In ARDS Crs typically falls to what range?

In ARDS Crs typically falls to what range?

• A. 10-20
• B. 25-35
• C. 35-45
• D. 60-70

Answer: (C)

In ARDS the lungs become stiff because of diffuse alveolar damage, edema, and atelectasis, so the respiratory system loses its ease of expansion. This lowers respiratory system compliance (Crs), which is the amount of volume gained per unit of pressure change. Normal Crs is higher, but in ARDS the value typically sits in the mid-30s to mid-40s mL per cmH2O. That means you get less volume for each centimeter of airway pressure, which is why ventilator settings aim to use lower tidal volumes and appropriate positive end-expiratory pressure to recruit open airways without causing injury. Values that are much lower (like 10–20) would indicate extreme stiffness or additional problems beyond typical ARDS, while much higher values (60–70) would be closer to normal lung compliance.

In ARDS the lungs become stiff because of diffuse alveolar damage, edema, and atelectasis, so the respiratory system loses its ease of expansion. This lowers respiratory system compliance (Crs), which is the amount of volume gained per unit of pressure change. Normal Crs is higher, but in ARDS the value typically sits in the mid-30s to mid-40s mL per cmH2O. That means you get less volume for each centimeter of airway pressure, which is why ventilator settings aim to use lower tidal volumes and appropriate positive end-expiratory pressure to recruit open airways without causing injury. Values that are much lower (like 10–20) would indicate extreme stiffness or additional problems beyond typical ARDS, while much higher values (60–70) would be closer to normal lung compliance.