Adding oxygen to blood using ECMO process found to cause big increase in survival rate in severe UK cases

By Denis Campbell 

Scores of severely ill Covid-19 sufferers survived because they were given the NHS’s highest form of intensive care in which an artificial lung breathes for them, a study has found.

Patients in the UK who underwent extracorporeal membrane oxygenation (ECMO) were more likely to survive than those who did not have the treatment, according to the research.

People whose breathing capacity had collapsed were more likely to stay alive if they had ECMO rather than only a spell on a mechanical ventilator.

That is the key finding of an analysis of 1,363 people treated for severe Covid using a ventilator in the UK in between March 2020 and February 2021. They included 243 who were taken by ambulance to either Guy’s and St Thomas’ or the Royal Brompton and Harefield hospital trust in London to try to save their lives using ECMO.

The other 1,120 were known as what doctors called “perceived futility” cases – those it was deemed inappropriate to put on ECMO because they were considered too old and sick to survive Covid, and ECMO was thought unlikely to change their outcome. Doctors also had to consider who would benefit most from the limited availability of artificial life support, which is costly and labour-intensive, at the two specialist centres.Sign up to First Edition, our free daily newsletter – every weekday morning at 7am

The 243 were matched by computer analysis for their similarity of personal profile and symptoms with 206 of the 1,120 patients who did not receive ECMO to compare their outcomes.

During ECMO, blood is taken out of the unconscious patient’s body, put into an oxygenator, has oxygen added and carbon dioxide removed, and is then reinserted into the patient. The hope is that the extra oxygen will improve patients breathing enough to help them pull through.

“ECMO had a substantial effect at saving lives in the UK. Lives were saved due to the significant effort on the part of NHS staff to ramp up ECMO provision to provide service for as many [patients] as possible,” said Dr Luigi Camporota, a consultant in intensive care medicine at Guy’s and St Thomas’ who was one of the co-authors.

“Our findings suggest that ECMO delivery at specialist SRF [severe respiratory failure] centres confers significant survival benefit, compared to matched patients who received conventional therapy in referring centres,” he said.

NHS bosses believe ECMO saved several hundred lives during the pandemic.

Prof Stephen Powis, NHS England’s national medical director, said: “This study is a testament to the incredible hard work of NHS staff over the last two years who have treated more than 700,000 Covid-19 patients in hospital including on ECMO machines, which have helped save hundreds of lives.”

The survival from Covid thanks to ECMO seen in the study is higher than in other studies of its use conducted in other countries. However, the results are not directly comparable because of differences between them such as in the selection criteria for deciding which patients received ECMO and whether people were treated in a general hospital or specialist centre, such as the two hospital trusts in the capital.

In this study, 22.9% of the ECMO and 52.9% of the non-ECMO patients died during the first wave of Covid. Mortality rose in both during the second wave, which occurred during winter 2020-21, to 26.1% and 62.4% respectively.

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