In the event of a hypoxia during ascent, what is the recommended action?

• A. Increase cabin altitude
• B. Rely on altitude decompressors
• C. Administer oxygen and descend if needed
• D. Notify medical support after landing

Answer: (C)

Hypoxia during ascent happens because thinner air provides less oxygen per breath, so tissues can become starved of oxygen. The quickest and most effective response is to administer supplemental oxygen immediately to raise the amount of oxygen reaching the blood, and to descend to a lower altitude if symptoms persist or do not improve with oxygen. Giving oxygen helps restore arterial oxygen levels, supporting brain and body function right away, while descending increases ambient pressure and the partial pressure of oxygen, speeding recovery. Increasing cabin altitude would make the problem worse, not better. Relying on the aircraft’s pressurization or “decompressor” systems is not a reliable fix for an active hypoxia event. Waiting to contact medical support until after landing can delay treatment and worsen outcomes, so treat now and descend as needed.