Here is the design of a clinical trial:

Official Title: Efficacy and Safety of 72-hour Infusion of Prostacyclin (1 Nanogram(ng)/ Kilo(kg)/Minute(Min)) in Patients With COVID-19 Induced Pulmonary Endotheliopathy

Included conditions:
- COVID-19
- Respiratory Failure

Study Armgroups:
- {'label': 'Iloprost', 'type': 'EXPERIMENTAL', 'description': 'Patients randomized to active treatment (n=40 patients) will receive continuous infusion of iloprost for 72 hours after inclusion or until discharge to ward or death, whichever comes first.', 'interventionNames': ['Drug: Iloprost']}
- {'label': 'Isotonic saline', 'type': 'PLACEBO_COMPARATOR', 'description': 'Patients randomized to placebo treatment (n=40 patients) will receive continuous infusion of placebo for 72 hours after inclusion or until discharge to ward or death, whichever comes first.', 'interventionNames': ['Drug: Isotonic saline']}

Interventions:
- {'type': 'DRUG', 'name': 'Iloprost', 'description': 'Continuously infusion for 72 hours at 3 ml/hours. Treatment dose 1 ng/kg/min', 'armGroupLabels': ['Iloprost'], 'otherNames': ['Ilomedin']}
- {'type': 'DRUG', 'name': 'Isotonic saline', 'description': 'Continuously infusion for 72 hours at 3 ml/hours', 'armGroupLabels': ['Isotonic saline']}

Primary Outcomes:
- {'measure': 'Mechanical ventilation free days', 'description': 'Days alive without mechanical ventilation in the ICU within 28 days', 'timeFrame': 'Until ICU discharge, maximun 28 days after randomization'}

Please estimate the sample size based on the assumption: 
Not specified
Numbers to be randomised (sample size)
          Forty patients are planned to be randomized to each group, with a total sample size of 80 patients.