During preoxygenation for endotracheal intubation, high-flow nasal oxygen used to extend the apneic window is called what?

• A. Denitrogenation.
• B. Apneic oxygenation.
• C. Passive ventilation.
• D. Active ventilation.

Answer: (B)

Apneic oxygenation is the practice of delivering oxygen during a period of apnea to extend the time before desaturation occurs. High-flow nasal oxygen provides a continuous, humidified oxygen stream through the nose, which helps keep oxygen in the airways and alveoli even when you’re not actively ventilating. This creates a reservoir of oxygen and a slight positive pressure that flushes dead space, allowing ongoing diffusion of oxygen into the bloodstream while you perform intubation.

Denitrogenation, by contrast, is the preoxygenation goal of replacing nitrogen with oxygen to maximize the oxygen reservoir in the lungs, but it’s about preparation before apnea, not the ongoing delivery during apnea. Passive ventilation and active ventilation imply some form of airflow or mechanical breaths, which are not describing the oxygen delivery during the apnea period itself.