The most important causes of ALI/ARDS are sepsis, pneumonia, major trauma, pulmonary aspiration, near drowning, burns, inhalation of toxic gases (e.g. ammonia), fat embolism, amniotic fluid embolism, eclampsia, drug intoxication (e.g. aspirin), radiation injury and mechanical ventilation. Cox and colleagues have demonstrated in an ovine model of ARDS that there is intense acute inflammation in the trachea and bronchi from 3 to 48h after injury, with accumulation of neutrophils, fibrin and other plasma proteins, and mucus in airway lumens. Immunostaining for multiple cytokines (interleukin-8 (IL-8), IL-1beta, IL-1alpha, tumor necrosis factor-alpha (TNF-alpha), and vascular endothelial growth factor (VEGF)) are found in airway mucous glands, and the release of cytokines into the airway lumen are considered potentially highly significant in the progression of injury.