Two Neck Ultrasound Measurements as Predictors of Difficult Laryngoscopy

Background: Unpredictable laryngoscopic difficulty remains a dramatic challenge for anaesthesiologists. Ultrasound (US) based airway assessment has been recently proposed as a useful tool in adjunct to clinical methods, but to date few studies are available about the potential role of ultrasound in difficult airway evaluation. The aim of this study is to determine the correlation between the sonographic measurements of anterior cervical soft tissues\'s thickness and Cormack-Lehane grade view at direct laryngoscopy in patients with normal clinical screening tests. Design: Prospective, single blinded, observational study. Number of patients: 300 adult patients Methods: All patients are assessed before surgery to evaluate clinical evidence of difficult airways. Simultaneous ultrasound measures of the anterior cervical soft tissues are performed. At induction of anaesthesia the laryngoscopic view is graded by a different anaesthetist, blinded to the ultrasound assessments. Statistical analysis: Receiver operating characteristic curves (ROC) are used to determine the \"difficulty prediction capability\" of each sonographic measurement and to assess the optimal cut-off scores To allow for comparisons between \"restricted-difficult\" airway and \"easy\" airway groups, a two-sided Student\'s t-test and Fisher\'s exact test is employed as appropriate. The results will be averaged (mean ± standard deviation SD) for each parameter for continuous data. Values of p \< 0.05 are considered as statistically significant.