A boy was born at 32 weeks of gestation. 2 hours after the birth he developed respiratory distress (RD). The RD severity assessed by Silverman score was 5. The respiratory disorders progressed, respiratory failure could not be eliminated by Martin-Bouyer CPAP (continuous positive airway pressure). X-ray of lungs shows reticular and nodular pattern, air bronchogram. What is the most likely cause of respiratory distress syndrome?