A 4-month-old boy is brought to the pediatrician for a follow-up examination. He was born at 26 weeks’ gestation and spent 2 months in ICU receiving oxygen and nutritional support. He is now on home oxygen. He is at the 5th percentile for length and weight. ECG shows right-axis deviation. A loud P2 is heard on chest auscultation. Which of the following is the most likely explanation for this patient’s findings?
Acrocyanosis
Bronchopulmonary dysplasia
Hyaline membrane disease
Immature lower esophageal sphincter
Transient tachypnea of the newborn
