Fig. 1. Pulmonary ventilation and perfusion plotted against 50 lung compartments with different ventilation perfusion (˙Va/˙Q) ratios in one representative animal from each group 30 min after untreated acute lung injury (Control), administration of 25 ng · kg−1· min−1inhaled prostacyclin (Prostacyclin), administration of 1 μg · kg−1· min−1intravenous almitrine (Almitrine), and administration of 25 ng · kg−1· min−1inhaled prostacyclin in combination with 1 μg · kg−1· min−1intravenous almitrine (Combined Prostacyclin and Almitrine). Shunt = blood flow to lung regions with ˙Va/˙Q = 0; Dead space ventilation (˙VD/˙VT) = ventilation to lung regions with ˙Va/˙Q greater than 100.