Airway Ultrasound Versus Mallampati Score as a Predictor of Difficult Direct Laryngoscopy in Obese Patients an Observational Study

Abstract

Background: The accuracy of tests has been documented and demonstrated in daily practice; however, a few patients classified as having an easy airway may still present with unexpectedly difficult intubation. Objectives: This study aims to compare the Mallampati score with various airway ultrasound measurements and assess the sensitivity and specificity of different airway ultrasound measurements. The primary outcome is to identify a rapid, non-invasive, and user-friendly tool for predicting difficult laryngoscopy using a readily available device in operating rooms (ultrasound). Methods: This study was an observational, single-blinded, prospective study involving 63 patients. The enrolled participants, aged 18 to 60 years of both sexes, had an American Society of Anesthesiologists (ASA) score of I to III. They were scheduled for an elective surgical procedure that necessitated the insertion of an endotracheal tube, with a Body Mass Index (BMI) higher than 30 kg/m2. Results: The analysis revealed that the distance from the skin to the trachea at the level of the suprasternal notch demonstrated the highest area under the curve (AUC). This was followed by the distance from the skin to the hyoid bone, then the Mallampati test. The least predictive was the distance from the skin to the thyroid cartilage. The Mallampati score had a sensitivity of 41.2% and a specificity of 73.9%. The distance from the skin to the hyoid bone had a sensitivity of 58.8% and a specificity of 80.4%. The distance from the skin to the thyroid cartilage had a sensitivity of 82.4% and a specificity of 37%. Lastly, the distance from the skin to the trachea at the level of the suprasternal notch had a sensitivity of 64.7% and a specificity of 87%. Conclusions: The combination of BMI and Mallampati score with the distance from the skin to the trachea and the distance from the skin to the hyoid bone is thought to show a higher predictive value than the combination with other predictors. However, further investigations need to be conducted with a larger sample size.