There is an increasing demand for mechanical ventilation of mice, not only in pulmonary research, but also in many other areas such as neurology [26] , imaging [27] or cardiovascular research [28] . Monitoring of pulmonary and vital parameters is an essential prerequisite for correct interpretation of data from such models. The present study indicates that the general notion according to which low tidal volumes and sizable PEEP levels are preferable is -at least in healthy mice -only true when repetitive recruitment manoeuvres are applied.