The recommendations of the guidelines on “prone positioning“ and “ECMO“ must be contested (1). The evidence in support of prone positioning as the primary treatment option in patients with severe ARDS is derived from a meta-analysis (2) which showed a survival benefit in a subgroup analysis. The authors’ conclusion, “…no convincing evidence for benefit or harm of prone positioning…“.
The EOLIA study (early versus rescue use of ECMO ) cited in the guideline as proof of the “rescue character“ of ECMO, was terminated after 75% of the calculated sample size because no mortality difference was found in the intention-to-treat analysis. A secondary analysis presented by the authors themselves showed a different result: “crossover to ECMO or death in patients in the control group versus death in the ECMO group“ yielded an absolute mortality difference of 23% in favor of the ECMO group (p<0.001). At the time of study termination, 28% of patients in the prone-positioning group with persistent severe hypoxia had switched to the ECMO treatment group. These control group patients who received “late” ECMO treatment had a 60-day mortality of 57% compared to 35% in the group of patients with primary ECMO treatment.
The statement—which is repeated several times in the guideline—that in patients with severe ARDS no difference exists between early ECMO treatment and conventional therapy (prone positioning, relaxation, etc.) is not supported by the available data. Similarly, the EOLIA study does not provide evidence to support the recommendation to use ECMO as a “rescue option“ only after all conventional treatment modalities have been exhausted in patients with ARDS. Unfortunately, as the result of these guideline recommendations, valuable time will be wasted in patients with severe ARDS on treatments which should only be used to bridge the time spent waiting for the ECMO team, if at all.
Dr. med. Michael Schütz
Prof. Dr. med. Hans-Bernd Hopf
Abteilung für Anästhesie und Perioperative Medizin
Asklepios Klinik Langen
|1.||Fichtner F, Moerer O, Laudi S, Weber-Carstens S, Nothacker M, Kaisers U: Clinical practice guideline: Mechanical ventilation and extracorporeal membrane oxygenation in acute respiratory insufficiency. Dtsch Arztebl Int 2018; 115: 840–7 VOLLTEXT|
|2.||Bloomfield R, Noble DW, Sudlow A: Prone position for acute respiratory failure in adults. Cochrane Database Sys Rev 2015; 11: CD00809 CrossRef|
|3.||Combes A, Hajage D, Capellier G, et al.: Extracorporeal membrane oxygenation for severe acute respiratory distress syndrome. N Engl J Med 2018; 378: 1965–75 CrossRef MEDLINE|