Fast Assessment of Surfactant Deficiency in Preterm Infants to Speed up Treatment - Validation Study

Included infants will have a gastric aspirate sampled via an NG tube at birth. This sample will be analyzed to determine the LS-ratio The LS-ratio will retrospectively be compared to RDS development and need for surfactant treatment to establish the cut-off ratio for LS-ratio with respect to surfactant treatment.