Preoxygenation, Reoxygenation, and Delayed Sequence Intubation in the Emergency Department

Scott D. Weingart, MD


J Emerg Med. 2011;40(6):661-7. 

In This Article

Abstract and Introduction


Background: The goal of preoxygenation is to provide us with a safe buffer of time before desaturation during Emergency Department intubation. For many intubations, the application of an oxygen mask is sufficient to provide us with ample time to safely intubate our patients. However, some patients are unable to achieve adequate saturations by conventional means and are at high risk for immediate desaturation during apnea and laryngoscopy. For these patients, more advanced methods to achieve preoxygenation and prevent desaturation are vital.
Discussion: We will review the physiology of hypoxemia and the means to correct it before intubation. Next, we will discuss apneic oxygenation as a means to blunt desaturation and the optimal way to reoxygenate a patient if desaturation does occur. Last, we will discuss the new concept of delayed sequence intubation, a technique to be used when the discomfort and delirium of hypoxia and hypercapnia prevents patient tolerance of conventional preoxygenation.
Conclusions: These new concepts in preoxygenation and reoxygenation may allow safer airway management of the high-risk patient.


Conventional preoxygenation techniques provide safe intubation conditions for a majority of emergency airways. However, in a subset of patients, these techniques will lead to inadequate preoxygenation and fail to prevent desaturation. To safely intubate this group, an understanding of the physiology of oxygenation is essential to allow for optimal intubating conditions. This knowledge can then be applied at the bedside in the care of high-risk patients. The goal of this work is to translate the tenets of physiology and the most recent literature to allow the safest possible intubation of critically ill patients.