Applying Submental Ultrasound as a Screening Tool for Nasogastric Tube Removal Indication: A Pilot Study with Real-world Application

PURPOSE: Nasogastric tube (NGT) usage is common among inpatients. However, there is a lack of a convenient and objective tool for assessing a patient's swallowing function for NGT removal. The feasibility of using submental ultrasound for making decisions regarding NGT removal remains unclear.

MATERIALS AND METHODS: This pilot study included patients with NGTs who underwent submental ultrasound examination for NGT removal from March 2023 to December 2025. Patients were divided into derivation and validation cohorts by different examiners. We first measured the resting mandible-hyoid distance and shortest distance when swallowing and then calculated the maximum hyoid bone displacement.

RESULTS: In the derivation cohort, the maximum displacement was shorter in the NGT group (n = 31) than in the control group (n = 27) (1.26 vs. 1.83 cm, p ≤ 0.001), and the displacement was shorter in the "NGT not removed" subgroup (NG-NR, n = 21) than in the "NGT removed" subgroup (NG-R, n = 10) (1.09 vs. 1.63 cm, p = 0.006). In the validation cohort, the displacement was shorter in the NG-NR subgroup (n = 18) than in the NG-R subgroup (n = 6) (1.36 vs. 1.89 cm, p ≤ 0.001). In the derivation cohort, the displacement showed an AUROC of 0.805 for distinguishing between the NG-NR and NG-R subgroups. A cut-off value of 1.32 cm yielded a sensitivity of 80.0% and a specificity of 81.0%. In the validation cohort, the AUROC was 0.836. In the age- and sex-matched validation cohort, the AUROC was 0.831. The interrater consistency was good.

CONCLUSION: Given its good discriminatory performance with regard to NG-R patient identification, interrater consistency, and convenience, submental ultrasound might be an effective screening tool for identifying suitable postacute NGT patients to start swallowing training before NGT removal.