Association Between Mortality and Ventilator Parameters in Children With Respiratory Failure on ECMO

BACKGROUND: In refractory respiratory failure, extracorporeal membrane oxygenation (ECMO) is a rescue therapy to prevent ventilator-induced lung injury. Optimal ventilator parameters during ECMO remain unknown. Our objective was to describe the association between mortality and ventilator parameters during ECMO for neonatal and pediatric respiratory failure.

METHODS: We performed a secondary analysis of the Bleeding and Thrombosis on ECMO dataset. Ventilator parameters included breathing frequency, tidal volume, peak inspiratory pressure, PEEP, dynamic driving pressure, pressure support, mean airway pressure, and F_IO2. Parameters were evaluated before cannulation, on the calendar day of ECMO initiation (ECMO day 1), and the day before ECMO separation.

RESULTS: Of 237 included subjects analyzed, 64% were neonates, of whom 36% had a congenital diaphragmatic hernia. Of all the subjects, 67% were supported on venoarterial ECMO. Overall in-hospital mortality was 35% (n = 83). The median (interquartile range) PEEP on ECMO day 1 was 8 (5.0–10.0) cm H₂O for neonates and 10 (8.0–10.0) cm H₂O for pediatric subjects. By multivariable analysis, higher PEEP on ECMO day 1 in neonates was associated with lower odds of in-hospital mortality (odds ratio 0.77, 95% CI 0.62–0.92; P = .01), with a further amplified effect in neonates with congenital diaphragmatic hernia (odds ratio 0.59, 95% CI 0.41–0.86; P = .005). No ventilator type or parameter was associated with mortality in pediatric subjects.

CONCLUSIONS: Avoiding low PEEP on ECMO day 1 for neonates on ECMO may be beneficial, particularly those with a congenital diaphragmatic hernia. No additional ventilator parameters were associated with mortality in either neonatal or pediatric subjects. PEEP is a modifiable parameter that may improve neonatal survival during ECMO and requires further investigation.