Lung immaturity is a major issue in neonatal unit.The surfactant administration improves the pulmonary prognosis in premature infants with hyaline membrane disease who escape continuous positive airway pressure (CPAP).

This surfactant had been administered at 5h25min of life in Saint Etienne from 2016 to 2019.

Studies suggest that the earlier the surfactant is administered, the more it can reduce the rate of bronchodysplasia and mortality. And some studies show a pulmonary ultrasound could help to administrate the surfactant earlier This is why a new faster strategy for diagnosing preterms needing surfactant will be usefulness and have been done in Saint-Etienne since 2021 thanks to a ultrasound score (LUS).

This current study analyzes the impact of early Lungs Ultrasounds which use a semi-quantitative assessment : the Lung Ultrasound Score (LUS), in preterms <33 weeks on the time to surfactant administration.

The current hypothesis is that Lung Ultrasound can increase the number of preterms with surfactant replacement within the first 3 hours of life.

This is a prospective, comparative, observational trial between two different cohorts : the last 6 months of 2019 (without Score LUS) versus the first 6 months of 2021 (with Score LUS).

Inclusion Criteria:

• newborns <33 weeks old
• born at the Saint Etienne University Hospital
• respiratory distress syndrome

Exclusion Criteria:

• chromosomal abnormality,
• multi-polymalformations syndrome,
• congenital pulmonary disease,
• septic shock,
• congenital lung infection,
• meconium inhalation,
• pneumothorax
• conditions requiring surgery in the first week of life.

preterm newborns < 33 weeks with Respiratory Distress Syndrom needed surfactant administration

Date of birth from 01/08/19 to 31/12/19 and from 01/01/21 to 30/06/21