Objective To assess the predictive value of tidal volume (Vt) of spontaneous breaths at birth in infants with congenital diaphragmatic hernia (CDH).
Design Prospective study.
Setting Tertiary neonatal intensive care unit.
Patients Thirty infants with antenatally diagnosed CDH born at Hospital Sant Joan de Déu in Barcelona from September 2013 to September 2015.
Interventions Spontaneous breaths and inflations given in the first 10 min after intubation at birth were recorded using respiratory function monitor. Only expired Vt of uninterrupted spontaneous breaths was included for analysis. Receiver operating characteristics (ROC) analysis was performed and the area under the curve (AUC) was estimated to assess the predictive accuracy of Vt.
Main outcome measures Mortality before hospital discharge and chronic lung disease (CLD) at day 28 of life.
Results There were 1.233 uninterrupted spontaneous breaths measured, and the overall mean Vt was 2.8±2.1 mL/kg. A lower Vt was found in infants who died (n=14) compared with survivors (n=16) (1.7±1.6 vs 3.7±2.1 mL/kg; p=0.008). Vt was lower in infants who died during admission or had CLD (n=20) compared with survivors without CLD (n=10) (2.0±1.7 vs 4.3±2.2 mL/kg; p=0.004). ROC analysis showed that Vt ≤2.2 mL/kg predicted mortality with 79% sensitivity and 81% specificity (AUC=0.77, p=0.013). Vt ≤3.4 mL/kg was a good predictor of death or CLD (AUC=0.80, p=0.008) with 85% sensitivity and 70% specificity.
Conclusion Vt of spontaneous breaths measured immediately after birth is associated with mortality and CLD. Vt seems to be a reliable predictor but is not an independent predictor after adjustment for observed/expected lung to head ratio and liver position.
- congenital diaphragmatic hernia
- tidal volume
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Contributors AM collected data, analysed and interpreted the data, and drafted and revised the manuscript. CCC conceived the study, drafted and revised the study protocol, collected data, and revised the manuscript. MT contributed to the conception and design of the study and revised the manuscript. JC was involved in data collection. SCP analysed and interpreted the data and revised the manuscript. ABtP conceived the study, interpreted the data, and drafted and revised the study protocol and manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Ethics approval Research ethics approval was granted for this study by the Ethics Committee of Fundació Sant Joan de Déu in Barcelona, Spain (CEIC PIC-21-13).
Provenance and peer review Not commissioned; externally peer reviewed.
Patient consent for publication Not required.
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