Effects of aerosolized prostacyclin in severe pneumonia. Impact of fibrosis.

The effects of aerosolized prostaglandin (PG) I2 on gas exchange and hemodynamics were investigated in patients ventilated mechanically because of severe community-acquired pneumonia. Group A were patients without preexisting lung disease (n = 6), and Group B were those with underlying chronic fibrotic interstitial lung disease (n = 6). Ventilation-perfusion distribution was assessed by the multiple inert gas elimination technique. In Group A, low doses of aerosolized PGI2 (mean, 6.6 +/- 3.0 ng/kg/min) sufficed to decrease the mean pulmonary artery pressure (Ppa) from 35.0 +/- 1.5 to 31.0 +/- 1.6 mm Hg (p < 0.05), to improve the ratio of arterial oxygen to the fraction of inspired oxygen (PaO2/FIO2 increase from 100 +/- 18 to 134 +/- 18; p < 0.05), and to decrease intrapulmonary shunt (36.9 +/- 4.7 to 27.5 +/- 4.5%; p < 0.05). Systemic arterial pressure (Psa) and cardiac output remained unchanged. In Group B, aerosolized PGI2 was ineffective in doses less than 10 ng/kg/min. A dosage of 33.6 +/- 12 ng/kg/min reduced Ppa (38.0 +/- 2.4 to 30.8 +/- 2.1 mm Hg; p < 0.05), but it also decreased Psa (80.3 +/- 3.6 to 71.3 +/- 4.7 mm Hg; NS) and PaO2/FIO2 (73.8 +/- 6.6 to 65.5 +/- 6.8 mm Hg; p < 0.05) values and increased intrapulmonary shunt (44.7 +/- 3.0 to 49.4 +/- 5.0%, NS). After withdrawal of the PGI2 aerosol, all gas exchange and hemodynamic changes returned to preaerosol baseline values within 60 min in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)