The present study had several aims: (1) In order to assess the consequences of MV properly, we established a set-up that permits the ventilation of mice under permanent monitoring of clinically relevant physiological parameters. (2) We used this set of parameters to define ventilatory conditions that guarantee stable lung mechanics, hemodynamics, acid base status and oxygenation over six hours. In particular, we studied the input impedance of the lung at low frequencies to distinguish mechanical properties of conductive airways and the distal lung [24] . (3) We investigated the physiological effects of recurrent RM on lung mechanics at two different tidal volumes (8 vs. 16 mL/kg) and at two different PEEPlevels (2 vs. 6 cmH 2 O). (4) Since inflammatory lung injury may occur even with 'non-injurious' ventilation [7, 8, 25] , we also assessed the extent of pulmonary inflammation, i.e. microvascular permeability, pulmonary sequestration of leukocytes, production of proinflammatory cytokines and lung histopathology. Our findings in healthy animals show that low V T ventilation will only maintain lung functions and gas exchange in a normal range if recurrent RM are used. In addition, recurrent RM reduced the extent of pulmonary inflammation, although mild inflammation was present in the lungs of all ventilated animals. The higher PEEP of 6 cmH 2 O was beneficial regarding lung mechanics, oxygenation and pulmonary inflammation. Thus, we suggest that a preferable ventilation strategy is one that combines low tidal volumes with sizable PEEP and recurrent recruitment manoeuvres.