A systematic review and meta-analysis comparing the clinical characteristics and outcomes of COVID-19 and influenza patients on ECMO

Background: Extracorporeal membrane oxygenation (ECMO) is a valuable rescue therapy to treat refractory hypoxemia caused by influenza. The present meta-analysis aimed to compare the clinical characteristics and outcomes of ECMO between COVID-19 and influenza. Methods: We searched the PubMed, Cochrane Library, SCOPUS, and Web of Science databases from inception to May 1, 2021. The included studies compared the clinical characteristics and outcomes of ECMO between adults with COVID-19 and those with influenza. Results: The study included four retrospective cohorts involving a total of 129 patients with COVID-19 and 140 with influenza who were treated using ECMO. Clinical characteristics were similar between the COVID-19 and influenza groups, including body mass index (BMI), diabetes mellitus, hypertension, and immunocompromised status. A higher proportion of patients with COVID-19 on ECMO were male (75.9% vs. 62.9%; P = 0.04). There was no difference between the groups in terms of illness severity based on sequential organ failure assessment (SOFA) score or serum pH. Patients with COVID-19 had a longer mean duration of mechanical ventilation before ECMO (6.63 vs. 3.38 days; P < 0.01). The pooled mortality rate was 43.8%. The mean ECMO duration (14.13 vs. 12.55 days; P = 0.25) and mortality rate (42.6% vs. 45.0%; P = 0.99) were comparable between the groups. Conclusion: Clinical characteristics, ECMO duration, and mortality were comparable between patients with COVID-19 and those with influenza who required ECMO to treat refractory hypoxemia. The duration of mechanical ventilation before ECMO did not influence outcomes. Patients with COVID-19 benefit from ECMO salvage therapy similarly to those with influenza. (C) 2021 The Japanese Respiratory Society. Published by Elsevier B.V. All rights reserved.