In pressure-cycled ventilators, what ends the inspiratory phase?

In pressure-cycled ventilators, what ends the inspiratory phase?

• A. Reaching the set inspiratory pressure.
• B. Reaching a predetermined tidal volume
• C. Time-based termination
• D. Expiration triggers

Answer: (A)

In pressure-cycled ventilation, the breath ends when the airway pressure reaches the preset inspiratory pressure. The ventilator continues delivering flow to raise pressure to that limit, then stops inflating and allows expiration to begin. Because the breath is governed by reaching a pressure target rather than delivering a fixed volume, the actual tidal volume can vary with lung compliance and airway resistance. This differs from a volume-cycled approach, where the breath ends after a set tidal volume is delivered, and from time-based termination, where the inspiratory phase ends after a fixed duration. Expiration triggers relate to starting the next breath rather than ending the current inspiratory phase in this context.

In pressure-cycled ventilation, the breath ends when the airway pressure reaches the preset inspiratory pressure. The ventilator continues delivering flow to raise pressure to that limit, then stops inflating and allows expiration to begin. Because the breath is governed by reaching a pressure target rather than delivering a fixed volume, the actual tidal volume can vary with lung compliance and airway resistance.

This differs from a volume-cycled approach, where the breath ends after a set tidal volume is delivered, and from time-based termination, where the inspiratory phase ends after a fixed duration. Expiration triggers relate to starting the next breath rather than ending the current inspiratory phase in this context.