Athanassoglou V, et al. - Via a prospective, observational study in two centres, Oxford and Gloucester of 352 patients presenting for a large variety of surgical operations, researchers measured the depth to the airway at the cricothyroid membrane by ultrasound in a large group of adult patients. Depth to the airway lumen was strongly related to weight and to a lesser extent, BMI though, it did not correspond to gender. The statistical analysis produced an equation to prognosticate the upper 95% CI of depth to the airway from the patient's weight and depth to the airway lumen in mm = (0.13 x weight in kg) + 0.86. Thus, if an ultrasound measurement is not possible prior to the emergency cricothyroidotomy, the clinician could use the outcomes to prognosticate the depth to the airway by using the patient's weight. If the upper 95% CI was used as the depth of incision, it would enter the airway in 39 of 40 patients of that weight, with no damage to posterior structures in those with a shallower airway.