Congenital Diaphragmatic Hernia (CDH)

Congenital diaphragmatic hernia is a developmental defect in which abdominal viscera pass through an opening in the diaphragm into the thorax. The displaced organs cause a mass effect on the developing lungs, which results in pulmonary hypoplasia and pulmonary hypertension. Most defects, over 85%, are on the left. Pulmonary hypertension in CDH arises from abnormal development of the pulmonary vessels: increased arterial remodeling, a reduced density of the vascular bed and altered vascular responsiveness. The heart is affected as well. Cardiac dysfunction in CDH is bilateral, with an overworked right ventricle and an underdeveloped left ventricle. Neonatal care therefore addresses three overlapping problems: pulmonary hypoplasia, pulmonary hypertension and cardiac dysfunction. Pulmonary hypoplasia, together with early pulmonary hypertension and cardiac dysfunction, drives early mortality. Pulmonary vascular pressures are high in every newborn at birth and remain high until the lungs are appropriately ventilated, and in CDH this transition is slower than normal. The clinical picture can evolve over time, so a newborn who looks stable at first can deteriorate. For these reasons, treatment first protects the fragile lungs and supports the...