The Diagnostic Value of Sub-mental Fat Measurement for Prediction of Difficult Laryngoscopy and Intubation: A Randomized Prospective Study

Abstract

Background: Difficult airway management poses a high-risk procedure, potentially leading to patient mortality. Despite significant advancements in modern anesthesia over the years, there remains a lack of a single reliable tool for predicting difficult airways. Objectives: This study aims to examine neck fat diameter as a potential predictor of airway difficulty. Methods: Two hundred fifty patients participated in the study. Airway parameters, including Mallampati score, mandibular protrusion, upper lip bite test, thyromental distance, neck movements, and neck fat diameter, were documented. Results: Among our study population, 48 patients experienced difficult intubation. The Mann-Whitney test revealed that submental fat was significantly greater in the difficult intubation group (P-value < 0.001). Based on the best subset variable selection, submental fat, thyromental distance (model 1), and age (model 2) were selected to participate in the multivariate regression model. Each one mm increase in neck fat was associated with a 30% increase in the odds of difficult intubation (P-value < 0.001) in the univariate logistic model. After adjusting for thyromental distance, age, and gender, the odds of difficult intubation were approximately 2 times higher in patients with 1 mm more neck fat (P-value 0.007). The area under the curve of the Receiver Operating Characteristics curve and McFadden's pseudo-R squared of the multivariate model were 0.998 and 0.91, respectively. Conclusions: Neck fat diameter serves as a reliable and straightforward predictor of airway difficulty and can be used alone or in conjunction with other predictors for the prediction of difficult airway management.