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

Abstract

Rationale: There is a paucity of evidence around strategies to liberate patients from veno-venous extracorporeal membrane oxygenation (V-V ECMO) for acute respiratory failure.

Objectives: 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.

Methods: 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.

Main results: 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.

Conclusion: 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.