abstract:Inverse ratio ventilation (IRV) is not necessarily a mode of mechanical ventilation though it may be referred to as such. IRV is a strategy (method or style) of ventilating the lungs in such a way that some inspired air is not allowed to be exhaled, creating intrinsic positive-end expiratory pressure (autoPEEP) and allowing for a constant inflation of the lungs, ensuring they remain "recruited" (meaning they participate in gas exchange and are not allowed to deflate to get stuck together or tighten up).