Reversal of oleic acid-induced respiratory distress by prostacyclin (PGI2)

The effects of Prostacyclin (PGI2) on gas exchange were investigated in 13 adult mongrel dogs with acute pulmonary edema induced by oleic acid (0.09 ml/kg). The time course of changes in gas exchange was measured during spontaneous ventilation with room air. In the Control group, with oleic acid induced respiratory distress, there were marked decreases in arterial PO2 and PCO2, and marked increases in respiratory frequency, expired minute volume, alveolar (end tidal)-arterial PO2 difference, arterial-alveolar (end tidal) PCO2 difference and physiological dead space to tidal volume ratio. In the Test group, respiratory distress was also induced by the oleic acid injection, however, subsequent infusion of PGI2 (200 ng/kg/min) reversed the values of these parameters, which were significantly different from those in the Control group. The results suggest that PGI2 has a protective action against impairment of gas exchange in the presence of increased pulmonary vascular permeability.