ineffective trigger asynchrony

Ventilator graphics including pressure vs time (top), flow vs time (second from top), volume vs time (next to bottom), and electrical activity of the diaphragm vs time using a NAVA catheter (bottom) that demonstrates multiple episodes of ineffective trigger asynchrony (arrows).

Ineffective trigger occurs when an inspiratory effort does not trigger a ventilator breath.

In Figure 4, there is evidence of diaphragmatic activity via the NAVA catheter (green arrows) that is not followed by delivery of a positive pressure breath. One can detect evidence of ineffective triggering by slight drop in airway pressure (yellow arrows). At the bedside, observing the ventilator graphics for positive pressure breaths while detecting patient inspiratory efforts with your hand on the patient’s chest can confirm the presence and frequency of ineffective respiratory efforts.