Hypoxemia is a life threatening complication during emergency airway management. Despite advances in technology and training, hypoxemia still occurs in up to a quarter of all intubations placing patients at high risk for damage to vital organs and death. A key method in the prevention of hypoxemia is known as preoxygenation which has been shown to decrease the incidence of hypoxemia. Currently there are two conventional methods for preoxygenation in the literature, however recently a new method has been described as a possible alternative method. What is unclear in the literature is if one modality is superior than the other for preoxygenation. The goal of this interventional study is to determine if one method of preoxygenation is superior to the other. This is a 3 arm interventional cross over designed study comparing three interventional methods for preoxygenation. Non-rebreather mask, bag-valve mask and high flow nasal cannulae.