Point‐of‐care ultrasound of the upper airway in difficult airway management: a systematic review and meta‐analysis*
Vedish Soni, Ameya Pappu, Sahar Zarabi, Carlos Khalil, Kong Eric You-Ten, Naveed Siddiqui, David T. Wong, Vincent Chan, Qixuan Li, Ella Huzsti, Marina Englesakis, Mandeep Singh
Abstract
INTRODUCTION: The utility of bedside screening tests for the prediction of difficult airways is limited. There is growing interest in the role of point-of-care-ultrasound in airway assessment and management. This systematic review and meta-analysis aimed to determine the diagnostic utility and clinical application of various upper airway point-of-care-ultrasound parameters in the prediction of difficult airways. METHODS: We searched databases for randomised controlled trials, observational studies and case series with more than five cases. RESULTS: In total, 60 studies involving 10,580 patients, evaluating 58 parameters were included. For difficult facemask ventilation, a narrative synthesis showed that increased tongue thickness was associated with an increased incidence of a difficult airway. For prediction of difficult laryngoscopy, the sensitivity, specificity and area under the receiver operator characteristic curve (AUROC) for distance from-skin-to-vocal-cords were 0.84 (95%CI 0.74-0.91), 0.81 (95%CI 0.61-0.92) and 0.87 (95%CI 0.78-0.89), respectively (high certainty of evidence). For prediction of difficult tracheal intubation, distance from skin-to-epiglottis had the highest sensitivity (0.80 (95%CI 0.74-0.85)) and specificity (0.86 (95%CI 0.74-0.91)) (high certainty of evidence), while distance from skin-to-hyoid had the highest AUROC of 0.86 (95% CI 0.73-0.92), with a sensitivity and specificity of 0.78 (95%CI 0.60-0.89) and 0.81 (95%CI 0.63-0.91), respectively (moderate certainty of evidence). Ultrasound use was associated with higher first pass success in percutaneous tracheostomy (odds ratio (95%CI) 3.9 (2.1-71), (low-moderate certainty of evidence)) and improved cricothyroid membrane identification compared with palpation (odds ratio (95%CI) 3.61 (2.20-5.92) (moderate-high certainty of evidence)). DISCUSSION: Upper airway point-of-care ultrasound may improve prediction of difficult airways; its use is associated with improved first pass success in percutaneous tracheostomy. Future research should focus on evaluating its use in combination with a focused history and standard bedside examination tests, and in at-risk patient populations.