Determination of brain death/death by neurologic criteria (BD/DNC) in patients supported with extracorporeal membrane oxygenation (ECMO) is particularly challenging due to extracorporeal carbon dioxide clearance, which may interfere with apnea testing. The 2023 unified consensus guideline introduced stricter physiologic requirements, including a mandatory arterial pH threshold during apnea testing.

We report a pediatric patient supported with venoarterial ECMO following cardiac arrest in whom BD/DNC was diagnosed in 2021 according to the 2011 pediatric guideline. Apnea testing was performed using controlled reduction of sweep gas flow with serial arterial blood gas monitoring. The 2023 consensus criteria were retrospectively applied to the original clinical data.

During apnea testing, arterial carbon dioxide tension increased from 43.1 to 74.5 mm Hg without spontaneous respiratory effort. Arterial pH decreased to 7.19, fulfilling the acidemia requirement introduced in the 2023 guideline. Clinical examination met all prerequisites under both frameworks. The diagnosis established under the 2011 guideline remained fully concordant with the updated 2023 criteria.

This case suggests that ECMO-adapted apnea testing may be a feasible approach for BD/DNC determination under the 2023 consensus framework when physiologic conditions are carefully optimized.