A study published in the British Medical Journal, led by UHN researchers and the COVID-19 Critical Care Consortium (COVID Critical), showed that the artificial heart-lung bypass system ECMO (Extracorporeal Membrane Oxygenation) was associated with a reduction in COVID-19 mortality by 7.1% compared with mechanical ventilation alone.
During the pandemic ECMO was used around the world as a last-resort intervention to save some of the sickest COVID-19 patients. This study is the first to demonstrate that it provides a significant benefit in acute respiratory failure due to COVID-19, particularly for patients that are less than 65 years old with severely impaired gas exchange or exposure to higher intensities of mechanical ventilation in the early phase of the disease.
This was the largest international, registry-based cohort study looking into ECMO effectiveness to treat acute respiratory failure caused by COVID-19. It compared outcomes of 7,345 adult patients admitted to intensive care units with clinically suspected or laboratory confirmed case of COVID-19 in 30 countries.
The senior author of the study is Dr. Eddy Fan, a Scientist at the Toronto General Hospital Research Institute and Medical Director of the Extracorporeal Life Support Program at UHN. He says this high-impact study was made possible by the global alliance of health care professionals and researchers behind COVID Critical.
"Less than two years ago, the world had no data, no information on how effective ECMO was in treating patients with COVID-related severe acute respiratory failure. With this study, we were able to take millions of datapoints, use the data to mimic a randomised controlled trial and close this knowledge gap," says Dr. Fan, who is also an Associate Professor of Medicine at the University of Toronto.
Dr. Martin Urner, the study's first author, and a clinical and research fellow in Critical Care Medicine at UHN, said by using advanced statistical methods to model a randomized clinical trial, the team was able to quantify the effect of ECMO on outcomes of adult patients with COVID-19, compared to treatment with mechanical ventilation alone.
"The findings provide evidence that ECMO is a highly effective and lifesaving therapy for well-selected patients with catastrophic forms of lung failure from COVID-19," said Dr. Urner, who is also a PhD candidate in Clinical Epidemiology and Health Care Research at the Institute of Health Policy, Management and Evaluation at the University of Toronto.
According to COVID Critical Co-Founder John F. Fraser, Drs. Fan and Urner have taken "big data" and working with COVID Critical's lead statisticians Drs. Adrian Barnett and Dr. Nicole White, have "cracked the code" to analyse observational data in a revolutionary way to mimic a randomized clinical trial, which could never be done in a clinical setting.
"The way in which the data has been used is a world-first," says Dr. Fraser. "We've taken the largest known resource of deidentified patient data and interrogated it to shed new light on COVID-19 and associated ARDS (acute respiratory distress syndrome) mortality and treatment options."
The COVID-19 Critical Care Consortium consists of more than 400 collaborating centres in 64 countries, contributing data to the world's largest known database of COVID-19 ICU patient information. To read more about the consortium, click here.
This work was supported by the COVID-19 Critical Care Consortium, the International Severe Acute Respiratory and Emerging Infection Consortium (ISARIC), the Short Period Incidence Study of Severe Acute Respiratory Infection (SPRINT-SARI) network, the Extracorporeal Life Support Organization, the International ECMO Network and the UHN Foundation.
Martin Urner, Adrian G Barnett, Gianluigi Li Bassi, Daniel Brodie, Heidi J Dalton, Niall D Ferguson, Silver Heinsar, Carol L Hodgson, Giles Peek, Kiran Shekar, Jacky Y Suen, John F Fraser, Eddy Fan, the COVID-19 Critical Care Consortium Investigators. Venovenous extracorporeal membrane oxygenation in patients with acute covid-19 associated respiratory failure: comparative effectiveness study. BMJ 2022; 377. https://doi.org/10.1136/bmj-2021-068723. 04 May 2022.