RecruitingDevice studyEnd-Tidal Oxygen for Intubation in the Emergency DepartmentRapid Sequence Intubation (RSI) is a high-risk procedure in the emergency department (ED). Patients are routinely preoxygenated (given supplemental oxygen) prior to RSI to prevent hypoxia during intubation. For many years anaesthetists have used end-tidal oxygen (ETO2) levels to guide the effectiveness of preoxygenation prior to intubation. The ETO2 gives an objective measurement of preoxygenation efficacy. This is currently not available in most EDs. This trial evaluates the use of ETO2 on the rate of hypoxia during intubation for patients in the ED.