Veno-arterial extracorporeal membrane oxygenation (ECMO) brings many monitoring pitfalls due to the countercurrent blood flow, which may create left ventricular overload and perfusion imbalances between the two cerebral hemispheres. Extracorporeal cardiopulmonary resuscitation (ECPR) recipients are more susceptible to these perfusion inequities because the support starts with a completely abolished native cardiac output but is characterized by an early recovery and weaning. The median decannulation time was 26 hours (interquartile range 9–53 hours) in the INCEPTION trial [1] and 4 days (interquartile range 2–21 days) in the ARREST trial [2]. So, within hours or days, study participants experienced a transition from total support of cardiovascular and respiratory function to a complete restoration, leading to a short-lived phase of complex interplay between ECMO support and native heart and lung, favoring the genesis of unequal cerebral perfusion.