In normal rabbits subjected to saline lavage, injurious mechanical ventilation was shown to significantly increase lung neutrophil accumulation and chemi- luminescence (an indicator of neutrophil priming) (11, 12), as well as bronchoalveolar lavage (BAL) levels of inflammatory mediators (platelet activating factor and thromboxane-B 2 [13]) and expression of tumor necrosis factor-alpha (TNF- a ) by al- veolar macrophages (14). Similarly, in rat lungs ventilated ex vivo increased BAL concentrations of a number of cytokines (including TNF-