Inhaled nitric oxide in preterm babies with respiratory failure or ventilator dependence will:

1. decrease the incidence of Bronchopulmonary Dysplasia (BPD) or death
2. shorten the length of oxygen therapy and hospital stay ,reduce the cost of hospital stay without increasing adverse effect

Bronchopulmonary dysplasia remains a problem in neonatal intensive care unit (NICU) all over the world. This multicenter, non-randomized, unmasked clinical trial evaluate the efficacy of inhaled nitric oxide (iNO) in the treatment of the preterm infant with developing bronchopulmonary dysplasia.

Infants were followed until death or discharge to home. The trial will compare iNO therapy to conventional management strategies (including treatment with nasal continuous positive airway pressure (CPAP), surfactant and high frequency ventilation as adjuncts to iNO therapy) as the control.

During the initial dosing, iNO was started at 5 ppm and could be decreased to 1-2 ppm. The Infants would inhale NO until weaned. Infants will be monitored for signs of toxicity due to cumulated dosage of NO and its metabolites, such as methemoglobin, and nitrite and nitrate in blood and urine, and nitrogen dioxide in ventilator circuit to the patient.

Inclusion Criteria:

• GA<=34w,less than 7 days of age,oxygenation index (OI) of more than 10 after being ventilated for more than 48 hours or surfactant therapy
• GA<=34w,between 7 to 30 days of age, requiring assisted ventilator or nasal continuous positive airway pressure for more than 2 days

Exclusion Criteria:

• lethal congenital anomalies or congenital heart disease (including an atrial septal defect larger than 1 cm and a ventricular septal defect larger than 2 mm)
• active pulmonary hemorrhage, unevaluated pneumothorax
• preexisting bilateral grade 3-4 intraventricular hemorrhage
• a platelet count <100*10^9/l
• an expected duration of ventilation of less than 48 hours