Abstract No. : ABS1378: Correlation between upper airway ultrasound and Cormack- Lehane grading during laryngoscopy-A prospective study

Abstract

Background & Aims:Difficult and failed tracheal intubation after direct laryngoscopy is a dreaded complication of general anaesthesia. Preoperative prediction of the Cormack-Lehane (CL) grade with ultrasonographic measurements of ANS-Hyoid, ANS-VC, PES&EVL can help in better airway management during general anaesthesia.Methods:We studied 100 patients undergoing elective surgery under general anaesthesia. Study was carried out in two phases. Firstly, during preanaesthetic checkup, Mallam pati grade (MPG), Sternomental distance (SMD), Thyromental distance (TMD) and ultrasound measurements of the anterior neck soft tissue thickness at the level of the hyoid (ANS-Hyoid), at the level of the vocal cords (ANS-VC) and ratio of the depth of the pre-epiglottic space (Pre-E) to the distance from the epiglottis to the mid-point between the vocal cords (E-VC) were obtained, CL grade was noted during laryngoscopy. Chi-square test wasapplied to predict any statistically correlation between measurement of ultrasonographic parameters and CL grade.Results:The incidence of difficult intubation was 15%. An ANS-VC>0.32 had sensitivity of 100% in predicting a CL grade of 3 and4, which was higher than ANS-hyoid, PES/EVL, MPG, SMD, TMD, while specificity and PPV were lower. Conclusion:Ultrasound is a useful test in airway assessment. ANS-VC>0.32 is a potential predictor of difficult intubation. ANS-hyoid, PES/EVL are not indicative of difficult intubation.