Comparison between clinical and ultrasound guided airway assessment in predicting difficult airway: a prospective, observational study

Abstract

Background: The traditional screening tools used for predicting the difficult airway are not very reliable. Ultrasound has evolved as a probable tool for airway assessment. The aim of this study was to compare the clinical and ultrasound guided airway assessment in predicting difficult airway. Materials and Methods: This prospective, observational study analyzed a sample of 200 patients who were categorized as having easy (grades 1 and 2) or difficult (grades 3 and 4) laryngoscopy based on the laryngoscopic criteria of Cormack-Lehane. The clinical assessment included Mallampati score, thyromental distance, and interincisor gap. Ultrasound parameters included skin-to-vocal cord distance, skin-to-epiglottis distance, hyomental distance, and tongue thickness. Univariate and multivariate regression analysis was used for the statistical analysis. Sensitivity, specificity, and overall accuracy were also identified. Results: Out of 200 patients, 32 (16%) were identified as difficult laryngoscopy, whereas 168 patients (84%) were identified as easy laryngoscopy. All predictors of difficult intubation employed in this study provided accurate predictions (P < 0.05). The accuracy was Mallampati grade (78%), interincisor distance (17%), thyromental distance (80.81%), skin-to-epiglottis distance (89%), skin-to-vocal cords distance (91%), hyomental distance (76%), and tongue width (73%). Conclusion: Both clinical and ultrasound parameters were able to predict difficult intubation, but the sonographic parameter skin-to-vocal cords distance showed the highest accuracy compared to the other parameters. A combined approach can enhance the prediction of a difficult airway.

Keywords

• airway
• difficult intubation
• ultrasound