Three levels of shunting were induced in anesthetized pigs by blocking the airways with steel beads. Shunt fractions ranged from less than 0.3 to greater than 0.5. Treatment with DDFPe was given in 1-3 infusions 3-5 hours apart. Minutes after the infusions started, a rise in arterial oxygen tension was observed in all animals in all groups. These results suggest that DDFPe infusion in combination with 02 breathing could be a valuable treatment to mitigate hypoxemia in shunts of different etiologies.