shown that the nose-earlobe-xiphoid distance (NEX) is inadequate to estimate the insertion length of nasogastric tubes. An alternative approach tested in these studies, which leads to > 90% well-placed nasogastric tubes, used a corrected calculation of the NEX: (NEX × 0.38696) + 30.37. The primary aim of this study was to determine whether using the corrected NEX was more successful than the NEX in determining the insertion length. The secondary aim was to investigate the likelihood to successfully obtain gastric aspirate.

METHODS: Adult patients in a general hospital (N = 215) needing a nasogastric tube were randomized to the control (NEX) or intervention group (corrected NEX). Tip positioning was verified using X-ray. Correct tip positioning was defined as between 3 and 10 cm under the lower esophageal sphincter (LES).

RESULTS: In >20% of all patients, both methods underestimated the required tube length for correct positioning. The NEX showed an overestimation (17.2%) of the insertion length (>10 cm under the LES) compared with the corrected NEX (4.8%). There was no difference (P = 0.938) between the 2 groups in obtaining gastric aspirate (55.6% vs 56%). However, correct tip positioning resulted in a fourfold increase of obtaining gastric aspirate.

CONCLUSIONS: Both methods resulted in a high risk of incorrectly placed tubes due to malposition of the tip near the LES or distal esophagus. This may increase the risk of reflux and pulmonary aspiration. Based on these results, the development of more reliable methods requires consideration.