““Cycle asynchrony is present when the ventilator inspiratory (Ti-vent) and expiratory times are different from that of the patient’s neural inspiratory (Ti-pt) and expiratory times. Double cycling in VCV suggests that the patient is still inspiring when the ventilator is turned off (Ti-pt>Ti-vent). Lengthening inspiratory time by adding an inspiratory pause or reducing flow may help, as might increasing VT. An end-inspiratory spike in the pressure-time waveform suggests that the patient is trying to exhale, while the ventilator is still pushing (Ti-pt < Ti-vent); increasing the set flow or reducing VT might alleviate this. The PCV may be helpful in this situation, but the inspiratory time is still constant and may not be comfortable. A trial of high-level PS might be attempted, although some new ventilators allow PCV to be flow cycled and to function like PS with a backup rate.””
