Time to oxygenation for cannula- and scalpel-based techniques for emergency front-of-neck access: a wet lab simulation using an ovine model.

Emergency front-of-neck access to achieve a percutaneous airway can be a life-saving intervention, but there is debate about the preferred technique. This prospective, observational study was designed to compare the two most common emergency surgical airway techniques in a wet lab simulation using an ovine model. Forty-three doctors participated. After providing standardised reading, a lecture and dry lab benchtop training, participants progressed to a high-fidelity wet lab simulation. Participants entered an operating theatre where a 'cannot intubate, cannot oxygenate' situation had been declared and were directed to perform emergency front-of-neck access: first with a cannula technique (14-gauge cannula insertion with ventilation using a Rapid-O2® cricothyroidotomy insufflation device); and subsequently, a scalpel-bougie technique (surgical incision, bougie insertion into trachea and then tracheal tube passed over bougie, with ventilation using a self-inflating bag). The primary end-point was time from declaration of 'cannot intubate, cannot oxygenate' to delivery of oxygen via a correctly placed percutaneous device. If a cannula or tracheal tube was not placed within 240 s, the attempt was marked as a failure. There was one failure for the cannula approach and 15 for the scalpel-bougie technique (OR 0.07 (95%CI 0.00-0.43); p <0.001). Median (IQR [range]) time to oxygenation, if successful, was 65 (57-78 [28-160]) s for the cannula approach and 90 (74-115 [40-265]) s for the scalpel-bougie technique (p=0.005). In this ovine model, emergency front-of-neck access using a cannula had a lower chance of failure and (when successful) shorter time to first oxygen delivery compared with a scalpel-bougie technique.