A: Machine-triggered intermittent mandatory ventilation (IMV) with inadequate patient triggering of mandatory breaths. A: Machine-triggered intermittent mandatory ventilation (IMV) with inadequate patient triggering of mandatory breaths. The patient is receiving pressure-controlled, time-cycled, continuous-flow IMV. Points A-C are unassisted spontaneous breaths. At point D the patient begins to exhale, but before exhalation begins, a positive pressure breath is delivered, resulting in breath-stacking and patient-ventilator asynchrony. B: Synchronized intermittent mandatory ventilation. All of the mandatory breaths are patient-triggered and delivered appropriately by the ventilator. (Adapted from Reference 6, with permission.) Melissa K Brown, and Robert M DiBlasi Respir Care 2011;56:1298-1313 (c) 2012 by Daedalus Enterprises, Inc.