Iloprost Improves Gas Exchange in Patients with Pulmonary Hypertension and ARDS

ABSTRACT: 

AIMS AND OBJECTIVES:  We hypothesized that nebulized iloprost would improve ventilation perfusion matching in patients with pulmonary hypertension and acute respiratory distress syndrome (ARDS) as reflected by an improved PaO₂/F_IO₂ ratio and PaO₂ without adversely affecting lung mechanics or systemic hemodynamics.

METHODS:  ARDS patients with pulmonary hypertension were enrolled. With constant ventilator settings, hemodynamics, airway pressures and gas exchange measured at baseline were compared to values 30 min after 10 mcg nebulized Iloprost, and again 30 min after a second dose of 20 mcg of iloprost and finally 2 h after the second dose. The primary outcome variable was PaO2 while secondary outcomes were PaO₂/F_IO₂ ratio, mean arterial BP, and lung compliance ventilatory equivalents for O₂ and CO₂.

RESULTS:  After informed consent was obtained 20 patients (9 male and 11 female, median age 59 ((IQR 44 to 66)) years, with ARDS were enrolled. Baseline PaO₂ improved from 82(±13) mmHg to 100(±25) and 100(±25) mmHg after the 1^st and 2^nd doses of iloprost respectively, while, PaO₂/F_IO₂ ratio of 177(±60) improved to 213(±67) and 212(±70) (all p<0.01). PaCO₂, peak and plateau airway pressures, systemic blood pressure and heart rate were not significantly changed after iloprost.

CONCLUSIONS:  The improvement in gas exchange without any detrimental effects on pulmonary mechanics or systemic hemodynamics suggests nebulized iloprost may be a useful therapeutic agent to improve oxygenation in patients with ARDS.ClinTrials.gov NCT01274481