Objective To determine whether the respiratory response to resuscitation in infants with congenital diaphragmatic hernia (CDH) as measured by a respiratory function monitor differed between those who did and did not survive.

Design Observational study.

Setting Tertiary perinatal centre.

Patients Thirty-eight infants born at 34 weeks of gestation or greater and diagnosed antenatally with a CDH.

Interventions Expiratory tidal volume (VTe), peak inflation pressure (PIP) and end-tidal carbon dioxide level (ETCO₂) were simultaneously recorded during resuscitation using a respiratory function monitor. Oxygen saturation was also monitored.

Main outcome measures Mortality related to the median VTe, PIP, compliance (VTe divided by PIP) and ETCO₂ levels in the first and last minute of recorded resuscitation and the maximum oxygen saturation.

Results The median gestational age, birth weight and duration of resuscitation of the 11 infants who died did not differ significantly from those who survived. During the first minute of recorded resuscitation, the VTe (median 1.89 vs 2.68 mL/kg) (p=0.009)), the ETCO₂ (median 11.7 vs 41.7 mm Hg) (p=0.023)) and the compliance (0.06 vs 0.08 mL/cm H₂O/kg) (p=0.018)) were lower in the non-survivors. In the last minute, the PIP was higher (32.5 vs 30.3 cm H₂O) (p=0.03)), the VTe (3.22 vs 4.66 mL/kg) (p=0.003)) and compliance (0.10 vs 0.15 mL/cm H₂O/kg) (p=0.004)) were lower in the non-survivors. The maximum oxygen saturation achieved in the labour suite was lower in the non-survivors (93% vs 100%) (p=0.037).

Conclusions Infants with CDH who did not survive responded less well even to initial resuscitation.