Role of prostaglandin E1 in reducing pulmonary vascular resistance in an experimental model of acute lung injury. To determine the role and efficacy of prostaglandin E1 (PGE1) on the cardiopulmonary derangements induced by glass bead embolism, two studies were performed. In the first study, a dose response of PGE1 was tested in six animals that were first embolized with sufficient glass beads to double the pulmonary artery pressure (PAP). This study demonstrated that PGE1 reduced PAP and cardiac output by a preload-mediated mechanism, as evidenced by a reduction in the right ventricular (RV) end-diastolic segment length, at doses of 15 and 30 ng/kg.min. The second study was performed in two groups of animals, the control group (n = 6), and the treated group (n = 6), which were given PGE1 at 15 ng/kg.min after the PAP had been doubled by glass bead embolism. RV preload was kept constant. This study demonstrated that there was no difference in pulmonary vascular resistance between either the treated group or the control group. There were no other significant differences between the two groups. The results of both of these studies suggest that there is little afterload reducing effect of PGE1 in this model and at these dose ranges. Part of the mechanism of PGE1 that improves pulmonary edema and gas exchange may be the reduction of filtration surface area and hydrostatic pressures in the lungs. 