This is a multi-center, blinded, randomized controlled clinical trial to evaluate the effects of booster doses of exogenous surfactant (Infasurf®, calfactant) in addition to inhaled nitric oxide (iNO) on the outcome of survival without bronchopulmonary dysplasia (BPD, or chronic lung disease of prematurity, characterized by chronic lung dysfunction) at 36 weeks' post-menstrual age (PMA) in extremely low gestational age (ELGAN) infants that are at high risk of the development of BPD. This multi-center trial, with a planned enrollment of 524 infants, will also enable us to evaluate for any adverse effects of late surfactant treatment on short- and long-term outcomes, as we will be collecting data on effects of dosing of late surfactant, co-morbidities of prematurity and neurodevelopmental and pulmonary outcome at 1 year and 24 months corrected age. In addition, we will collect biological specimens for evaluation of the effects of late surfactant replacement therapy (administered as described in this trial) on surfactant function and inflammatory markers.