Early Repair of Congenital Diaphragmatic Hernias Requiring ECMO

Background: Congenital diaphragmatic hernia (CDH) is a severe congenital anomaly often culminating in cardiopulmonary support with extracorporeal membrane oxygenation (ECMO). Previous studies have suggested that early repair of the hernia defect while on ECMO may be associated with worse outcomes, however these studies included patients repaired off ECMO, which may select for less severe defects and poses less bleeding risk. Early CDH repair following ECMO stabilization may permit quicker normalization of pulmonary mechanics for severe CDH patients, thereby improving outcomes. We hypothesize that for patients requiring repair on ECMO, early repair, defined as within two days of ECMO cannulation, has better outcomes than when repaired late on ECMO.

Methods: A retrospective review of CDH patients who underwent hernia repair while on ECMO was examined between 2008 and 2019. Patients were divided into early (n = 24) or late repair on ECMO (n = 20). Outcomes included 30-day and overall mortality, days on ECMO, and days requiring mechanical ventilation. Analysis was performed with Fisher’s exact test for categorical variables and Mann Whitney U test for continuous variables.

Results: Prenatal imaging with MRI showed total lung volume (TLV) of 19mL for the early repair group and 24.1mL for the late repair group (p = 0.102), with percent predicted lung volumes of 13.1% versus 16.1%, respectively (p = 0.0611). The early repair group required ECMO support earlier compared to the late repair group (p = 0.0057). 30-day survival was 83.3% in the early repair group compared to 55% in the late repair group (p = 0.0528), with overall survival 50% compared to 35%, respectively (p = 0.3715).

Discussion: Despite trends of more severe disease requiring earlier stabilization on ECMO, our data suggests early repair may improve early mortality in severe CDH patients, potentially by allowing earlier compensatory lung growth while resting on ECMO.