Association of Standardized Liberation Trials and Duration of V-V ECMO in Patients with Acute Respiratory Failure

There is a paucity of evidence around strategies to liberate patients from veno-venous extracorporeal membrane oxygenation (V-V ECMO) for acute respiratory failure. The primary aim of this study was to determine if adopting standardized liberation trials (SLTs) for V-V ECMO is associated with duration of ECMO. The secondary aim was to identify factors associated with unsafe liberation, and the effects of unsafe liberation on mortality to ICU discharge. This was a single centre retrospective cohort study of patients on V-V ECMO for severe respiratory failure comparing endpoints between intervention (SLT) and control (no SLT) periods. A total of 262 patients were included in the study, 13% (35/262) received SLTs, and 150 patients were decannulated from ECMO. Implementing SLTs was strongly associated with the duration of V-V ECMO to first successful liberation trial (HR 1.88, 95% CI 1.16-3.06, p = 0.01) and decannulation (HR 1.92, 95% CI 1.0-3.06, p = 0.01) without increasing the frequency of unsafe liberation (SLTs - 21% [5/23]) vs. (No-SLTs - 19% [24/127]) (OR 1.19; 95% CI - 0.4-3.5, p = 0.7). Unsafe liberation was strongly associated with ICU mortality (HR 4.15, 95% CI 1.24-13.9, p = 0.02). Factors associated with unsafe liberation were respiratory rate (OR 1.49 per 5 breaths/min increase, 95% CI 1.07-2.08, p =0.02) and PaO2/FiO2 (OR 0.73 per 30 mmHg increase, 95% CI 0.57-0.93, p = 0.01) immediately prior to decannulation. Incorporating SLTs was significantly associated with duration of V-V ECMO without increasing the frequency of unsafe liberation. Unsafe liberation was associated with increased ICU mortality.