Purpose Congenital diaphragmatic hernia (CDH) affects approximately 1 in 4,000 births. Mortality of these infants remains high, ranging from 20 to 40%. Predicting outcomes of these infants has been problematic and complex. The availability of an easy and accurate method to predict outcomes in CDH infants post-delivery would be extremely useful in their management. The purpose of this study was to assess the ability of a simple formula, based on blood gas values obtained in the first 24 hours of life, to accurately predict mortality in CDH newborns.
Methods A retrospective chart review was performed. The study population was obtained from 2 San Antonio hospitals (Wilford Hall Medical Center and Santa Rosa Children's Hospital). All liveborn infants from January 1996 to August 2004 with the diagnosis of CDH were included, including those with associated anomalies. The prediction formula (PF) used was the highest PaO2 minus the highest PaCO2 measured in the first 24 hours of life, regardless of ventilation technique, but prior to ECMO if needed. Data were analyzed with SigmaStat® statistical program.
Summary of Results 85 medical charts of infants with CDH were reviewed. Overall survival rate was 61%. The average birth weight was 2731 ± 84 g and 24% were less than 37 weeks gestation. Premature and low birth weight (< 2500 g) infants had lower survival (p < .01). Gender and prenatal diagnosis were not predictive of outcome. Those CDH infants with associated anomalies had an overall survival rate of 41% versus 75% without anomalies. ECMO was used in 27% of patients, with an average of 9 ± 4 ECMO days. A positive PF predicted survival 96% of the time (positive predictive value 0.89, sensitivity 0.96, specificity 0.85, p < .001).
Conclusion This simple method appears to be a promising tool for predicting survival in newborns with CDH. Its utility needs to be further evaluated in a larger population of patients.