Look-Alikes: Failed Trigger vs Early Cycling

These breaths are patient-triggered mandatory breaths. The deformation observed in the plateau phase and the expiratory flow-time scalar is caused by the patient’s inspiratory effort. This raises an important question: is the deformation due to the same inspiratory effort that initially triggered the breath and continues into the expiratory phase, or is it a subsequent inspiratory effort that begins during the plateau phase and extends into expiration?

If it is the same effort that triggered the breath and persists into expiration, this represents early cycling dyssynchrony. However, if a new inspiratory effort starts during the plateau phase and continues into expiration, it may indicate an ineffective effort or failed trigger. This typically occurs when there is a significant delay in cycling, causing the patient to complete one neural breath and begin another within the duration of a single mandatory breath.

In this case, the deformation of the plateau and expiratory phases was due to another inspiratory effort, confirmed by physical examination of the patient. This occurred because of a significant delay in ventilator cycling, during which the patient completed one neural breath and initiated another within the same mechanical inspiratory phase—a phenomenon known as late cycling. Since the second inspiratory effort occurred during the ongoing inspiratory phase and failed to trigger a new breath, it can be labeled as an ineffective effort or failed trigger.