Ventilators have failed to help and death looks imminent, but for some of Canada’s sickest COVID-19 patients, there is another, out of-body option.
Several were recently connected to what amounts to an artificial lung sitting next to their beds, technology that has saved at least two people so far.
The extra-corporeal membrane oxygenation (ECMO) machines funnel blood out of the patient and into a device that removes carbon dioxide and adds oxygen, before the fluid is pumped back into the heart and on to the rest of the body.
They would have died otherwise
It’s a resource-intensive “rescue” therapy that only a few hospitals offer. Toronto General is one and it has treated eight COVID-19 patients with ECMO. As of Tuesday, two of them had been removed from the machines and were recovering well.
“They would have died otherwise,” says Dr. Eddy Fan, head of the ECMO program at University Health Network (UHN), which includes Toronto General. “For the right patient, who is dying of ARDS (acute respiratory distress syndrome), ECMO can be very useful.”
But there’s also controversy around the treatment, which Fan admits requires a “huge” team of specialists, a commitment of personnel that may not even be possible amid an Italy-like surge of patients.
One small study found a higher mortality rate in ECMO-treated COVID-19 patients than those who didn’t go on the machine, though its results are considered far from definitive.
The “extreme sport” of ECMO can be justified in rare cases, but for already frail patients and some others it might not achieve much, argues Dr. Yoanna Skrobik, a University of Montreal critical-care medicine professor.
It is “one of the most invasive interventions that can be procured in an intensive care setting,” she said via email. “Giving hope when futility looms, and hoarding so many resources (much more equipment and two bedside staff for that person alone, 24/7), may give one pause before suggesting it routinely as a ‘Hail Mary’ intervention.”
ECMO can be used to take over the function of both the heart and lungs in severely ill patients, but for most COVID sufferers and others who still have sufficient cardiac ability, it does the work only of the lungs
For those people, surgeons attach a tube called a cannula to the right side of the heart. It siphons blood into the machine, cleaning out harmful carbon dioxide and adding oxygen. The blood is then pumped through another cannula back into the heart, which drives it out as usual.
ECMO is typically offered to patients who are not getting better on a ventilator – they’re still suffering from dangerously low blood-oxygen levels – or whose lungs are being damaged by the breathing machine, said Dr. Niall Ferguson, the UHN’s critical care head.
“This will certainly be for a minority, but hopefully can save a few patients who otherwise might have died,” he said.
Its use was “instrumental” in treating patients with severe respiratory distress in the 2009 H1N1 flu pandemic, noted the international Extracorporeal Life Support Organization in a recent report. For that reason and others, its deployment has “increased substantially” over the last decade, says a recent paper by Alberta physicians.
It’s used about 100 times annually at Toronto General, and during one week of the flu season last year “we were going out and cannulating somebody every day,” said Ferguson.
He said there’s little data from Italy and other parts of the world with heavy COVID-19 caseloads, partly because they were so over-run with patients they didn’t have the resources to offer the treatment.
But the paper published recently cast some doubt on the technology’s role in the pandemic. It reviewed published studies on 17 COVID-19 cases — a tiny sample by medical-science standards — and found 94 per cent died, compared to 71 per cent treated conventionally.
ECMO is ‘one of the most invasive interventions that can be procured in an intensive care setting’
“The take-home message is we need to be cautious when deploying ECMO and carefully consider which COVID-19 patients have the best prospects of a positive outcome,” Dr. Brandon Henry, a cardiac intensive care specialist in Cincinnati and co-author of the article, said by email .
Ferguson noted the study looked at a very small number COVID patients, spoke little about their age, health and other characteristics, and had no information about the experience of the hospitals who provided the ECMO — a known factor in its success.
But he said his team, which has the highest volume in Canada, is being particularly careful about which patients receive the treatment.
“We don’t want to use ECMO as a prolongation of dying,” said Ferguson, “as opposed to making people more healthy.”