Observed/Expected Lung-To-Head Ratio and Total Lung Volumes That Identify Fetuses With Severe Congenital Diaphragmatic Hernia in a North American Fetal Center.

Objective: To define the ultrasound observed/expected lung-to-head ratio (O/E LHR) and magnetic resonance imaging (MRI) observed/expected total lung volume (O/E TLV) cut-offs associated with survival and lack of extracorporeal membrane oxygenation (ECMO) utilization to determine the most severe cohort that may benefit from fetal intervention.

Methods: Retrospective review of patients with a prenatal diagnosis of isolated left or right congenital diaphragmatic hernia (L CDH, R CDH) seen and delivered at our level III fetal center from January 2013-July 2023. Data were extracted from our clinical outcome database. Characteristics of survivors and non-survivors were compared for both the L CDH and R CDH groups. For both O/E LHR and O/E TLV, the Youden criteria were then used to determine a good sensitivity and specificity for predicting survival and ECMO utilization for L and R CDH, respectively, in Receiver Operator Characteristic (ROC) curve analysis.

Results: 340 patients were included in the study, including 283 (83.2%) with L CDH and 57 (16.8%) with R CDH. The median [interquartile range, IQR] O/E LHR for L and R CDH was 37.9 [28.7-47.3] and 49.0 [40.0-64.5], respectively. The median O/E TLV for L and R CDH was 36.0 [28.0-48.0] and 25.3 [23.6-29.8], respectively. For survival, an O/E LHR of 28.1% and O/E TLV of 34.0% and an O/E LHR of 46.8% and O/E TLV of 17.6% were the best cut-offs for L and R CDH, respectively. For ECMO utilization, an O/E LHR of 32.8% and O/E TLV of 35.3% and an O/E LHR of 47.0% and O/E TLV of 22.0% were the best cut-offs for L and R CDH, respectively.

Conclusion: We report the best ultrasound O/E LHR and MRI TLV cut-offs associated with survival and lack of ECMO utilization in our cohort.