Pulmonary outcomes of congenital diaphragmatic hernia patients based on defect size (CDH Study Group Stage)

Background: Congenital diaphragmatic hernia (CDH) is associated with significant pulmonary morbidity. Previous investigation has shown that postnatal inpatient morbidity is linked to diaphragmatic defect size. The objective of this study was to evaluate long-term pulmonary outcomes by CDH study group defect size.Methods: A retrospective analysis was conducted for CDH patients (n=133) managed in a neonatal intensive care unit (NICU) at a single children's hospital within an adult hospital system and subsequently followed up at a comprehensive multidisciplinary CDH clinic (n=102) from January 2012 to April 2022. CDH patients were stratified according to Congenital Diaphragmatic Hernia Study Group (CDHSG) Stage, and then categorized as low-risk (LR), defect size A and B, or high-risk (HR), defect size C and D. Inpatient data, including the presence of pulmonary hypertension, extracorporeal life support (ECLS) utilization, and mechanical ventilation days, were collected. Post-discharge data including the prevalence of asthma, pulmonary hypertension, emergency department visits, the total number of hospitalizations, and average rehospitalization days were collected. Frequentist analysis was used.Results: The outcomes for 133 NICU patients were analyzed (HR: n=54, LR: n=79). During NICU stay, the prevalence of pulmonary hypertension [HR: 16/54 (30%) vs. LR: 9/79 (12%), P=0.009], ECLS utilization [HR: 19/54 (35%) vs. LR: 4/79 (5%), P<0.001], and the average number of mechanical ventilation days [HR: 17 days (IQR: 12-27) vs. LR: 5 days (IQR: 2-9), P<0.001] were significantly higher in the HR CDH group. Post NICU discharge, the prevalence of asthma [HR: 20/54 (37%), vs. LR: 17/79 (22%), P=0.050)] and the total days of rehospitalization [HR: 9 (IQR: 2-27) vs. LR: 4 (IQR: 1-8), P=0.035] were significantly higher in HR group. Of the patients seen in the comprehensive multidisciplinary CDH clinic, obstructive lung disease measured by impulse oscillometry was increased in the HR CDH population compared to the reference group [median R5Hz was 12.95 kPa/(L/s) in CDH vs. 9.8 kPa/(L/s) (P=0.010)]. Conclusions: HR CDHSG Stage is associated with worse inpatient and long-term pulmonary outcomes.