title: Noninferiority of Inhaled Epoprostenol to Inhaled Nitric Oxide for the Treatment of ARDS.
abstract: BACKGROUND
  Inhaled nitric oxide and inhaled epoprostenol have been evaluated for the management of hypoxemia in acute respiratory distress syndrome, with clinical trials demonstrating comparable improvements in oxygenation. However, these trials have several limitations, making it difficult to draw definitive conclusions regarding clinical outcomes.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the noninferiority and safety of inhaled epoprostenol compared with inhaled nitric oxide in mechanically ventilated acute respiratory distress syndrome (ARDS) patients with a primary outcome of ventilator-free days from day 1 to day 28.
  
  
  METHODS
  This was a retrospective, noninterventional, propensity-matched, noninferiority cohort study. Propensity score for receipt of inhaled nitric oxide was developed and patients were matched accordingly using a prespecified algorithm. Secondary objectives included evaluating day 28 intensive care unit-free days, changes in PaO2/FiO2 ratio after inhalation therapy initiation, and hospital mortality. Safety endpoints assessed included hypotension, methemoglobinemia, renal dysfunction, rebound hypoxemia, significant bleeding, and thrombocytopenia.
  
  
  RESULTS
  Ninety-four patients were included, with 47 patients in each group. Patients were well-matched with similar baseline characteristics, except patients in inhaled nitric oxide group had lower PaO2/FiO2 ratio. Management of ARDS was similar between groups. Mean difference in ventilator-free days between inhaled epoprostenol and inhaled nitric oxide was 2.16 days (95% confidence interval = -0.61 to 4.9), with lower limit of 95% confidence interval greater than the prespecified margin, hence satisfying noninferiority. There were no differences in any secondary or safety outcomes.
  
  
  CONCLUSIONS
  Inhaled epoprostenol was noninferior to inhaled nitric oxide with regard to ventilator-free days from day 1 to day 28 in ARDS patients.
authors.affiliation: Cleveland Clinic, Cleveland, OH, USA ammarm@ccf.org.
authors.forename: Mahmoud A
authors.initials: MA
authors.lastname: Ammar
authors.affiliation: Cleveland Clinic, Cleveland, OH, USA.
authors.forename: Seth R
authors.initials: SR
authors.lastname: Bauer
authors.affiliation: Cleveland Clinic, Cleveland, OH, USA.
authors.forename: Stephanie N
authors.initials: SN
authors.lastname: Bass
authors.affiliation: Cleveland Clinic, Cleveland, OH, USA.
authors.forename: Madhu
authors.initials: M
authors.lastname: Sasidhar
authors.affiliation: Cleveland Clinic, Cleveland, OH, USA.
authors.forename: Rory
authors.initials: R
authors.lastname: Mullin
authors.affiliation: Cleveland Clinic, Cleveland, OH, USA.
authors.forename: Simon W
authors.initials: SW
authors.lastname: Lam
mesh_terms: D000280:Administration, Inhalation; D000368:Aged; D011464:Epoprostenol / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000008:administration & dosage*; D057216:Propensity Score; D012121:Respiration, Artificial; D012128:Respiratory Distress Syndrome / Q000188:drug therapy*; D012189:Retrospective Studies; D013997:Time Factors; D014665:Vasodilator Agents / Q000008:administration & dosage*; D015300:Ventilator Weaning
chemical_list: D014665:Vasodilator Agents; D009569:Nitric Oxide; D011464:Epoprostenol
keywords: ARDS; epoprostenol; hypoxemia; nitric oxide; pulmonary vasodilator