Protocol and statistical analysis plan for the PREOXI trial of preoxygenation with noninvasive ventilation vs oxygen mask.

• Hypoxemia is common during emergency tracheal intubation• Supplemental oxygen prior to intubation (preoxygenation) reduces risk of hypoxemia• The PREOXI trial compares noninvasive ventilation vs oxygen mask preoxygenation• This protocol describes the design, methods, and planned analyses• PREOXI is the largest trial of preoxygenation for emergency intubation to date.