Assessment of Epiglottic Depth at Three Different Points with Ultrasound in Predicting Difficult Laryngoscopy: A Prospective Clinical Study.

Introduction: Difficult intubation/laryngoscopy is a challenge both in the operating room and intensive care. The aim of our study was to evaluate whether airway ultrasonography can predict difficult laryngoscopy in adults. Therefore, we have evaluated clinical and ultrasonographic tests to predict difficult laryngoscopy and sought the most sentisitive ultrasonography measurements. Materials and Methods: Following ethical committee approval, airway assessment of 150 ASA 1-3 adults was performed using clinical examination and ultrasonography. Demographic data, body mass index, clinical airway assessment methods, Cormack-Lehane classification were recorded. The depth of epiglottis from the skin at three points in the parasagittal plane were measured with ultrasonography. Ultrasonography data and clinical airway tests were compared among the difficult (D) and easy laryngoscopy groups (E). Mann-Whitney U, chi-square, Fisher’s Exact tests were used for comparisons between groups. Cut-off values were calculated by ROC analysis, p<0.05 was considered statistically significant. Results: Patients in group D were older and their BMI was higher compared to group E. The most predictive ultrasonography measurement was epiglottis depth measured at the upper hyoid border (AUC 0.86, cutoff >24 mm), ratio of epiglottis depth at upper hyoid border/thyrohyoid membrane level (AUC 0.86, cut-off >1.32 mm) (Figures 1 and 2). Four independent clinical and ultrasonograpy variables were found to be correlated with difficult laryngoscopy. Regression analysis revelaed that our model was reliable. Conclusion: Airway assessment with ultrasound doesn’t require patient cooperation. Epiglottis depth from the skin evaluated at 3 levels is a valid criterion in predicting difficult laryngoscopy. Epiglottis depth measured at the level of upper hyoid border was found to be the most sensitive ultrasonography method. Our airway evaluation model revealed that older age, risk of OSAS, epiglottis depth measured at the upper hyoid border, ratio of epiglottis depth at upper hyoid border/thyrohyoid membrane level were the most predictive parameters to predict difficult laryngoscopy. [ABSTRACT FROM AUTHOR]