Malformations associated with congenital diaphragmatic hernia: Impact on survival

Congenital diaphragmatic hernia (CDH) is associated with high mortality. Survival is influenced by the extent of pulmonary hypoplasia and additional congenital defects. The purpose of this study was to assess the association of congenital anomalies and admission capillary carbon dioxide levels (PcCO2), as a measure of extent of pulmonary hypoplasia, on survival in neonates with CDH.

This is a retrospective review of neonates with CDH admitted to a tertiary neonatal intensive care unit between 1990 and 2014. Logistic regression was used to assess whether hospital survival was associated with admission PcCO2 or associated anomalies (isolated CDH, CDH with cardiovascular anomalies, and CDH with noncardiac anomalies). The probabilities of survival (POS) score, based on birth weight and 5-min Apgar as defined by the Congenital Diaphragmatic Hernia Study Group were included as a covariate.

Of 97 patients, 55 had additional malformations (cardiovascular n=12, noncardiac anomalies n=43). POS was lower in CDH with other anomalies compared to isolated CDH. Survival rate was 61.9%, 53.5% and 41.7% in isolated CDH, CDH with noncardiac anomalies and CDH with cardiovascular anomalies, respectively. After adjusting for POS score the likelihood of survival in CDH groups with additional anomalies was similar to isolated CDH (OR 0.95, 95% CI 0.22-4.15, and 1.10, 0.39-3.08, for CDH with and without cardiovascular anomalies, respectively). After adjusting for POS score, lower PcCO2 levels (OR=1.25 per 5mmHg decrease, P=0.003) were associated with better survival.

Neonates with CDH have a high prevalence of congenital malformations. However, after adjusting for POS score the presence of additional anomalies was not associated with survival. The POS score and admission PcCO2 were important prognosticating factors for survival.