To the Editor We read with great interest the Research Letter by Mustafa et al.1 The authors interpret their findings as demonstrating “promising outcomes” and as suggesting safety and effectiveness of venovenous extracorporeal membrane oxygenation (ECMO) in patients with coronavirus disease 2019 (COVID-19). However, several clarifications are required before valid conclusions are possible.
Eleven patients (28%) who were still in the intensive care unit (8 [20%] still receiving ECMO) were not included in the final data analysis. Thus, the validity of the outcome data is questionable. For example, the reported mortality of 15% is unusually low. In a recent report of 83 patients receiving ECMO for severe COVID-19–associated acute respiratory distress syndrome in a high-volume ECMO center experienced in the care of severe acute respiratory distress syndrome, 30 patients (36%) died at 60 days.2 Obviously, the 11 patients still in the intensive care unit at the time of data analysis need to be included in the final analysis, especially because survival was the primary end point. After all, if all of them should have subsequently died, the mortality would be 42.5%. In any case, a possible explanation for the considerable discrepancy in mortality between this and other reports would be welcomed.
The authors state that complications had been minimal. Besides the fact that minimal is not quantified, leaving the true incidence of complications unknown, the reported low incidence of complications in this population is remarkable. By contrast, of the 83 patients studied by Schmidt et al,2 4 patients (5%) and 11 patients (13%) developed hemorrhagic stroke and intravascular hemolysis, respectively, and 64 (77%) and 38 (46%) required transfusion of packed red blood cells and kidney replacement therapy, respectively. Because anticoagulation is an important treatment component of severe COVID-19,3,4 details regarding the anticoagulation management would be very helpful.
The authors report a mean time of 13 days from ECMO initiation to extubation. However, Figure, B in their article1 suggests that 5 of 40 patients (12.5%) had not been extubated by the end of the observation period. This would imply that the reported mean time underestimates the ultimate intubation times. Thus, information regarding the final intubation times would be important.
In summary, while the reported outcomes seem promising, additional information is required before the findings can be placed in proper clinical perspective. Although the application of ECMO in COVID-19–associated acute respiratory distress syndrome has become an accepted option, the degree to which it should be used remains controversial.5
Corresponding Author: Johannes Kalbhenn, MD, Faculty of Medicine, Department of Anesthesiology and Critical Care, University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany (johannes.kalbhenn@uniklinik-freiburg.de).
Published Online: January 27, 2021. doi:10.1001/jamasurg.2020.6628
Conflict of Interest Disclosures: None reported.
2.Schmidt
M, Hajage
D, Lebreton
G,
et al; Groupe de Recherche Clinique en REanimation et Soins intensifs du Patient en Insuffisance Respiratoire aiguE (GRC-RESPIRE) Sorbonne Université; Paris-Sorbonne ECMO-COVID investigators. Extracorporeal membrane oxygenation for severe acute respiratory distress syndrome associated with COVID-19: a retrospective cohort study.
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