Life-support system reduced COVID-19 mortality by 7.1%, study shows
An international observational study published in the British Medical Journal showed ECMO has a significant impact in saving lives of the sickest COVID-19 patients.
A new study published in the British Medical Journal (BMJ), led by the COVID-19 Critical Care Consortium (COVID Critical), showed that Extracorporeal Membrane Oxygenation (ECMO), a life-support system used extensively during COVID for patients with acute respiratory failure, was associated with a reduction in mortality by 7.1% when compared with mechanical ventilation alone.
During the pandemic, ECMO has been used 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*.
Authors of the study, full title Venovenous extracorporeal membrane oxygenation in patients with acute COVID-19 associated respiratory failure: comparative effectiveness study, were invited to present the paper as part of a “late breaking” session at the 10th Annual Congress of the European Chapter of the Extracorporeal Life Support Organisation (EuroELSO) in London earlier this month.
This was the largest international, registry-based cohort study looking into ECMO effectiveness to treat acute respiratory failure caused by COVID-19^. Together with the COVID Critical dashboard to be released in 2022, the study published in the BMJ is one of the major legacy pieces of the international humanitarian project.
“This paper is one of the most important recent studies in our field and sets a precedent for the way observational data can be rigorously evaluated and disseminated,” said Professor Daniel Brodie, President-elect, Extracorporeal Life Support Organization (ELSO) and Chair of the Executive Committee of the International ECMO Network (ECMONet).
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 (ECLS) at University Health Network (UHN), Toronto. He said this high-impact study was only made possible by the global alliance of healthcare professionals and researchers behind COVID Critical.
Figure 1
Treatment with extracorporeal membrane oxygenation (ECMO) if ratio of partial pressure of arterial oxygen to fraction of inspiratory oxygen (PaO2/FiO2) was <80 mm Hg, was compared with treatment with conventional mechanical ventilation without ECMO. Adherence adjusted estimates are reported for differences in hospital mortality and probability of hospital discharge alive in 7345 patients with covid-19 associated acute respiratory failure. Shaded areas represent 95% confidence intervals.
“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 have been able to take millions of datapoints collected by COVID Critical and use the data in such a way to model a randomised controlled trial (RCT) of ECMO distribution and close this knowledge gap,” said Dr Fan.
First author, clinical and research fellow in Critical Care Medicine at UHN, Dr Martin Urner said by using advanced statistical methods to model a RCT, the team was able to quantify the effect of ECMO therapy 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.
Figure 2
As treated analysis in 7345 patients, with hospital mortality compared between treatment as received, which could have included treatment with extracorporeal membrane oxygenation (ECMO), and treatment with conventional mechanical ventilation without ECMO. Shaded areas represent 95% confidence intervals.
Figure 3
Treatment with extracorporeal membrane oxygenation (ECMO) if ratio of partial pressure of arterial oxygen to fraction of inspiratory oxygen (PaO2/FiO2) was <80 mm Hg compared with conventional mechanical ventilation without ECMO. Adherence adjusted effects (95% confidence intervals) on hospital mortality within 60 days reported by age groups and baseline comorbidities.
COVID Critical Co-Founder Professor John F Fraser said Drs Fan and Urner have taken his challenge to work with this ‘big data’ alongside COVID Critical’s lead statisticians Drs Adrian Barnett and Nicole White. “This international team did an amazing job of ‘cracking the code’, analysing observational data from 65 countries in a revolutionary way mimicking an RCT which could never have been completed during the chaos of a pandemic.”
“The way in which the data has been used is a world-first. We’ve taken the largest known resource of deidentified patient data and interrogated it to shed new light on COVID-19 and associated ARDS mortality and treatment options,” said Professor Fraser.
BACKGROUND
Founded in January 2020 by Professor Fraser, Associate Professor Gianlugi Li Bassi and Dr Jacky Suen, the COVID-19 Critical Care Consortium consists of 400+ collaborating centres in 64 countries, contributing data to the world’s largest known database of COVID-19 ICU patient information. COVID Critical uses this data to generate clinical insights about a disease that was completely unknown before January 2020, revolutionising the way deidentified data can be safely and securely shared across the world.
This study 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.
* Particularly for patients aged 65 years or younger with severely impaired gas exchange (characterised by very low blood oxygen levels despite maximal support with mechanical ventilation) or exposure to higher intensities of mechanical ventilation in the early phase of the disease course.
^ The study compared outcomes of 7,345 adult patients admitted to intensive care units with clinically suspected or laboratory confirmed case of COVID in 30 countries.