A 3-year retrospective study of 173 neonates treated with extracorporeal membrane oxygenation in the United Kingdom identified 9 cases of irreversible lung dysplasia, including alveolar capillary dysplasia (n = 5), surfactant protein B deficiency (n = 1), pulmonary hypoplasia (n = 1), pulmonary lymphangiectasis (n = 1), and combined lymphangiectasis and hypoplasia (n = 1).