(208) Oxygen Challenge Test in Neonates on VA ECMO

Introduction: In neonates on venoarterial (VA) extracorporeal membrane oxygenation (ECMO), the response to the oxygen challenge test (OCT) depends on the recovery of the lungs' oxygenation function, ECMO flow, and native cardiac output. While on venovenous (VV) ECMO, the OCT primarily relies on the recovery of lung oxygenation function. In this study, we aimed to examine the response to OCT in neonates on VA ECMO close to decannulation.

Methods: Following IRB approval, we analyzed demographic, clinical, and outcome data. The delta P/F ratio was calculated using the change in PaO2 and FiO2 with OCT. The chi-square and Mann-Whitney U tests were used to compare the two groups: survivors and deceased.

Results: The median (IQR) age (days), P/F, and A-a gradient at cannulation were 2 (1-4), 37 (31-45), and 611 (590-624), respectively, in a total of 63 neonates. The duration of ECMO and mortality were 146 (91-242) hours and 20.6%, respectively. Demographic and oxygenation indices at the time of cannulation were similar in both groups. OCT was performed 1 (0-2) days before trial-off at an ECMO flow of 59 (43-78) ml/kg/min. Delta P/F with OCT was 291 (191-376) and was similar in both groups. However, oxygenation indices at the time of decannulation were significantly worse in the deceased group.

Conclusions: In neonates on VA ECMO, OCT shows promise in assessing readiness for decannulation. However, the response to OCT is not predictive of mortality.