Characteristics which were not significantly different between two groups (all p-values >0.05), under-13 and 13-or-above patients, were as follows: respiratory distress proportion 45.4%, 35.7%; mechanical ventilation support propotion 2.7%, 2.0%; median day of mechanical ventilation support 6.5 (1, 18), 17 (5, 29) days; CPAP support duration 2.4 ± 1.2, 2.1 ± 1.3 days, respectively.