Double-triggering

Tracings of airway pressure (Paw), flow, and volume in a sedated patient undergoing assist-control mechanical ventilation, depicting classic and frequent dyssynchrony of double cycling. Despite a set rate of 20/minute, the actual rate is 40/minute. Diaphragmatic electrical activity signal (EaDi), superimposed on the Paw curve, provides the mechanism, called reverse triggering. Diaphragmatic contractions are triggered by the mechanical insufflations on a 1:1 basis and explain the second cycle.