CONGENITAL DIAPHRAGMATIC-HERNIA - LUNG COMPLIANCE AFTER ANTENATAL TRACHEAL OBSTRUCTION OR SURGICAL-CORRECTION OF THE DEFECT

Fetal lambs with diaphragmatic herniae (CDH) created surgically at 73 days' gestation were subjected to three different forms of intrauterin e correction: silastic patch correction of the diaphragmatic defect pl us an abdominal patch at 101 days gestation; an intrathoracic ''silo'' at 101 days; and a tracheal ''plug'' obstruction at 101 or 129 days. At 143 days' gestation (term 145-149 days), the lambs were delivered b y caesarean section and ventilated for 30 min before undergoing respir atory compliance measurements. These results were compared to those of normal lambs and animals with uncorrected herniae. The total respirat ory system compliance values in those groups undergoing corrections we re remarkably similar: those with any form of correction had a signifi cant improvement (P < 0.05) compared to those with herniae and no corr ection (patch = 1.57 = +/- 0.182 ml/cm H2O; silo = 1.53 +/- 0.179; plu g at 101 days = 1.66 +/- 0.311; plug at 129 days = 2.00 +/- 0,175; wit hout correction = 0.62 +/- 0.073). None, however, reached the values o f those with normal lungs: 2.72 +/- 0.223 (P < 0.05). This improvement in compliance in all corrected groups suggests that fetal tracheal ob struction is as effective as the two more invasive forms of open fetal surgery carried out in this study and, as this procedure lends itself to surgery through a small, uterine incision or ''minimally invasive' ' surgery, it may be the procedure of choice to reduce the incidence o f preterm labour for those human fetuses undergoing antenatal correcti on of a CDH.