Current evidence suggests that noninvasive positive pressure ventilation (NIPPV) is more effective than continuous positive airway pressure (CPAP) in preventing respiratory failure in preterm infants with respiratory distress syndrome (RDS), both as initial and post-extubation support. NIPPV may be delivered in synchronized (sNIPPV) or non-synchronized (nsNIPPV) modes, with sNIPPV offering clear benefits by coordinating support with the infant's own breathing. Recent studies indicate sNIPPV is superior to nsNIPPV in preventing respiratory failure, though the intrapulmonary mechanisms behind this advantage remain unclear. To address this, the present study uses Electrical Impedance Tomography (EIT) to evaluate how lung volume changes during different types of breaths and ventilator inflations - spontaneous breaths, synchronized inflations, non-synchronized inflations, and backup inflations - in preterm infants receiving sNIPPV.