Prospective analysis of lung-to-head ratio predicts survival for patients with prenatally diagnosed congenital diaphragmatic hernia

Abstract

Background: Accurate prenatal prediction of outcome for fetuses who have congenital diaphragmatic hernia (CDH) is very difficult. The authors previously reported a retrospective analysis of risk factors for fetal CDH and proposed a new index of severity: the lung-to-head ratio (LHR). The authors now report a prospective study to test whether this new index predicts neonatal outcome. Methods: Fifteen patients who had left-sided CDH were sonographically evaluated at the University of California, San Francisco (UCSF) and followed prenatally and postnatally. LHR was measured at 24 to 26 weeks' gestation. Outcome variables included survival and the need for extracorporeal membrane oxygenation (ECMO). Results: Overall survival was 47%. LHR ranged from 0.62 to 1.86. No patient with an LHR of less than 1.0 (n = 3) survived despite ECMO, whereas all patients with an LHR greater than 1.4 survived (n = 4), one requiring ECMO. LHR values between 1.0 to 1.4 were associated with 38% survival (n = 8), 75% requiring ECMO. Overall, survivors had a mean LHR of 1.4 ± 0.33 and nonsurvivors, 1.05 ± 0.3 ( P < .05). Conclusion: The LHR is a useful index to help predict neonatal outcome in patients who have left-sided CDH.