Preoxygenation with a bag-valve-mask device did not reduce the risk for hypoxemia compared with preoxygenation with a facemask during emergency tracheal intubation in the emergency department (ED) or ICU setting.

"Preoxygenation with a bag-valve-mask device did not reduce the risk of hypoxemia compared to preoxygenation with facemask oxygen in critically ill patients undergoing emergency tracheal intubation in the ED or ICU setting," the authors wrote.

The study was led by Christopher D. Chou, MD, Wake Forest School of Medicine, Winston-Salem, North Carolina. It was published online on July 22, 2025, in the Annals of Emergency Medicine.

The lack of randomization may have introduced residual confounding despite propensity adjustment. Key preoxygenation details -- including oxygen mask flow rates, which could have modified the fraction of inspired oxygen, and the use of a positive end-expiratory pressure valve, which could have affected lung oxygen content -- were not recorded. The study was underpowered by the small bag-valve-mask cohort; therefore, modest differences between techniques may have been missed. Additionally, although hypoxemia during tracheal intubation was the primary outcome, it was not patient-centered.

The primary studies from which the data were derived were funded by the Defense Health Agency J9 Restoral program. The authors reported having no conflicts of interest.