Correlation between preoperative ultrasonographic airway assessment and laryngoscopic view in adult elective surgical patients: A prospective observational study
Himadarshini L, Ganapathi P, Dr. Anish Sharma NG
Background: Difficult intubation is associated with serious morbidity and mortality and cannot be always predicted by conventional clinical predictors. Ultrasonographic airway assessment could be a useful predictor of difficult airway and it thus correlates with various clinical and laryngoscopic view of airway which is the Cormack- Lehane grading.Aims and Objectives: To find out the correlation between ultrasonographic airway assessment and clinical airway assessment for difficult airway prediction and to compare the results with Cormack-Lehane grading during intubation.Materials and Methods: The study population includes 155 adult patients undergoing elective surgery under general anaesthesia. This is a prospective observational study where both the clinical airway assessment parameters and ultrasonographic parameters are noted and correlated. In clinical assessment- Modified Mallampati class, Mouth Opening, Thyromental Distance in flexion, Thyromental Distance in full extension, Neck Circumference, Neck Extension angle were assessed. In ultrasonographic parameters- Skin to hyoid distance, Skin to epiglottis distance, Anteroposterior thickness of the geniohyoid muscle. The anterior neck soft tissue thickness at the level of hyoid and vocal cord were assessed. All these parameters were compared with Cormack- Lehane grading.Results: Among the clinical parameters, Mallampati classification has maximum sensitivity and specificity. And among the ultrasonographic parametersANS-VC has maximum sensitivity of 95.1% and sensitivity of 85.7% and is significant. PRE-E, E-VC, PRE-E/E-VC is also significant with p value of <0.001. Hence, it correlates with CL grade. ANS-hyoid is not statistically significant. Conclusion: Ultrasonographic measurement of anterior neck soft tissue- Vocal cord is an excellent predictor of difficult intubation. The most sensitive parameter compared to other clinical parameters. Measurement of Anterior neck soft tissue-Hyoid is not a useful indicator in predicting difficult intubation.