A 32-week gestation male neonate born via emergency cesarean section for fetal distress develops respiratory distress at 4 hours of life. Blood gas shows pH 7.22, PaCO₂ 65 mmHg, PaO₂ 48 mmHg on 60% oxygen. Chest X-ray confirms RDS. The infant is intubated and mechanically ventilated. Which surfactant preparation is preferred as the first dose in this preterm infant with severe RDS?