We undertook a multi-hospital collective study to evaluate outcomes of neonatal respiratory distress syndrome (RDS) patients treated with pulmonary surfactant (PS) over 17 yr in Korea (Group I; 1990/91, Group II; 1996, Group III; 2002, and Group IV; 2007). There were 60 neonates in Group I (16 hospitals), 1,179 in Group II (64), 1,595 in Group III (62), and 1,921 in Group IV (57). We adopted Bo...