Which characteristic of APRV allows patients to breathe freely at different pressure levels?

• A. Time cycling
• B. Volume targeting
• C. Two levels of CPAP
• D. Pressure limiting

Answer: (C)

The characteristic of Airway Pressure Release Ventilation (APRV) that facilitates patients in breathing freely at different pressure levels is the presence of two levels of Continuous Positive Airway Pressure (CPAP). This mode allows the ventilator to maintain two distinct pressure settings: a higher pressure (Phigh) and a lower pressure (Plow).

During the Phigh phase, oxygenation is optimized as the airways remain open, increasing functional residual capacity (FRC) and allowing for improved alveolar recruitment. Patients can initiate breaths spontaneously, and during this period, they experience a more physiological breathing pattern. When the pressure drops to Plow, there’s an opportunity for expiration and the unobstructed flow of air, which encourages spontaneous ventilation. This dual CPAP strategy enables patients to benefit from increased lung volumes while still being able to take breaths at their own pace and pressure, thus promoting patient comfort and effective ventilation.

The other options involve aspects of ventilation modes that do not specifically facilitate this type of unrestricted breathing in the same manner that two levels of CPAP do. For instance, time cycling refers to how breaths are delivered based on time rather than patient effort, while volume targeting and pressure limiting pertain more to specific mechanical control of breaths rather than