[Intermittent mandatory ventilation]

Intermittent mandatory ventilation (IMV) is a mode of ventilation that allows the patient to make spontaneous breaths during the expiratory phase of mandatory ventilator breaths. There are two types of IMV according to whether respirator breaths are synchronized with the patient's respiratory efforts: Non-synchronized IMV and synchronized IMV (SIMV), and according to whether SIMV is volume- or pressure programmed. The main advantage of SIMV is that the respirator delivers the preset ventilator pressure and rate while allowing the patient to breath spontaneously, thus facilitating progressive weaning from mechanical ventilation. It diminishes the risk of barotrauma, produces less hemodynamic com-promise than control ventilation, reduces atrophy of respiratory muscles and the need for sedation and muscle relaxation and can be associated with pressure support ventilation.