Respiratory function after birth in infants with congenital diaphragmatic hernia.

Objective: To characterise the transitional pulmonary physiology of infants with congenital diaphragmatic hernia (CDH) using measures of expiratory tidal volume (TV) and end-tidal carbon dioxide (ETCO).

Design: Prospective single-centre observational study.

Setting: Quaternary neonatal intensive care unit.

Patients: Infants with an antenatal diagnosis of CDH born at the Children's Hospital of Philadelphia.

Interventions: TV and ETCO were simultaneously recorded using a respiratory function monitor (RFM) during invasive positive pressure ventilation immediately after birth.

Main Outcome Measures: TV per birth weight and ETCO values were summarised for each minute after birth. Subgroups of interest were defined by liver position (thoracic vs abdominal) and extracorporeal membrane oxygenation (ECMO) treatment.

Results: RFM data were available for 50 infants from intubation until a median (IQR) of 9 (7-14) min after birth. TV and ETCO values increased for the first 10 min after birth, but intersubject values were heterogeneous. TVs were overall lower and ETCO values higher in infants with an intrathoracic liver and infants who were ultimately treated with ECMO. On hospital discharge, survival was 88% (n=43) and 34% (n=17) of infants were treated with ECMO.

Conclusion: Respiratory function immediately after birth is heterogeneous for infants with CDH. Lung aeration, as evidenced by expired TV and ETCO, appears to be ongoing throughout the first 10 min after birth during invasive positive pressure ventilation. Close attention to expired TV and ETCO levels by 10 min after birth may provide an opportunity to optimise and individualise ventilatory support for this high-risk population.