ABSTRACT
Introduction: The impact of treatment experience with ECMO prior to the COVID-19 pandemic era on the outcomes of ECMO during the COVID-19 pandemic has not been well investigated. The aim of this study was to investigate the differences in the outcomes of ECMO between highvolume hospitals in Japan before the COVID-19 pandemic and low-volume hospitals. Method(s): This is a prospective observational cohort study of patients with fatal COVID-19 pneumonia in Japan receiving ECMO. The association between patient background, high/low-volume hospitals, and survival from February 2020 to November 2021 were evaluated. Prognostic factors were assessed by Kaplan-Meier and Cox proportional hazards analyses. High-volume hospitals were defined as those with a total of at least 20 cases prior to the COVID-19 pandemic era. Result(s): Ten hospitals (1.1% of a total of 900 ICUs in Japan) were classified as high-volume hospitals, with a median number of ECMO cases of 35.5 (IQR, 25.5-40.5). There were a total of 1,214 ECMO cases during the COVID-19 pandemic, of which 1030 (85%) were treated in low-volume hospitals and 184 (15%) were treated in high-volume hospitals. Kaplan-Meier analysis demonstrated slightly better survival in high-volume hospitals in 30-day (p=0.062) and 60-day (p=0.11) survivals, whereas, in 90-day survival, the two groups were almost identical (p=0.87). Cox proportional hazards analysis also failed to demonstrate that high-volume hospital before the COVID-19 pandemic era was independent prognostic factor (HR, 0.97;95%CI, 0.74-1.28). Conclusion(s): In Japan, high-volume hospital prior to the COVID-19 pandemic era was not independent prognostic factor.