EXTERNAL NEGATIVE PRESSURE DURING LISA

The goal of this clinical trial is to evaluate the feasibility, safety, and preliminary effectiveness of applying external continuous negative pressure (ECNP) during less invasive surfactant administration (LISA) in preterm infants with respiratory distress syndrome (RDS). It will also assess whether ECNP can improve surfactant distribution and reduce procedural complications. The main questions it aims to answer are: Does ECNP during LISA improve surfactant distribution and oxygenation in preterm infants with RDS? Does ECNP reduce the occurrence of complications such as desaturation, bradycardia, or apnea during the procedure? Does ECNP reduce the need for repeated surfactant administration? Researchers will evaluate ECNP combined with LISA in preterm infants on HFNC or CPAP to see if it improves outcomes compared to standard methods. Participants will: Receive LISA with ECNP support via a soft thoracoabdominal cuirass Be monitored for procedural complications like desaturation, bradycardia, or apnea Have their oxygenation levels, surfactant distribution, and need for repeated surfactant doses assessed Primary Outcome: The procedure will be considered safe if no more than 20% of participants experience serious adverse events, such as apnea requiring positive pressure ventilation or persistent desaturation. Secondary Outcomes: Completion of LISA without interruption due to complications Reduction of FiO₂ to ≤0.25 within 3 hours post-surfactant administration Avoidance of repeated surfactant doses via the INSURE method