Ultrasound-Measured Skin-to-Epiglottis Distance as a Predictor of Difficult Intubation in Obese Patients: A Prospective Observational Study.

Abstract

Background/Objectives: Difficult intubation is a significant clinical issue in emergency medicine as well as anesthesia practice, occurring more frequently in obese patients. Traditional assessment methods may not be sufficient to predict difficult intubation. This study aims to evaluate the ability of ultrasound-measured skin-to-epiglottis distance (SED) to predict difficult laryngoscopy in obese patients and investigate its applicability in clinical practice. Methods: This prospective observational study was conducted between February 2024 and January 2025 at Gaziantep City Hospital on obese patients undergoing bariatric surgery. Patients aged 18 years and older with an American Society of Anesthesiologists (ASA) classification of I-II-III were included in the study. Demographic data, standard airway assessment parameters (neck circumference, thyromental distance, sternomental distance, etc.), and ultrasound-measured skin-to-epiglottis distance were recorded. All intubation procedures were performed by a single experienced anesthesiologist following standard protocols, and laryngoscope view was assessed according to the Cormack-Lehane classification. Results: Among the 61 patients included in the study, 16.4% were classified as having a difficult airway, and 13.1% experienced difficult intubation. No significant correlation was found between standard airway assessment parameters and difficult intubation. However, ultrasound-measured skin-to-epiglottis distance (SED) was significantly higher in patients with difficult intubation (p = 0.004), making it a strong predictor. Additionally, modified Mallampati (p < 0.001), modified Cormack-Lehane (p = 0.003), and Wilson scores (p = 0.001) were significant in predicting difficult airway, although Wilson score was not significant for difficult intubation (p = 0.099). Conclusions: Our study suggests that ultrasound-measured skin-to-epiglottis distance may be a valuable predictor of difficult intubation in obese patients. Given the limitations of preoperative assessment methods, incorporating ultrasound into airway evaluation as a complementary tool provides significant benefits. Larger-scale studies in the future are necessary to further assess the clinical efficacy of this method.