547 - Timing and Dosing of Surfactant Administration in Preterm Infants with Respiratory Distress Syndrome: A Retrospective Chart Review

Publication Number: 3528.547

Ann Chacko, Tufts University School of Medicine, burlington, MA, United States; Neha Chaudhary, Tufts Childrens Hospital, westwood, MA, United States; Indrani Bhattacharjee, Tufts University School of Medicine, Boston, MA, United States

Background: Respiratory distress syndrome (RDS) is a major cause of morbidity in preterm neonates and is commonly treated with surfactant administration. Despite its proven efficacy, variation exists in timing, dosing and indications for surfactant administration across NICUs. Understanding local practices is imperative to standardize care and support future studies integrating bedside tools like lung point-of-care ultrasound.

Objective: Evaluate surfactant timing in preterm neonates with RDS and assess associations with respiratory severity scores (RSS) (RSS = Mean airway pressure (MAP) x Fraction inspired oxygen (FiO2)) and clinical outcomes including duration of respiratory support and need for re-dosing of surfactant.

Design/Methods: This retrospective study included neonates < 33 weeks gestation admitted to our Level III NICU (January 2024 to January 2025) with RDS who received at least one dose of surfactant. Infants with major congenital anomalies, death before surfactant, or prior treatment at another institution were excluded. Data were analyzed using descriptive and nonparametric statistics.

Results: Of 134 neonates (mean gestational age 29.5 weeks; birth weight 1287 g), 58 (43%) received at least one dose of surfactant . The median timing of the first dose was 2 h and second was 30 h with corresponding median RSS of 2.8 and 3.1 (Table 1). Across all gestational ages, early surfactant administration ( < 6 h) and single-dose response were associated with shorter mechanical ventilation times (Figure 1). Higher gestational age and birth weight were strongly correlated with shorter mechanical ventilation and NIPPV/CPAP duration, while more premature infants required prolonged support (Figure 2). In addition, RSS at surfactant administration correlated positively with FiO2 and MAP, supporting its validity as a respiratory severity index (Figure 2).

Conclusion(s): Early surfactant administration across all gestational age strata was associated with shorter respiratory support duration. More premature and lower birth weight neonates exhibited higher RSS and longer duration of respiratory support. These findings highlight the importance of timely surfactant therapy and support initiatives to standardize RDS management. Notably in this unit, surfactant timing and re-dosing were closely correlated with respiratory severity (RSS) rather than gestational age, reflecting a physiology-guided, individualized approach unlike most units. This distinction underscores a shift toward dynamic physiology-informed care that aligns with our evolving point-of-care ultrasound and physiology based NICU practice.

Table 1: Demographic and clinical parameters


Figure 1: Impact of surfactant timing and dosing on respiratory outcomes.
Earlier surfactant administration ( <6 h) and single-dose response were associated with shorter durations of mechanical ventilation across all gestational age strata ( <25, 25-28, >28 weeks). These findings suggest that treatment timing and re-dosing, rather than maturity alone, are key modifiable determinants of respiratory outcomes in preterm infants.

Figure 2: Bubble correlation map of maturity, surfactant timing, and respiratory outcomes (Spearman correlations)
Spearman correlation coefficients (ρ) are displayed as a bubble matrix for infants who received surfactant (n = 58). Bubble color indicates direction of association (red = positive, blue = negative) and bubble size reflects correlation strength. Birth gestational age and birth weight were strongly negatively correlated with duration of mechanical ventilation and NIPPV/CPAP, indicating that more premature, smaller infants required prolonged support. RSS at the time of surfactant administration correlated positively with FiO₂ and MAP, validating RSS as an index of respiratory severity. Later timing of surfactant and second dosing showed weak positive correlations with longer ventilation durations.