Activation of the pulmonary arachidonic acid system and its consequences for hemodynamics and fluid balance.

The pulmonary vasculature and perivascular tissue is able to generate arachidonic acid metabolites with strong effects on vascular tone and permeability. Stimulators of the pulmonary arachidonic acid metabolism, which represents a highly potent mediator system, are components of the classical cascade systems, bacterial toxins, hypoxia, and a variety of other physiological and non-physiological factors. Upon excessive stimulation, the pulmonary circulation responds with vasoconstriction and extravasation. Since granulocytes are always involved, their contribution to the resulting vascular effects has to be considered.