Prostacyclin in experimental septic acute respiratory failure

Manipulation of prostaglandins (PG) in animal models of sepsis and acute respiratory failure (ARF) is promising. Prostacyclin (PGI 2), a short-acting vasodilator, was evaluated in a porcine model of ARF produced by continuous infusion of live Pseudomonas aeruginosa (Ps.). Cardiopulmonary parameters were monitored in three groups of spontaneously breathing animals that received 0.1 μg PGI 2/kg/min begun 20 min after baseline (Group I); 2 × 10 8 Ps./20 kg/min (Group II); identical Ps. infusion and then PGI 2 begun at 20 min (Group III). The decrease in mean arterial blood pressure and cardiac index with Ps. infusion was improved by PGI 2 treatment. In Groups II and III, mean pulmonary artery pressure ( PAP ) doubled ( P < 0.005) and pulmonary vascular resistance (PVR) tripled ( P < 0.01) by 15 min. Both PAP and PVR were decreased significantly with PGI 2 treatment. In both Ps. groups, significant hypoxemia occurred. PGI 2 improves cardiac output and acts as a pulmonary vasodilator, but does not improve oxygenation in this porcine model of severe ARF.