During transport to the newborn nursery, the infant became dusky, developed sternal retractions, and showed 81% oxygen saturation by pulse oximetry. He was afebrile, and findings from physical examination revealed tachypnea, subcostal retractions, and decreased breath sounds present on the left. Therapy was begun with delivery of supplemental oxygen by hood at a fraction of inspired oxygen of 35%. Levels for serial C-reactive proteins and complete blood cell count were normal as were findings from blood culture. Antibiotic therapy was started on admission to the intermediate care nursery. The arterial blood gas level 2 hours after birth showed a pH of 7.22; PaO2, 60 mm Hg; and PaCO2, 58 mm Hg. A chest radiograph was obtained and repeated 6 hours later (Figure 1 and Figure 2). Within 6 hours, after management by positioning in the left lateral decubitus position and delivery of oxygen by nasal cannula, the respiratory distress, hypercarbia, and acidosis had improved. The infant was discharged following 10 days of antibiotic therapy for presumed pneumonia.