Preoperative airway mapping with ultrasound: Bridging the gap in predicting difficult intubation

Abstract

Background: Anticipating difficult intubation remains a cornerstone of safe airway management. Traditional assessment methods such as Mallampati score and thyromental distance have limited predictive accuracy. Recent evidence suggests that point-of-care ultrasound (POCUS) can offer quantitative, non-invasive insight into airway anatomy, potentially improving pre-intubation risk stratification. Materials and Methods: This prospective observational study was conducted in the Department of Radiology, JIS School of Medical Sciences and Research, Howrah, West Bengal, from December 2021 to November 2022. Adult patients scheduled for elective surgery under general anesthesia were assessed preoperatively using both conventional clinical parameters and airway ultrasound. Key ultrasonographic measurements included anterior neck soft tissue thickness at the level of the hyoid bone and the vocal cords, as well as hyomental distance in neutral and extended neck positions. The primary outcome was correlation between ultrasound parameters and Cormack-Lehane grade during laryngoscopy. Receiver operating characteristic (ROC) curves were constructed to assess predictive validity. Results: Out of 120 patients assessed, 24 (20%) were classified as having difficult intubation (Cormack-Lehane grades III/IV). Increased pretracheal soft tissue thickness at the vocal cord level (>0.30 cm) and reduced hyomental distance in extension (<4.2 cm) were significantly associated with difficult laryngoscopy (p<0.01). The area under the ROC curve (AUC) for pretracheal thickness was 0.84, indicating high predictive value. Conclusion: Ultrasound measurements of airway structures offer valuable, reproducible predictors of difficult intubation. Integration of sonographic assessment into routine pre-anesthetic evaluation may enhance airway safety.