An observational study of ultrasound guided airway assessment for predicting difficult laryngoscopy in obese patients

Endotracheal intubation is one among the vital skills for anesthesiologist. Failure or delay to secure the airway can cause life-threatening morbidity and mortality, especially in the obese patients. Therefore, unanticipated difficult intubation remains a primary concern to anesthesiologist. Airway management plays a crucial role in anesthetic practice. Failure of airway management remains primary concern for anesthesiologist. There are various tests available for assessing difficult airway, but they have poor discriminative power when used alone as compared to a combination of tests. Modified Mallampati score, thyromental distance (TMD), sternomental (SM) distance, upper lip bite test  are widely recognized methods for predicting difficult laryngoscopy. In patients with short neck, double chin (which makes neck extension limited), buck tooth difficult intubation is anticipated, also if patient is edentulous mask holding is difficult.

Despite having many tests to assess airway, unanticipated difficult airway still remains a major concern. The unanticipated difficult airway can lead to cannot ventilate and cannot intubate situation.

In such situations a more scientific approach to airway assessment and management becomes necessary. Most cases of unanticipated difficult intubation are managed satisfactorily, but problems with tracheal intubation could cause serious soft tissue damage and are the principal cause of hypoxemic brain damage and anesthetic death. So management of the difficult laryngoscopy and tracheal intubation must be planned well in advance for maintenance of oxygenation and to prevent airway trauma. The problem becomes more pronounced in case of obes patients. So using ultrasonography preoperatively helps assess the airway in obese and predict difficult laryngoscopy. Patients chosen for the study had BMI >25 kg/m². Using ultrasound we measure tongue thickness, skin to epiglottis distance, skin to vocal cords distance.  Also we will time intubation duration and assess if and maneuver was done and any other instruments used.