Classification according to blood pH
Arterial blood gases (ABG) were drawn at cannulation in the vast majority of cases. Then, ABG were performed regularly during the follow-up. We classified patients into 3 groups depending on the first arterial pH level at cannulation of VA ECMO: pH<7 (Group 1), pH between 7 and 7.2 (Group 2) and pH>7.2 (Group 3). We chose these cut-off points according to articles published in literature(4,6) and with consultation of the authors.