Inhaled prostacyclin (PGI2) versus inhaled nitric oxide in adult respiratory distress syndrome.

Abstract

Inhalation of nitric oxide (NO) and prostacyclin (PGI2) may induce selective pulmonary vasodilation and-by improving ventilation-perfusion ratio in ventilated areas of the lung-increase Pao2 in patients with acute lung injury. To assess the therapeutic efficacy of both compounds, dose-response curves were established in patients with adult respiratory distress syndrome (ARDS). Patients received both PGI2 (doses of 1, 10, and 25 ng/kg/min) and NO (concentrations of 1, 4, and 8 ppm). Cardiorespiratory parameters were assessed at control, at each drug concentration, and after withdrawal of NO and PGI2. PGI2 resulted in a significant, dose-dependent and selective reduction of pulmonary artery pressure (PAP) from 35.1 +/- 6.3 mm Hg at control to 33.1 +/- 4.8 (1 ng/kg/min), 31.3 +/- 4.8 mm Hg (10 ng/kg/min) and 29.6 +/- 4.5 mm Hg (25 ng/kg/min), respectively. Inhaled NO reduced PAP from 34.5 +/- 5.6 to 32.1 +/- 5.9 mm Hg at 4 ppm, and to 31.8 +/- 6.1 mm Hg at 8 ppm, respectively, with no effect at 1 ppm. Pao2/Flo2 ratio increased from 105 +/- 37 to 125 +/- 56 mm Hg (range of increase: 0 to 57 mm Hg) at PGI2 10 ng/kg/min and to 131 +/- 63 mm Hg (range: -5 to 89 mm Hg) at 25 ng/kg/min with no effect at 1 ng/kg/min. NO improved Pao2 (e.g., from 116 +/- 47 to 167 +/- 86 mm Hg at 8 ppm) and reduced intrapulmonary shunt at all doses tested. We conclude that both inhaled PGI2 and NO may induce selective pulmonary vasodilation and increase Pao2 in severe ARDS.

Inhaled Iloprost for Severe Pulmonary Hypertension

“…5,6 Designed to combine the beneficial effects of prostacyclin with those of an inhalational application, aerosolized prostacyclin was found to be a potent pulmonary vasodilator in patients with acute respiratory failure, exerting preferential vasodilatation in well-ventilated lung regions. [7][8][9][10] Similar results were obtained in spontaneously breathing patients who had lung fibrosis and severe pulmonary hypertension. 11 Iloprost is a stable analogue of prostacyclin that is associated with a longer duration of vasodilatation.…”

Predictors of Outcome in 216 Subjects With ARDS Treated With Inhaled Epoprostenol

“…34 Although we know that inhaled epoprostenol can improve oxygenation and reduce shunt 11 in patients with ARDS, there are no compelling data that its routine use will improve survival. 6,22,23,34 Moreover, there are virtually no data to guide clinicians in terms of which patients with ARDS are more likely to benefit from the administration of inhaled epoprostenol. Nevertheless, our findings suggest that the use of inhaled epoprostenol in patients with ARDS associated with trauma, greater body mass index, and more robust improvements in oxygenation is more likely to result in both hospital and 90-d survival.…”

Circulatory Effects of Inhaled Iloprost in the Newborn Preterm Lamb

“…prostacyclin was found, although a more pronounced vasodilatation occurred during long-term therapy (26). In one study, iloprost was more effective in decreasing PH than iNO and sildenafil (27), whereas in another iNO was more effective than inhaled prostacyclin (28). For acute PH, e.g.…”