Increasing the inspiratory time and I:E ratio during MV increased pulmonary permeability in 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, which 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. Albumin concentrations in bronchoalveolar lavage fluid (BALF) and plasma were determined. An increased albumin BALF/plasma ratio indicated enhanced lung permeability. n = 5 to 6 each group; ** < 0.01.