Transient oxygen desaturation during emergency department intubation is an event with potentially devastating consequences. Pre-oxygenation is an important means of increasing a patient's oxygen reserve and duration of safe apnea prior to intubation. In the emergent setting, important modifications to pre-oxygenation techniques need to be considered to best manage critically ill patients. In this review, we discuss recent updates in pre-oxygenation techniques and evaluate the evidence supporting both commonly used and newly emerging techniques for pre-oxygenation, assessing nature and level of illness, the best delivery method of oxygen, using delayed sequence intubation in patients who cannot tolerate non-invasive pre-oxygenation and using apneic oxygenation via nasal cannula and non-rebreather mask during intubation.