Which measurement helps distinguish central from obstructive apnea during sleep study?

Which measurement helps distinguish central from obstructive apnea during sleep study?

• A. Oro-nasal airflow
• B. Chest and abdominal effort
• C. SpO2
• D. EEG

Answer: (B)

The key idea is that identifying the type of apnea relies on whether there is respiratory effort during the pause. Chest and abdominal effort sensors measure the work of breathing, so they reveal if the body is trying to breathe during the event. In a central apnea, there’s little to no respiratory effort during the pause, so the chest and abdomen show minimal movement even though airflow is absent. In an obstructive apnea, the airway collapses and airflow stops, but the respiratory muscles keep trying, so you still see chest and abdominal effort despite little or no airflow. That direct signal of effort is what lets you differentiate between the two. Oro-nasal airflow tells you whether air is moving, but not whether effort is present. SpO2 shows the consequence of the event (desaturation) rather than the mechanism. EEG indicates brain activity and arousal, not the mechanics of breathing.

The key idea is that identifying the type of apnea relies on whether there is respiratory effort during the pause. Chest and abdominal effort sensors measure the work of breathing, so they reveal if the body is trying to breathe during the event.

In a central apnea, there’s little to no respiratory effort during the pause, so the chest and abdomen show minimal movement even though airflow is absent. In an obstructive apnea, the airway collapses and airflow stops, but the respiratory muscles keep trying, so you still see chest and abdominal effort despite little or no airflow. That direct signal of effort is what lets you differentiate between the two.

Oro-nasal airflow tells you whether air is moving, but not whether effort is present. SpO2 shows the consequence of the event (desaturation) rather than the mechanism. EEG indicates brain activity and arousal, not the mechanics of breathing.