(No Copyright)Pathogenesis of ARDS
1) High permeability edema, visible on the chest x-ray. It also inhibits surfactant function (especially fibrin monomers).
2) Epithelial injury also impairs new surfactant synthesis.
3) Inflammation may exacerbate the injury because of release of oxidants and lysosomal enzymes from activated leukocytes. Lung compliance (delta V) / (delta P) is decreased because many airspaces contain edema (and hence cannot accept air) and because abnormally high surface tension counteracts the negative intrapleural pressure.
