Correlation between Airway POCUS Pre Epiglottic Tissue Thickness/Epiglottis to Vocal Cord Distance Ratio and Cormack-Lehane Grading: A Prospective Study in 100 Patients

Background: Predicting difficult laryngoscopy is critical for patient safety in anaesthesia and emergency medicine. Traditional clinical predictors are limited by subjectivity and variability. Point-of-care ultrasonography (POCUS) offers objective, non-invasive airway assessment. The ratio of skin to epiglottis distance (Pre-E) to epiglottis to vocal cord distance (E-VC) may serve as a novel predictor of difficult laryngoscopy. Objectives: To evaluate the correlation between the Pre-E/E-V C ratio measured by airway POCUS and the Cormack-Lehane (CL) grading during direct laryngoscopy, and to assess the predictive value of this ratio for difficult laryngoscopy. Methods: A prospective, observational study was conducted in 100 adult patients (18–70 years) scheduled for elective surgery requiring general anaesthesia and intubation. Preoperative airway assessment included standard clinical predictors and ultrasonographic measurement of Pre-E and E-VC. The Pre-E/E-VC ratio was calculated for each patient. Direct laryngoscopy was performed after induction, and CL grade was recorded. Spearman’s correlation and ROC curve analysis were used to assess the relationship and predictive value of the Pre-E/E-VC ratio. Results: The mean Pre-E was 2.1 ± 0.4 cm, mean E-VC was 1.4 ± 0.2 cm, and mean Pre-E/E-VC ratio was 1.5 ± 0.3. Difficult laryngoscopy (CL Grade III/IV) occurred in 19% of patients. The Pre-E/E-VC ratio showed a moderate positive correlation with CL grade (ρ = 0.52, p < 0.001). A Pre-E/E-VC ratio threshold of 1.7 predicted difficult laryngoscopy with 85% sensitivity and 76% specificity (AUC = 0.87). The Pre-E/E-VC ratio outperformed traditional predictors in sensitivity and specificity. Conclusions: The Pre-E/E-VC ratio measured by airway POCUS is a significant, non-invasive predictor of difficult laryngoscopy, correlating with Cormack-Lehane grading. Routine use of this ultrasonographic parameter, alone or combined with clinical predictors, may improve preoperative airway assessment and patient safety. Keywords: Airway Assessment; Cormack-Lehane Grading; Difficult Laryngoscopy; POCUS.