Sternomental Displacement and Neck Circumference as Predictors of Difficult Airway in Obese Patients During General Anesthesia: a Prospective Observational Cohort Study

Difficulties airway significantly contribute to the morbidity and mortality associated with anesthesia. Identifying situations and patients at risk for airway management problems is the key to optimal care and has been the focus of numerous publications. Although controversial, Body Mass Index (BMI) is considered as associated with difficult intubation in both and operating theaters. A modified measurement of SMD is obtained with the head in neutral position (SMD neutral), then the difference between SMD extension and SMD neutral was calculated and it was referred to as sternomental displacement (SMDD). SMDD was proved to be a good objective predictor for difficult laryngoscopy in adult patients, and its predictive ability was increased when combined with other tests as neck circumference (NC). To the best of our knowledge, the validity of the SMDD test was not previously assessed in obese patients.