BACKGROUND: Epoprostenol (Flolan), an inhalational epoprostenol vasodilator, increases pulmonary arterial flow and decreases pulmonary pressures, thereby improving gas exchange and arterial oxygenation. We evaluated the benefits of inhaled epoprostenol as a less expensive alternative to nitric oxide in ventilated surgical intensive care patients with severe hypoxemia. METHODS: After institutional review board approval was obtained, the records of mechanically ventilated surgical intensive care unit patients who received epoprostenol as a therapy for severe hypoxia (SaO 2 < 90%) in a tertiary care referral center were retrospectively reviewed. Initial PaO 2/FIO 2 (P/F) ratio and oxygen saturation were compared with values at 12 and 48 hours after the administration of epoprostenol. One-way repeated-measures analysis of variance compared improvements in oxygenation. Further subgroup analyses evaluated differences among trauma, nontrauma patient subgroups, time to initiation of epoprostenol, and age. RESULTS: During a 20 month-interval beginning February 2009, 36 patients (23 trauma and 13 nontrauma; age, 15-80 years) were treated. Epoprostenol significantly improved both P/F ratio and oxygen saturation in both trauma and nontrauma patients. Therewas no difference between subgroups. Larger improvements in P/F ratiowere seen when epoprostenolwas started within 7 days. Response between age groups did not differ significantly. Subgroup analysis of mortality (trauma, 60.9% vs. nontrauma, 61.5%) failed to show any differences. CONCLUSION: Treatment with inhaled epoprostenol improved gas exchange in severely hypoxemic surgical patients. Earlier intervention (within 7 days of intubation) was more efficacious at improving oxygenation. Copyright © 2012 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.