Extracorporeal membrane oxygenation (ECMO)
The latest RCT for ECMO (EOLIA) included 249 patients with severe ARDS, 18% with viral etiologies, and found that ECMO did not reduce mortality at day 60 [61]. Yet, a post hoc Bayesian analysis found that the interpretation of benefit versus no benefit in this trial is critically dependent upon the range of prior assumptions reflecting varying degrees of skepticism and enthusiasm of previous evidence for the benefit of ECMO—clinicians with more enthusiasm for the benefit of ECMO may be justified in considering it for certain patients [62].
Indeed, observational studies reported lower hospital mortality among patients with ARDS related to influenza A(H1N1)pdm09 with transfer to an ECMO center compared with matched non-ECMO-referred patients [63]. A case–control study also suggested survival benefit for ECMO in patients with severe MERS [64]. ECMO is likely to be associated with better outcomes when used among patients with limited organ failures and good premorbid functional status, and should be considered for patients who fail other evidence-based oxygenation strategies according to individual patient characteristics and a potential risk–benefit determination.