Ten patients with acute respiratory distress syndrome (ARDS) received in random order nitric oxide (NO) inhalation, aerosolized prostaglandin E(1) (PGE(1)), infusion of PCE(1), or no intervention. Inhalation of either aerosolized PCE(1) (10 +/- 1 ng/kg/min) or NO (7 +/- 1 ppm) reduced pulmonary vascular resistance (PVR) from 158 +/- 14 to 95 +/- 11 dyn.s/cm(5)/m(2) (NO) and 100 +/- 12 dyn.s/cm(5)/m(2) (aerosolized PGE(1)), and improved Pa(O2) from 78 +/- 3 to 96 +/- 5 mm Hg (NO) and 95 +/- 4 mm Hg (aerosolized PGE(1)) (p < 0.05), venous admixture (Q(VA)/Q(T)) from 45 +/- 2 to 36 +/- 2% (NO), and 36 +/- 2% (aerosolized PCE(1)) (p < 0.05), oxygen delivery (Do(2)) from 711 +/- 34 to 762 +/- 45 ml/min/m(2) (NO) and 780 +/- 46 ml/min/m(2) (aerosolized PGE(1)) (p < 0.05), and right ventricular ejection fraction (RVEF) from 32 +/- 6 to 37 +/- 5% (NO), and 36 +/- 4% (aerosolized PGE(1)) (p < 0.05) at a constant cardiac index (CI). Although infusion of PCE, (12 +/- 1 ng/kg/min) caused a similar reduction in PVR as aerosolized PGE(1) and NO inhalation, it improved RVEF and increased Cl but decreased Q(VA)/Q(T) and Pa(O2). These results suggest that in ARDS patients inhalation of aerosolized PGE(1) or NO in low concentrations equally improves PVR and gas exchange by selective vasodilation in ventilated areas.
