Which statement describes a phenomenon that leads to intermittent hypoxia in OSA?

Which statement describes a phenomenon that leads to intermittent hypoxia in OSA?

• A. Oxygen sat remains stable during sleep
• B. Recurrent pharyngeal airway collapse during sleep causing intermittent hypoxia and arousals.
• C. Nasal congestion worsens at night but no obstruction
• D. Airway obstruction only during wakefulness

Answer: (B)

Intermittent hypoxia in obstructive sleep apnea happens when the pharyngeal airway repeatedly collapses during sleep, causing cycles of reduced or paused airflow. Each collapse leads to a drop in blood oxygen (desaturation), and the resulting brain arousal briefly restores muscle tone to reopen the airway. This pattern of repeated airway obstruction during sleep directly produces the alternating periods of hypoxia and arousals that define OSA. If oxygen saturation stayed stable during sleep, there wouldn’t be intermittent hypoxia. Nasal congestion that doesn’t cause true obstruction won’t produce the repetitive airway collapse seen in OSA. And airway obstruction that occurs only when awake wouldn’t explain the nocturnal hypoxic episodes characteristic of sleep apnea.

Intermittent hypoxia in obstructive sleep apnea happens when the pharyngeal airway repeatedly collapses during sleep, causing cycles of reduced or paused airflow. Each collapse leads to a drop in blood oxygen (desaturation), and the resulting brain arousal briefly restores muscle tone to reopen the airway. This pattern of repeated airway obstruction during sleep directly produces the alternating periods of hypoxia and arousals that define OSA.

If oxygen saturation stayed stable during sleep, there wouldn’t be intermittent hypoxia. Nasal congestion that doesn’t cause true obstruction won’t produce the repetitive airway collapse seen in OSA. And airway obstruction that occurs only when awake wouldn’t explain the nocturnal hypoxic episodes characteristic of sleep apnea.