Clinical Research Directory

Inclusion Criteria: * Corrected gestational age (postmenstrual age) \> 34 6/7 weeks * postnatal age ≤ 28 d * on respiratory support with invasive mechanical ventilation, non-invasive ventilation, CPAP or high flow nasal cannula (defined as flow rates ≥ 2 LPM with a humidifier), inspired oxygen concentration, FiO2 ≥ 0.3 * and echocardiography shows any finding suggestive of PH (or score \> 0 for PH in table 2). * Infants with congenital diaphragmatic hernia (CDH), Down syndrome, hypoxic ischemic encephalopathy (HIE) on therapeutic hypothermia and patent ductus arteriosus (PDA), patent foramen ovale/atrial septal defect (PFO/ASD) and ventricular septal defect (VSD) (single or multiple) \< 2 mm can be included in the study. Exclusion Criteria: * \< 32 weeks gestation at birth (31 6/7 or lower) * Weight \< 2000 g at the time of enrollment * Severe HRF with OI \> 35 or SpO2 \< 75% on FiO2 = 1.0 on mechanical ventilation for \> 60 minutes in spite of correction of reversible factors such as pneumothorax * A condition or congenital anomaly known to be lethal (high likelihood of death during infancy) - e.g., trisomy 18 or trisomy 13 * Congenital heart disease other than ASD/PFO, PDA or VSD (single or multiple defects) \< 2 mm.