Surfactant retreatment in very preterm infants with respiratory distress syndrome: an observational cohort study

Background: Data on surfactant retreatment in preterm infants with respiratory distress syndrome (RDS) are limited, and international guidelines do not provide specific recommendations on this issue. The objective of this study was to evaluate the effectiveness of surfactant retreatment in very preterm infants (VPI). Methods: We retrospectively studied 140 VPI born at 23+0-29+6 weeks of gestation from January 2018 to June 2024 requiring surfactant treatment. Peripheral oxygen saturation/fraction of inspired oxygen (SpO2/FiO2) and arterial/alveolar partial pressure of oxygen (a/APO2) ratios were calculated prior to and following administration of the first and second doses of surfactant. Demographic and clinical features of infants receiving a single dose were compared with those of infants requiring multiple doses. Results: Fifty-four (39%) infants received one dose of surfactant and 86 (61%) multiple doses. SpO2/FiO2 and a/APO2 ratios improved significantly after administration of both the first and second doses of surfactant. Logistic regression analysis demonstrated that the SpO2/FiO2 ratio before the first dose of surfactant (odds ratio 0.994, 95% CI: 0.989-0.999, P=0.047) was inversely correlated with the need for a second dose of surfactant. Conclusions: The first and second doses of surfactant were effective in improving SpO2/FiO2 and a/APO2 ratios in VPI with RDS. Low SpO2/FiO2 ratios prior to the first surfactant dose may identify infants likely to require multiple surfactant doses. These results support the importance of further studies aimed at standardizing the treatment with multiple doses of surfactant.