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

Abstract

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 PaO2/FiO2 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 PaO2 (46.7 versus 58.8 mmHg, p < 0.001) and the median PaO2/FiO2 ratio (49.4 versus 58.8, p = 0.003) improved post iNO initiation. The percentage change in the PaO2/FiO2 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. What is Known:• The use of iNO is controversial in infants with CDH with respect to whether it improves survival. What is New:• We have examined predictors of survival in CDH infants including the response to iNO and demonstrated that the highest oxygenation index on day 1 predicted survival (AUCROC =0.908).• Certain infants with CDH responded to iNO and those with a greater response were more likely to survive.

Dynamics of pulmonary hypertension severity in the first 48 h in neonates with prenatally diagnosed congenital diaphragmatic hernia

“…The usage of iNO is widely variable among institutions and an ongoing topic of discussion. Studies thus far have failed to show a reduction in mortality rate using iNO, but have shown a short-term benefit in oxygenation among some CDH infants ( 31 , 32 ). Recent studies even suggest a higher mortality in infants treated with iNO ( 33 ), although these patients were also the sickest who were most likely to receive all therapies available, and have a fatal outcome nonetheless.…”

Management of infants with congenital diaphragmatic hernia and pulmonary hypertension—one size does not fit all

“…In one, 38 of 95 infants treated with iNO had a positive response in oxygenation and were less likely to require ECLS, 5 and in another, 28 of 72 infants with a positive response were more likely to survive. 6 The likely reason for this differential effect is that the PH seen in CDH infants is complex and iNO only addresses certain components. Neonates with CDH and PH have pulmonary vasoconstriction and ventilation-perfusion mismatching, which should respond to iNO.…”