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 (ETCO2).
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 ETCO2 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 ETCO2 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 ETCO2 values increased for the first 10 min after birth, but intersubject values were heterogeneous. TVs were overall lower and ETCO2 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 ETCO2, appears to be ongoing throughout the first 10 min after birth during invasive positive pressure ventilation. Close attention to expired TV and ETCO2 levels by 10 min after birth may provide an opportunity to optimise and individualise ventilatory support for this high-risk population.
Data availability statement
Data are available on reasonable request.
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Contributors KTW and EEF conceptualized and designed the study, collected and analysed the data, drafted the initial manuscript, and reviewed and revised the manuscript. LS, KM, EK and KTVH collected data and reviewed and revised the manuscript. LM, HLH, NER, AA, MAP, HBP and JF assisted in designing the study, analysing the data, and reviewed and revised the manuscript. EEF provided oversight and serves as the guarantor for the article. All authors approved the final manuscript as submitted and agree to be accountable for all aspects of the work.
Funding Children’s Hospital of Philadelphia Delivery Room of the Future Frontier Program, Children’s Hospital of Philadelphia Pulmonary Hypoplasia Program Frontier Program, National Institute of Child Health and Human Development (K23HD084727).
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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