Chest size and symmetry in congenital diaphragmatic hernia.

Infants with congenital diaphragmatic hernia have significantly increased chest circumferences. This implies that intrathoracic volumes are increased as well. Forces produced by the herniated abdominal viscera seem to provide the chief impetus for this change. Other factors may also contribute, for thoracic enlargement is asymmetric and not always ipsilateral to the hernia. The contribution of an enlarged chest to respiratory insufficiency, persistence of the fetal circulation, and hyperinflation is not fully understood, but may have relevance in evaluating new approaches to therapy.