Inhaled nitric oxide (iNO) selectively reduces pulmonary vascular resistance and pulmonary arterial pressure without affecting systemic arterial pressure.1 Premature infants with respiratory distress syndrome (RDS) may have elevated pulmonary vascular resistance, which may negatively affect the afterload-sensitive premature right ventricle, diminishing cardiac output. To date, no large study has been performed evaluating the acute haemodynamic effects of iNO in premature infants.

This is a prospective observational study on 39 infants in our neonatal intensive care unit investigating the effects of early iNO in premature infants with mild-to-moderate RDS. The demographics of this infant group were the following: gestational age was 26.3±1.9 (SD) weeks, birth weight was 0.914±0.21 kg and hours of life at iNO administration was 53.2±21 h. Fraction of inspired oxygen (FiO_{2 …}