Cardiorespiratory Effects of Nasal High Frequency Ventilation in Neonates

The aim of the present work is to study the cardio-respiratory effects of non-invasive ventilation (nasal high-frequency ventilation and nasal CPAP) as an initial therapy of respiratory distress in moderate and late preterm infants as regard: I. Primary outcomes: * Duration of the non- invasive respiratory support. * Need of invasive ventilation in the first 72 hours. * Short-term complications such as air leak syndromes, pulmonary hemorrhage, intraventricular hemorrhage, and nasal trauma. II. Secondary outcomes: * Need for surfactant administration. * Days on invasive mechanical ventilation. * Days on supplemental oxygen. * Duration of hospital stay. * Mortality rate. III. Hemodynamic changes during the period of non-invasive ventilation.