Ultrasound Versus Conventional Methods (Mallampati Score and Thyromental Distance) for Prediction of Difficult Airway in Adult Patient without Anticipated Difficult Airway

Background: Unpredictable difficult intubation continues to be a primary reason for morbidity and mortality, and it is regarded as the greatest obstacle to standard care. Therefore, any tool can enhance airway assessment should be considered complementary to the conventional clinical assessment.
Aim of the study: Was to determine if the distance from the skin to the epiglottis, estimated by Ultrasound (US), is useful for predicting laryngoscopy difficulty.
Patients and Methods: This was a prospective, randomized, single-blind clinical study involving sixty patients undergoing elective surgery while under general anesthesia. Three parameters were utilized to assess the airway prior to the operation: the thyrohyoid membrane-level ultrasound-measured distance from skin to epiglottis (DSE), the thyromental distance, and the Mallampati score. The Cormack-Lehane grading system was also used.
Results: Of the 60 included patients, 13 were considered to have difficult laryngoscopy because they showed an increased thickness in the US-measured distance from the skin to the epiglottis. We established that skin to epiglottis distance ≤ 2.15±0.489 cm could predict a difficult laryngoscopy with sensitivity of 80.85%, specificity of 69.23% and area under the receiver operating characteristic curve was 0.764. Slight correlation was found between difficult laryngoscopy and Mallampati score and among thyromental distance and easy laryngoscopy. Mallampati score and thyromental distance had poor area under the curve = (0.728 and 0.530 respectively).
Conclusion: Our research found a strong link among the skin-to-epiglottis distance and the Cormack-Lehane grade in the Egyptian population, suggesting that airway US might be utilized to predict laryngoscopy difficulties.