Which cycling ends a breath when flow drops to a specific percentage of peak flow?

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

Answer: (B)

Flow cycling ends a breath when inspiratory flow falls to a preset percentage of the peak inspiratory flow. This means the ventilator stops inhalation as soon as the patient’s demand wanes, allowing support to taper with the patient’s effort and helping avoid overdistension. Time cycling would cut off the breath after a fixed inhalation time, not in response to how fast air is moving; volume limit ends the breath once a target tidal volume is reached, regardless of flow dynamics; exhalation is simply the phase that follows inhalation, not a trigger to terminate inspiration. The percentage threshold (often a fraction of the peak flow) provides a flexible, patient-responsive end to inspiration.