Choosing a Right Surfactant for Respiratory Distress Syndrome Treatment

Respiratory distress syndrome (RDS) is the most common cause of respiratory insufficiency in preterm infants, especially those born at <30 weeks of gestation. Continuous positive airway pressure has been used since the 1970s as a primary mode of treatment for RDS. Surfactant therapy became available in the 1980s and has become the standard care for infants with or at risk for RDS. Surfactant therapy has been shown to decrease air leaks, neonatal and infant mortality as well as cost among survivors. Natural surfactants derived from animal sources containing surfactant proteins B (SP-B) and C (SP-C) as well as synthetic surfactants with functional SP-B- or SP-C-like protein mimics have been extensively evaluated in preterm neonates with or at risk for RDS. Evidence from randomized controlled trials indicates that treatment with natural surfactants results in faster weaning of supplemental oxygen and mean airway pressure, decreased duration of mechanical ventilation, and decreased mortality when compared to synthetic surfactants. Furthermore, at the present time, there are no approved synthetic surfactants available for use in preterm infants. Beractant, calfactant and poractant alpha are the three commonly used natural surfactants worldwide. Comparative studies including prospective randomized trials as well as large retrospective studies have shown significant differences in outcome and cost among these three natural surfactants. Of the eight prospective, randomized controlled trials and two retrospective studies involving the natural surfactant preparations, treatment with poractant alpha resulted in a significantly decreased mortality, decreased need for additional doses, faster weaning of oxygen and reduced hospital costs when compared to treatment with beractant or calfactant. These differences in outcome may be due to differences in phospholipid and SP-B content, amount of antioxidant phospholipids, plasmalogens, anti-inflammatory properties and viscosity among these three surfactants. Additional studies of administering surfactant non-invasively via laryngeal mask airway in preterm infants weighing >1,200 g and as an aerosol preparation are currently in progress.