Correction of congenital diaphragmatic hernia in utero. II. Simulated correction permits fetal lung growth with survival at birth.

Infants with congenital diaphragmatic hernia (CDH) die because their lungs are hypoplastic. If hypoplasia is a developmental consequence of compression by herniated viscera, decompression before birth may allow pulmonary development and survival at term. A conical silicone rubber balloon progressively inflated (60 to 150 ml) in the left hemithoraxi of fetal limbs (days 100 to 145) simulated compression by growing viscera ("CDH"). Six of six neonates delivered by cesarean section died of severe respiratory insufficiency, despite maximal resuscitation. Lungs were hypoplastic. Lung weight and air capacity were significantly reduced (P less than 0.01) as compared with controls. Pressure-volume curves revealed decreased compliance and barium gelatin injections revealed decreased cross-sectional area of the pulmonary vascular bed. Deflation of the balloon at day 120 (simulated "correction") allowed sufficient lung growth and development to alleviate respiratory insufficiency and to assure survival in five of five lambs delivered by cesarean section. Simulated correction produced a significant (P less than 0.01) increase in lung weight, air capacity, compliance, and area of the pulmonary vascular bed. Efficacy of in utero correction was confirmed by three twin studies in which simulated CDH in one twin was compared with simulated correction in the other. Infants with CDH may be salvaged by in utero correction.