Electrical Impedance Tomography and Lung Ultrasound Score in Early Prediction of Bronchopulmonary Dysplasia in Preterm and Very Low Birth Weight Infants.

104 preterm infants born between 26 and 32 weeks of gestational age and/or with a birth weight < 1500g (very low birth weight infants - VLBW) with respiratory distress syndrome (RDS). are enrolled in the study In non-invasive ventilation (nasal continuous positive airway pressure -nCPAP- or high flow nasal -HFNC-) at 72h of life.

The study will be conducted at the Neonatal Intensive Care Unit of the Fondazione Policlinico San Matteo IRCSS,Pavia, Italy; PI Dr. S. Ghirardello; Chief of NICU.. Participation at the study will not modify the standard clinical care. In particular, the data obtained from this study will not be used to change the clinical practice in use at the time of the study and the investigators will supervise the proper conduct of the research.Recruitment of patients will be consecutive and continuous through the project investigator in daily clinical practice, if the criteria for inclusion in the study will be met and after obtaining informed consent from the parents.

The study procedures follow the standard clinical practice at our Unit, inclusive of lung ultrasound (LUS). In addition, Electrical Impedance Tomography (EIT) will be performed.

Briefly, after stabilization in delivery room, the clinicians start nCPAP or HFNC and administer surfactant therapy, according to "European guidelines 2022" and standardized internal protocols. The surfactant therapy should be given early in the course of the disease. The suggested protocol would be to treat worsening babies with RDS when FiO2 > 0.30 on CPAP pressure ≥6 cm H2O or if lung ultrasound suggests surfactant need. Less invasive surfactant administration (LISA) is the current preferred method of surfactant administration for spontaneously breathing babies on CPAP. The decision to intubate and start endotracheal mechanical ventilation (MV) is based on the development of respiratory acidosis (pH < 7.20, pCO2 > 60-65mmHg) or severe apnea. While on MV, the SatO2 target was 90%-94%; pH is kept between 7.25 and 7.35, and pCO2 is maintained between 45 and 60mmHg as per local protocols. Infants will be extubated if mean airway pressure (MAP) < 8 cmH20, FiO2 < 0.30, and good respiratory drive is evident.

EIT ENLIGHT 2100 (Timpel®) is a bedside system that uses high-frequency, low-intensity electric signals to provide live images of the breathing lung showing pulmonary performance in real-time. The specific neonatal 16-electrode bands made of hypoallergenic material, soft and thin, will be applied to the chest at the nipple level and will be connected to the tomograph for 60 minutes. During each intervention period, four 10-minute EIT sequences are recorded and for each recording, the first 30 stable consecutive breaths of artefact-free tidal ventilation will be identified. EIT recordings will be made after allowing the infant to stabilize, and in supine position. The raw EIT data will be reconstructed according to standardized guidelines with an anatomically correct and customized human chest algorithm using the manufacturer's software package to exclude impedance variations outside the boundaries of the left and right lungs. Once reconstructed, each of the recordings will be manually examined. Functional EIT images of the current volume distribution will be created, and data extracted from the entire lung, the right and left lungs.