Utility of ultrasound assessment for predicting difficult intubation in adult surgical patients.

Difficult or failed intubation is a major and life threatening complication that may occur during induction of general anaesthesia. Thorough preoperative airway assessment is an important component of establishing a safe plan to secure patients’ airways perioperatively. Ultrasound technology is rapidly evolving and becoming more accessible as costs decrease and devices become both more portable and user-friendlier. The use of the ultrasound in airway assessment has been described as early as the 1980s, and recently there has been increasing interest in the use of this technology among anaesthetists worldwide. Ultrasound used in conjunction with clinical airway assessment has multiple advantages and there is a rapidly growing body of evidence supporting its use. Ultrasound can be used to view the majority of the upper airway structures, including the mouth, tongue, oropharynx, hypopharynx, hyoid bone, larynx, vocal cords, cartilages, trachea and oesophagus. In this prospective observational study we will assess the upper airway of patients presenting for surgery requiring endotracheal intubation in a tertiary hospital for potential difficult airway. This will be done both clinically and using an M- Turbo SonoSite ultrasound machine. We will measure the hyomental distance in neutral and the hyperextended position and will assess the anterior neck thickness at the level of the hyoid and thyrohoid membrane. Pre operative results and perioperative airway management including any difficulties with intubation will be documented and compared accordingly. The objectives of this study are to determine the utility of the use of the ultrasound to predict a difficult intubation, and examine the association, if any, between ultrasound measurements and difficult airway clinical screening tests.