Which mode actively targets a set tidal volume by adjusting pressure breath by breath?

• A. PRVC/APV-CMV
• B. APRV
• C. SIMV
• D. AC

Answer: (A)

PRVC/APV-CMV delivers a set tidal volume by using a breath-by-breath feedback loop that adjusts inspiratory pressure to hit the target. After each breath, the ventilator assesses the actual tidal volume and, if it’s below the goal, raises the inspiratory pressure slightly for the next breath; if it’s above the goal, it lowers the pressure. This keeps the delivered volume consistent while keeping pressures within safe limits. This dynamic pressure adjustment distinguishes it from other modes: APRV holds high continuous pressures with breaths released periodically and doesn’t continuously target a specific VT; SIMV and AC provide breaths at fixed pressures or volumes without this automatic, on-the-fly pressure tuning to reach a precise tidal volume. So the mode that matches the description is the one that uses pressure adjustments to achieve the set tidal volume on each breath.