TY - JOUR T1 - Physical and biological triggers of ventilator-induced lung injury and its prevention JF - European Respiratory Journal JO - Eur Respir J SP - 15s LP - 25s DO - 10.1183/09031936.03.00021303 VL - 22 IS - 47 suppl AU - L. Gattinoni AU - E. Carlesso AU - P. Cadringher AU - F. Valenza AU - F. Vagginelli AU - D. Chiumello Y1 - 2003/11/16 UR - http://erj.ersjournals.com/content/22/47_suppl/15s.abstract N2 - Ventilator-induced lung injury is a side-effect of mechanical ventilation. Its prevention or attenuation implies knowledge of the sequence of events that lead from mechanical stress to lung inflammation and stress at rupture. A literature review was undertaken which focused on the link between the mechanical forces in the diseased lung and the resulting inflammation/rupture. The distending force of the lung is the transpulmonary pressure. This applied force, in a homogeneous lung, is shared equally by each fibre of the lung's fibrous skeleton. In a nonhomogeneous lung, the collapsed or consolidated regions do not strain, whereas the neighbouring fibres experience excessive strain. Indeed, if the global applied force is excessive, or the fibres near the diseased regions experience excessive stress/strain, biological activation and/or mechanical rupture are observed. Excessive strain activates macrophages and epithelial cells to produce interleukin‐8. This cytokine recruits neutrophils, with consequent full-blown inflammation. In order to prevent initiation of ventilator-induced lung injury, transpulmonary pressure must be kept within the physiological range. The prone position may attenuate ventilator-induced lung injury by increasing the homogeneity of transpulmonary pressure distribution. Positive end-expiratory pressure may prevent ventilator-induced lung injury by keeping open the lung, thus reducing the regional stress/strain maldistribution. If the transpulmonary pressure rather than the tidal volume per kilogram of body weight is taken into account, the contradictory results of the randomised trials dealing with different strategies of mechanical ventilation may be better understood. ER -