Liberation From Venovenous Extracorporeal Membrane Oxygenation for Respiratory Failure: A Scoping Review

Association of Standardized Liberation Trials and Duration of Venovenous Extracorporeal Membrane Oxygenation in Patients with Acute Respiratory Failure

Rationale: There is a paucity of evidence around strategies to liberate patients from venovenous (VV) extracorporeal membrane oxygenation (ECMO) for acute respiratory failure. Objectives: The primary aim of this study was to determine if adopting standardized liberation trials (SLTs) for VV ECMO is associated with the duration of ECMO. The secondary aim was to identify factors associated with unsafe liberation and the effects of unsafe liberation on mortality to intensive care unit (ICU) discharge. Methods: This was a single-center retrospective cohort study of patients on VV ECMO for severe respiratory failure comparing endpoints between intervention (SLT) and control (no SLT) periods. Results: A total of 262 patients were included in the study, 13% (35 of 262) received SLTs, and 150 patients were decannulated from ECMO. Implementing SLTs was strongly associated with the duration of VV ECMO to first successful liberation trial (hazard ratio [HR], 1.88 [95% confidence interval (CI), 1.16 to 3.06]; P = 0.01) and decannulation (HR, 1.92 [95% CI, 1.0 to 3.06]; P = 0.01) without increasing the frequency of unsafe liberation (21% [5 of 23] with SLTs vs. 19% [24 of 127] without SLTs; odds ratio [OR], 1.19 [95% CI, -0.4 to 3.5]; P = 0.7). Unsafe liberation was strongly associated with ICU mortality (HR, 4.15 [95% CI, 1.24 to 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 to 2.08]; P = 0.02) and ratio of partial pressure of arterial oxygen to fraction of inspired oxygen (OR, 0.73 per 30 mm Hg increase [95% CI, 0.57 to 0.93]; P = 0.01) immediately before decannulation. Conclusions: Incorporating SLTs was significantly associated with the duration of VV ECMO, without increasing the frequency of unsafe liberation. Unsafe liberation was associated with increased ICU mortality.

Mechanical ventilation settings during weaning from venovenous extracorporeal membrane oxygenation

BACKGROUND

The optimal timing of weaning from venovenous extracorporeal membrane oxygenation (VV ECMO) and its modalities have been rarely studied.

METHODS

Retrospective, multicenter cohort study over 7 years in two tertiary ICUs, high-volume ECMO centers in France and Italy. Patients with ARDS on ECMO and successfully weaned from VV ECMO were classified based on their mechanical ventilation modality during the sweep gas-off trial (SGOT) with either controlled mechanical ventilation or spontaneous breathing (i.e. pressure support ventilation). The primary endpoint was the time to successful weaning from mechanical ventilation within 90 days post-ECMO weaning.

RESULTS

292 adult patients with severe ARDS were weaned from controlled ventilation, and 101 were on spontaneous breathing during SGOT. The 90-day probability of successful weaning from mechanical ventilation was not significantly different between the two groups (sHR [95% CI], 1.23 [0.84-1.82]). ECMO-related complications were not statistically different between patients receiving these two mechanical ventilation strategies. After adjusting for covariates, older age, higher pre-ECMO sequential organ failure assessment score, pneumothorax, ventilator-associated pneumonia, and renal replacement therapy, but not mechanical ventilation modalities during SGOT, were independently associated with a lower probability of successful weaning from mechanical ventilation after ECMO weaning.

CONCLUSIONS

Time to successful weaning from mechanical ventilation within 90 days post-ECMO was not associated with the mechanical ventilation strategy used during SGOT. Further research is needed to assess the optimal ventilation strategy during weaning off VV ECMO and its impact on short- and long-term outcomes.