Abstract

Background: Prediction of difficult airway is a challenging task. Commonly used airway assessment screening tests has high interobserver variability and low predictability in detecting difficult airway. Ultrasound could be a helpful tool in the prediction of these difficulties. Objectives: The purpose of this study was to evaluate the ability of preoperative ultrasound assessment of anterior neck soft tissue thickness in predicting difficult laryngoscopy in patients undergoing during elective surgery requiring tracheal intubation. Design: Prospective; Double blind; Observational study. Patients: A total of 100 patients aged more than 18 years, without neck pathologies undergoing general anesthesia and tracheal intubation were included in the study. Outcome Measures: Ultrasound distance from skin surface to anterior commissure of vocal cord (DSVC) was recorded with a linear 6 to 13 MHz ultrasound transducer preoperatively. Postoperative anesthesia record was analyzed for Cormac Lehane grades during laryngoscopy. Results: The DSVC cutoff value of 0.51 cm was the best predictor of Cormack Lehane grade more than 2 at direct laryngoscopy and of difficult intubation, (sensitivity 78.3%, specificity 74%). The mean (SD) of DSVC was 0.53 (0.12) cm in the difficult laryngoscopy group and 0.40 (0.14) cm in the easy laryngoscopy group, (p < 0.001). Conclusion: The noninvasive prediction of difficult laryngoscopy can be done by airway ultrasound. The distance of 0.51 cm or more at the level of vocal cord can predict potential difficult laryngoscopy in patients undergoing anesthesia with endotracheal intubation.

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