Depth to the airway lumen at the level of the cricothyroid membrane measured by ultrasound.

Background: Knowing the likely depth to the airway before emergency cricothyroidotomy may improve success in cases where it cannot be measured. Our aim was to measure the depth to the airway at the cricothyroid membrane by ultrasound in a large group of adult patients.

Method: Prospective, observational study in two centres, Oxford and Gloucester.