Prediction of survival in infants with congenital diaphragmatic hernia and the response to inhaled nitric oxide

The use of inhaled nitric oxide (iNO) in treating pulmonary hypertension in infants with congenital diaphragmatic hernia (CDH) is controversial. Our aims were to identify factors associated with survival in CDH infants and whether this was influenced by the response to iNO. Results of CDH infants treated in a tertiary surgical and medical perinatal centre in a ten year period (2011–2021) were reviewed. Factors affecting survival were determined. To assess the response to iNO, blood gases prior to and 30 to 60 min after initiation of iNO were analysed and PaO(2)/FiO(2) ratios and oxygenation indices (OI) calculated. One hundred and five infants were admitted with CDH; 46 (43.8%) infants died. The CDH infants who died had a lower median observed to expected lung to head ratio (O/E LHR) (p < 0.001) and a higher median highest OI on day 1 (HOId1) (p < 0.001). HOId1 predicted survival after adjusting for gestational age, Apgar score at 5 min and O/E LHR (odds ratio 0.948 (95% confidence intervals 0.913–0.983)). Seventy-two infants (68.6%) received iNO; 28 survived to discharge. The median PaO(2) (46.7 versus 58.8 mmHg, p < 0.001) and the median PaO(2)/FiO(2) ratio (49.4 versus 58.8, p = 0.003) improved post iNO initiation. The percentage change in the PaO(2)/FiO(2) ratio post iNO initiation was higher in infants who survived (69.4%) compared to infants who died (10.2%), p = 0.018. Conclusion: The highest OI on day 1 predicted survival. iNO improved oxygenation in certain CDH infants and a positive response was more likely in those who survived.