**5. Reoxygenation**

When airway obstruction is relieved during apnea, there is a flow of gas through the pressureless thorax. Securing a high FiO<sup>2</sup> during this one passive inhalation saves time to save the airway. Securing a high FiO<sup>2</sup> during this one-time passive inhalation may lead to a significant prolongation of the duration of the apnea. If airway obstruction is relieved with 100% oxygen, the patient is likely to have a temporary improvement in hemoglobin oxygen desaturation, even though the tidal volume is not maintained and inspired oxygen volume is small.
