Usage of airway ultrasound as an assessment and prediction tool of a difficult airway management

Airway assessment is important in emergency airway management. A difficult airway can lead to life-threatening complications. A perfect airway assessment tool does not exist and unanticipated difficulty will remain unforeseen. Current bedside clinical predictors of the difficult airway are unreliable but airway ultrasound can be used as an adjunct to predict difficult laryngoscopy. We report a case of a 60-year-old man presenting to the emergency department with shortness of breath, hoarseness of voice and stridor. Airway ultrasound revealed a large laryngeal mass narrowing the upper airway, extending to bilateral vocal cords with heterogenous echogenicity. In view of impending complete upper airway obstruction, acute respiratory distress and airway ultrasound findings, urgent emergency tracheostomy was chosen as definitive airway over endotracheal intubation or surgical cricothyroidotomy. Point of care ultrasound (POCUS) was used to evaluate this patient with severe upper airway obstruction. A laryngeal mass was detected by ultrasound and this pointed towards the presence of a difficult airway. POCUS was a good non-invasive tool used for airway assessment in this uncooperative and unstable patient. Ultrasound predictors of the difficult airway include the inability to visualize the hyoid bone, short hyomental distance ratio, high pretracheal anterior neck thickness and large tongue size. Besides airway assessment, ultrasound can also help to predict endotracheal tube size, confirm intubation and guide emergency airway procedures such as cricothyroidotomy and tracheostomy. Point of care ultrasound of the upper airway can be used in airway assessment to identify distorted airway anatomy, pathological lesions and guide treatment decisions.