Increasing the inspiratory time and I:E ratio increased number of pulmonary and blood neutrophils 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 illed before the 4-hour ventilation protocol started. The fractions of neutrophils among leukocytes in the BALF (A) and in the blood (B) at the end point of the experiment are shown. n = 5 to 6 each group; *P < 0.05, **P < 0.01, ##P < 0.01 versus all.