Clinical Fellow The Hospital for Sick Children TORONTO, Ontario, Canada
Background: Inhaled nitric oxide (iNO) is the standard of care management for persistent pulmonary hypertension of neonate (PPHN). Its use is associated with a reduction in mortality or need for extracorporeal membrane oxygenation (ECMO) use. There is a paucity of literature with regard to clinical and echocardiographic predictors of response and outcomes in neonates who are iNO non-responders [improvement in oxygenation indices less than 20% above baseline, within 60 min of initiation] Objective: The primary objective is to investigate the key echocardiographic and clinical indices in term neonates with PPHN that are iNO non-responders and its association with survival. The secondary objective is to investigate the association between iNO non-responders and the short and long-term outcomes Design/Methods: This 9.5-year (01/01/2013 to 30/06/2022) single-centre retrospective cohort study is conducted at the Hospital for Sick Children. We will include term infants (37-42 weeks gestational age) with significant hypoxic respiratory failure (FiO2 ≥ 0.6 pre-iNO despite invasive mechanical ventilation), exposed to iNO < 72 hours age with the availability of one echocardiography in that time period confirming PPHN. Infants with significant congenital heart defects (except patent ductus arteriosus or patent foramen ovale or ≤2mm ventricular septal defect), or chromosomal anomaly will be excluded. The primary outcome is death within 14 days of illness. Secondary outcomes are i) survival to discharge, ii) need for ECMO and neurodevelopmental outcomes at 18-24 months corrected GA. The cohort will be divided into those iNO responders and non-responders. Intergroup comparison of baseline demographics, echocardiographic indices and outcomes will be performed. A paired t-test (continuous variables with normal distribution) and Chi-square or Fisher’s exact test (categorical variables) will be used. Multivariate regression analysis will be performed to identify factors independently associated with the primary outcome. IRB approved (1000081183). Data collection by 31/01/2024. Analysis by 25/02/2024
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