Submental Ultrasound Is Effective in Predicting Difficult Mask Ventilation but Not in Difficult Laryngoscopy

The goal of this study was to determine the utility of submental ultrasound parameters in distinguishing difficult airway management from easy airway management. Forty-one adult patients who underwent elective surgery under general anesthesia with endotracheal intubation from March to December 2018 were included. We used submental ultrasound to measure tongue base thickness (TBT) in the midsagittal plane and the distance between lingual arteries (DLA) in the transverse dimension. The primary outcome was difficult laryngoscopy, and the secondary outcome was difficult mask ventilation. Receiver operating characteristic curve analysis and logistic regression revealed no correlation between difficult laryngoscopy and SMUS measurements. Nevertheless, patients with difficult mask ventilation had significantly higher TBT (p = 0.009) and longer DLA (p = 0.010). After adjustment of confounding factors, increased TBT (>69.6 mm) was the sole independent predictor of difficult mask ventilation. The results indicated that SMUS is effective in predicting difficult mask ventilation but not difficult laryngoscopy.