Which hemodynamic effect is commonly associated with APRV?

• A. Increased venous return
• B. Decreased venous return due to elevated intrathoracic pressures
• C. No effect on hemodynamics
• D. Improved cardiac output due to constant PEEP

Answer: (B)

APRV raises mean airway pressure by holding a high airway pressure for extended periods with brief releases to allow ventilation. That higher intrathoracic pressure diminishes the pressure gradient driving blood back to the heart, so venous return (preload) is reduced. With less blood filling the heart, cardiac output can fall, especially in patients with limited cardiac reserve. So the commonly observed hemodynamic effect is decreased venous return due to elevated intrathoracic pressures. The other options don’t fit: increasing venous return would require lower intrathoracic pressures; APRV typically increases them. There is usually some hemodynamic effect, not no effect, and APRV’s impact on CO is more about reduced preload from higher intrathoracic pressure rather than an improvement from a constant PEEP.