In preterm infants with respiratory distress syndrome, mechanical ventilation is related to increased risk of death and complications. Surfactant is an important methods to reduce mortality and intubation rates. INSURE technique is a standard method to administrate surfactant. However, several preterm infants need two or more surfactant, and therefore one more intubation is needed. How to reduce the times of intubation is an challenges for neonatologists.

INSURE technique meas surfactant administration through intubation-surfactant-extubation. And noninvasive ventilation is immediately used after surfactant.

The differences of modified INSURE compared with INSURE is intubation-surfactant-X-ray relieved-extubation. Extubation and noninvasive ventilation is used after the X-ray relieving.

Inclusion Criteria:

• All preterm infants with respiratory distress syndrome

Exclusion Criteria:

• congenital abnormalities or refuse the trials