Pulmonary Hypertension / High Frequency / Magnesium / Nitric oxide / INTENSIVE CARE / Cohort Study / Length of Stay / Einstein / Clinical Data / Neonatal Intensive Care Unit / Hypoxic- Ischemic Encephalopathy / Cohort Study / Length of Stay / Einstein / Clinical Data / Neonatal Intensive Care Unit / Hypoxic- Ischemic Encephalopathy