Ultrasound-measured cutaneous-epiglottic distance for predicting difficult laryngoscopy: an observational study

Area of Science:

• Anesthesiology
• Medical Imaging
• Airway Management

Background:

• Ultrasound (US) enables rapid bedside airway assessment.
• Predicting difficult laryngoscopy is crucial for patient safety.
• Existing methods for airway assessment have limitations.

Purpose of the Study:

• To evaluate the US-measured cutaneous-epiglottic distance (CED) in predicting difficult laryngoscopy (Cormack-Lehane grades 3–4).
• To assess the association between CED, sex, and body mass index (BMI).
• To determine independent associations between CED and increased odds for difficult laryngoscopy.

Main Methods:

• Prospective study of adult patients undergoing elective surgery with general anesthesia.
• Exclusion of patients with BMI > 35 kg/m² or prior difficult intubation history.
• Measurement of CED in anesthetized patients before tracheal intubation.
• Analysis using Receiver Operator Characteristic (ROC) curves and logistic regression.

Main Results:

• ROC curve analysis showed an area under the curve of 0.899, indicating high discriminatory capability.
• A CED cut-off of 25.6 mm was identified as optimal for predicting difficult laryngoscopy.
• Both CED and BMI were independently associated with increased odds for difficult laryngoscopy (OR for CED = 1.81, BMI = 1.30).

Conclusions:

• US-measured CED is a valuable tool for predicting Cormack-Lehane grades during direct laryngoscopy.
• CED demonstrates high discriminatory capability for both lower (1–2) and higher (3–4) grades.
• CED is positively correlated with BMI and independently predicts difficult laryngoscopy.