Ultrasonographic Evaluation of Difficult Airway in Obese Patients: A Prospective Study

The management of the airway is difficult in obese patients owing to their anatomical and physiological attributes. This study aims to assess the ultrasonographic measurements of anterior neck soft tissue thickness in diagnosing difficult mask ventilation (DMV) and difficult laryngoscopy (DL) among obese patients.

Patients of age 18-65 years and body-mass index (BMI) >30 scheduled to undergo general anesthesia for elective surgery were included in the study. Ultrasonography-guided measurements of soft tissue distances were performed in the preoperative evaluation room. The distance between the hyoid bone and skin, distance between vocal chord anterior commissure and skin, distance between the trachea and the skin at the level of the suprasternal notch, distance between the thyroid isthmus and skin, and distance between epiglottis and skin were measured. The degree of DMV and DL was quantified.

A total of 128 patients (30 men and 98 women) were enrolled. The average patient age, BMI, and neck circumference were recorded as 50.4 ± 12.2 years, 38.0 ± 5.19 kg/m², and 41.3 ± 4.05 cm, respectively. The incidence of DMV and DL was 11.7% and 10.9%, respectively. DMV exhibited a significant correlation with neck circumference (p = 0.02), whereas difficult airways did not demonstrate any association with anterior neck soft tissue ultrasonography measurements.

Anterior neck soft tissue measurements may not be predictive of DL and DMV in obese patients. Further studies might be helpful in developing new predictors for difficult airway in obese patients.