The role of type III pulmonary surfactants in the pathogenesis of neonatal respiratory distress syndrome (NRDS)

Background and Aim: Neonatal Respiratory Distress Syndrome (NRDS), often caused by surfactant deficiency, is a major concern in preterm infants. This study aimed to explore the relationship between SP-A and SP-D levels and NRDS severity. Methods: A total of 100 preterm neonates diagnosed with NRDS were enrolled and categorized into mild, moderate, and severe groups. Data on surfactant therapy, including the timing and number of doses, were collected, and the response to therapy was assessed by monitoring ventilatory support and stability of oxygenation (FiO2 < 0.30 for 12 h). Results: SP-A and SP-D levels were significantly lower in the severe group compared to the mild and moderate groups (P < 0.01). Lower levels of these proteins were associated with higher inflammatory markers (CRP and IL-6), more surfactant doses, longer mechanical ventilation, and extended NICU stays (P < 0.01). Logistic regression revealed that lower SP-A (OR = 0.86) and SP-D (OR = 0.83) were significant predictors of NRDS severity. ROC curve analysis showed AUC values of 0.85 for SP-A and 0.81 for SP-D, highlighting their potential as biomarkers. Conclusion: SP-A and SP-D play a crucial role in NRDS pathogenesis and could serve as biomarkers to assess disease severity and guide treatment.