Fig. 1

Flow-chart of the study protocol. Legend: Between November 2007 and March 2014, 74 patients underwent lung transplantation, and 9 of these were excluded from the study because of urgent surgery or retransplant. Out of the remaining 65 patients, 38 presented “intermediate” intraoperative severity: 23 patients in the 2007–2010 who “received standard intraoperative treatment,” 15 patients in the 2011–2014 who received “standard intraoperative treatment + extracorporeal carbon dioxide removal (ECCO₂R). “Intermediate” intraoperative severity: patients who developed intraoperative severe respiratory acidosis with maintained oxygenation function (i.e., pH <7.25, paCO₂ >60mmHg PaO₂/FiO₂ >150), not associated with hemodynamic instability