Which cycling mode terminates breath when the target tidal volume is reached?

• A. Flow Cycling
• B. Volume Cycling
• C. Exhalation
• D. Time Cycling

Answer: (B)

Volume cycling ends the inspiratory phase once the delivered tidal volume reaches the preset target. The ventilator continuously measures the volume of air the patient receives; when that accumulated volume hits the set goal, inspiration stops and expiration begins. This guarantees a consistent tidal volume per breath, even if patient effort or airway resistance changes. By contrast, flow cycling ends when inspiratory flow drops to a predefined threshold, which can occur at different volumes depending on lung mechanics. Time cycling ends after a fixed inspiratory time, so the resulting volume can vary with compliance and resistance. Exhalation is simply the expiratory phase that follows inspiration, not a cycling trigger.