Preoxygenation: Physiologic Basis, Benefits, and Potential Risks

Usharani Nimmagadda, MD; M. Ramez Salem, MD; George J. Crystal, PhD


Anesth Analg. 2017;124(2):507-517. 

In This Article


The literature provides overwhelming evidence that preoxygenation, whether instituted before induction or to emergence from anesthesia, delays the onset of hypoxemia during apnea. On that basis, preoxygenation should be performed in all patients given general anesthesia. Preoxygenation should also be performed whenever there is an anticipated interruption of O2 delivery, such as during open tracheobronchial suctioning, and before and during awake fiber-optic intubation, especially in high-risk patients, such as the supermorbidly obese. The technique should be performed correctly, with monitoring of EtO2. Because the advantage of preoxygenation may be blunted in high-risk patients, various maneuvers are available to prolong its effectiveness. The clinician should be familiar with these maneuvers. Absorption atelectasis during preoxygenation can be readily minimized, and thus it should not be a deterrent to the routine use of the technique.