Increasing the inspiratory time and I:E ratio during MV increased VILI. Mice were mechanically ventilated for 4 hours with either low tidal volume (LVT 9 ml/kg) or high tidal volume (HVT 34 ml/kg) and an inspiratory/expiratory ratio of 1:2 or 1:1, respectively. An alternative end point was defined as decreasing of mean arterial blood pressure below 40 mm Hg, as this predicts death with certainty in this model. Controls (ctr) were subjected to LVT 1:2 ventilation only during operation and were killed before the 4-hour ventilation protocol started. Ctr and LVT groups showed no signs of lung injury macroscopically. HVT 1:2 revealed only subtle macroscopic signs of injury, whereas the HVT 1:1 group showed massive edema formation. Representative images from 13 to 14 animals per group are shown.