What ventilator mode delivers breaths that are pressure-controlled but targeted to achieve a specific tidal volume by adjusting pressure?

• A. Assist-Control
• B. SIMV
• C. PRVC
• D. CPAP

Answer: (C)

PRVC (Pressure Regulated Volume Control) uses breaths that are pressure-limited but automatically adjusts the inspiratory pressure to hit a target tidal volume. If the delivered volume is too low because of changing lung compliance or resistance, the machine increases the inspiratory pressure on subsequent breaths. If the volume is too high, it lowers the pressure. This closed-loop adjustment keeps the tidal volume consistent while avoiding unnecessarily high pressures, blending protection with guaranteed ventilation.

This differs from other modes: Assist-Control delivers a set tidal volume or pressure without automatic pressure adjustments to reach a target; SIMV provides a set number of breaths with fixed volumes and allows patient-triggered breaths between them; CPAP maintains continuous airway pressure with spontaneous breaths and does not target a specific tidal volume.