Mortality among infants with high-risk congenital diaphragmatic hernia in Singapore

Several factors suggested to predict mortality in congenital diaphragmatic hernia (CDH) have not always been applicable in different centers. A retrospective review was conducted of 19 consecutive neonates in Singapore in whom CDH was diagnosed within 12 hours of birth to identify factors associated with mortality. Of the 19 cases, 15 (79%) were diagnosed using antenatal ultrasonography. Eight (42%) underwent primary repair at a median age of 23 hours (range, 12 to 50 hours). Of the 19 infants, 15 died (mortality rate, 79%). Survivors until hospital discharge were compared with nonsurvivors. Antenatal diagnosis and stomach position in left-sided defects had no effect on outcome, although polyhydramnios tended to be associated with nonsurvival. Significant postnatal factors associated with mortality included a low arterial pH level, low initial arterial-alveolar oxygen ratio, high initial alveolar-arterial oxygen gradient, as well as high oxygenation and ventilation indices. These results reflect difficulty in oxygenation because of pulmonary hypoplasia despite evidence of adequate ventilation. There was no difference between survivors and nonsurvivors in either their initial or best postductal blood gases. The "Bohn quadrants" did not aid in predicting survival of infants who underwent repair because all eight such infants had best postductal carbon dioxide values of less than 40 mm Hg and ventilation indices of less than 1,000. Yet only four (50%) survived until hospital discharge. Large-scale evaluation of these factors may be required in the future to demonstrate their validity and reliability because of changing management strategies for CDH.