Evaluation of Airway Assessment Parameters: Hyomental Distance versus Ultrasound-guided Pretracheal Tissue Thickness as Predictors of Difficult Laryngoscopy

Abstract Background: Difficult airway remains a major cause of anesthesia-related morbidity and mortality despite advances in airway management. Conventional clinical predictors have limited predictive value. Airway ultrasound has emerged as a noninvasive tool that may improve preoperative airway assessment. Aim: The study aimed to evaluate the utility of ultrasonography as a preoperative assessment tool for predicting difficult airway and to compare its predictive accuracy with hyomental distance. Materials and Methods: This prospective observational study included 100 adult patients undergoing elective surgery under general anesthesia requiring endotracheal intubation. Preoperative airway assessment involved measurement of hyomental distance and ultrasonographic measurement of pretracheal soft-tissue thickness at the level of the vocal cords. After induction of anesthesia, direct laryngoscopy was performed and graded using the Cormack–Lehane classification. Results: The mean hyomental distance was significantly lower in patients with difficult laryngoscopy. Pretracheal soft-tissue thickness measured by ultrasound was significantly higher in this group ( P = 0.0001) and showed a stronger association with poor glottic visualization. Conclusion: Ultrasonographic measurement of pretracheal soft-tissue thickness is a reliable and superior predictor of difficult laryngoscopy and may enhance routine preoperative airway assessment and patient safety.