Background/purpose: The benefit of extracorporeal membrane oxygenation (ECMO) in improving survival of neonates with congenital diaphragmatic hernia (CDH) has never been clearly demonstrated. This may be due to comparisons made between treatment groups of unequal illness severity and the low statistical power of analyses from previous studies. The authors analyzed the data from the multicenter CDH registry to determine if ECMO improves survival in CDH neonates with a high risk of mortality.
Methods: A total of 730 neonates were enrolled in the CDH Registry from January 1995 to November 1997. Of these, 632 neonates had a complete data set and were eligible for ECMO by the weight criterion of greater than 2.0 kg. Multivariate logistic regression analysis was used to assess mortality risk for each neonate based on previously validated independent predictors of survival: birth weight and 5-minute Apgar. Five quintile groups were defined based on increasing predictive mortality risk. Multivariate logistic regression and chi2 analyses with birth weight, Apgar score at 5 minutes, and predictive mortality risk as covariates were then performed to assess survival benefit of ECMO compared with conventional therapy alone. Patient survival rate was defined as survival to discharge from hospital.
Results: When analyzing all 632 neonates, ECMO neonates (n = 289) had a decidedly lower survival rate (52.9% v 77.3%, P< .001) than non-ECMO neonates (n = 343) without standardizing for the degree of illness. However, when taking into account the patients' predictive mortality risk, ECMO was associated with improved survival in the neonates with mortality risk < or = 80% (P < .05). Furthermore, ECMO was shown to be a positive independent predictor of survival when accounting for the covariates of birth weight, 5-minute Apgar, and mortality risk (P < .05).
Conclusions: ECMO significantly improves survival rates for those CDH neonates with a predictive mortality risk > or = 80%. Generally, the more critically ill the patient with CDH, the more marked the survival benefit obtained.