Which of the following are true about absorption atelectasis?
1) It can occur only when breathing supplemental O₂.
2) Its risk is increased in patients breathing at low tidal volumes (V_T values) .
3) Its risk is decreased through the natural "sigh" mechanism.
4) It results in an increase in the physiologic shunt fraction.

Question

Quizplus · Accepted Answer

1) It can occur only when breathing supplemental oxygen - This statement is false. Absorption atelectasis can occur with any type of breathing, not just supplemental oxygen.
2) Its risk is increased in patients breathing at low tidal volumes - This statement is true. Low tidal volumes lead to decreased recruitment of alveoli and increased risk of collapse.
3) Its risk is decreased through the natural "sigh" mechanism - This statement is true. The "sigh" mechanism, or periodic deep breaths, help recruit collapsed alveoli and decrease the risk of absorption atelectasis.
4) It results in an increase in the physiologic shunt fraction - This statement is false. Absorption atelectasis results in decreased ventilation to affected alveoli, but does not necessarily increase the shunt fraction.

Which of the Following Are True About Absorption Atelectasis