ECMO involves connecting tubes to the patient's circulatory system to bring blood outside the body and into a circuit that oxygenates and filters the blood before pumping it back into the body. Courtesy of University of Michigan
Ventilators have gotten a lot of attention in the ongoing fight against COVID-19. But hundreds of hospitals around the world have another, less-publicized weapon that might help some of the most desperately ill patients survive when ventilators aren’t enough.
Right now, hundreds of COVID-19 patients in intensive care worldwide are being kept alive using a life support technology called ECMO and the skills of specially trained teams of nurses, respiratory therapists, technicians and doctors.
Meanwhile, experts are tracking in real time how well ECMO works in treating COVID-19. But early indications are that it could offer a last chance at life for a subset of the sickest COVID-19 patients: those who were relatively young and healthy before becoming infected with the novel coronavirus.
Early evidence, based on a rapidly evolving international registry, shows that more than a third of critically ill COVID-19 patients who have completed ECMO treatment survived and left the hospital alive. Without ECMO, most would probably have died.
With more time and data, it will be possible to see if ECMO saves as many people as it did during the H1N1 flu pandemic of 2009, when 60% of the patients critically ill enough to need ECMO were able to survive the viral infection.
Short for extracorporeal membrane oxygenation, ECMO involves a complex circuit of pumps, tubes, filters and monitors that must be operated by an expert team, to take over for both the heart and lungs. It channels the patient’s blood outside their body in order to add oxygen and remove waste before propelling it back to into the circulation system.
Major medical centers, including the University of Michigan’s Michigan Medicine, have used ECMO for decades as a last-chance treatment for patients ranging from infants with heart malformations to adults with lung failure. Robert Bartlett, M.D., now an active emeritus professor of surgery at U-M, led the development of modern ECMO starting in the early 1980s, and has become known worldwide as the “grandfather of ECMO.”
In the past decade, ECMO’s use has grown rapidly. More than 400 hospitals worldwide are listed in a registry of ECMO centers, up from about 120 centers 20 years ago. Additional hospitals have also added the capacity but are not yet part of the registry.
Now, ECMO is being used in certain COVID-19 patients. But experts caution that patients must get evaluated by an ECMO center and transferred before their condition worsens too much. They should not have been on a ventilator more than seven days before starting ECMO, which means that they should be considered for ECMO soon after the decision to intubate them is made.
Seven of the eight patients on ECMO at Michigan Medicine as of mid-April were COVID-19 patients, and most had transferred from hospitals in Detroit and its suburbs.
“Despite the substantial resources required to care for patients on ECMO, we believe this is an appropriate strategy for selected patients that are otherwise at imminent risk of death,” says Jonathan Haft, M.D., medical director of U-M’s ECMO program. He adds that so far, the outcomes for ECMO patients treated by U-M’s team appear to be similar to outcomes from treating patients with other causes of acute respiratory failure.
The U-M academic medical center treats more than 100 patients using ECMO every year, making its program among the largest in the country. The city where U-M is based, Ann Arbor, also serves as the headquarters of the Extracorporeal Life Support Organization, or ELSO, the international group that provides support and shared resources for ECMO care, and tracks and analyzes data to improve care.
Through a massive and rapid effort by staff, ELSO has built a real-time dashboard of data on patients placed on ECMO for COVID-19 since March.
As of April 21, it shows that more than 470 patients with suspected or confirmed cases of COVID-19 have been treated at the ECMO centers that are sharing their data. Most were men in their 40s and early 50s. Nearly half had obesity and one-fifth had diabetes.
Most of those placed on ECMO for COVID-19 are still on the treatment, which can take weeks to allow the body to recover enough for the patient to function on their own. Every moment of that time, patients must be under the care of teams of trained nurses, respiratory therapists, technicians and physicians.
In March, Bartlett and his colleagues created guidance for the use of the treatment in COVID-19, to help centers with existing ECMO capability understand when to devote resources to providing this level of care, and which patients to prioritize. They do not recommend that hospitals set up a new ECMO program in the middle of a pandemic.
“If a patient is on a ventilator, and failing to respond, and they are relatively young with few comorbidities, that’s the time to think about ECMO,” says Bartlett.
Sharing real-time data from ECMO centers around the world has been brought emerging data to frontline providers searching for information on ECMO and COVID-19, says Ryan Barbaro, MD, MS, the U-M pediatric intensivist who leads the ELSO Registry program.
“We don’t know yet what the survival rate will be for ECMO-supported patients with this virus, but,” he says. “Sharing what we do know as the information is accumulated has been a valued resource for those considering ECMO support in patients with COVID-19.”
Lena Napolitano, MD, co-directs the Surgical Intensive Care Unit where U-M’s adult ECMO patients are cared for, and is director of surgical critical care at Michigan Medicine. “ECMO centers provide an opportunity for patients to recover that not all institutions have, but it’s important to use this approach in the correct patient population,” she says. “It’s also important that centers without ECMO contact ECMO centers about evaluating COVID-19 acute respiratory distress syndrome patients for transfer as early as possible.”
Michigan Medicine’s air ambulance service, Survival Flight, is equipped to provide ECMO in-flight, and its flight nurses are trained in critical care – making U-M’s helicopters flying intensive care units.
Napolitano notes that in the face of a pandemic such as COVID-19, ECMO centers maybe limited not by how many ECMO circuits they have, but by how many trained staff they have available to provide the around-the-clock intensive care patients need.
That’s what makes early consultation and timely transfer of appropriate patients so important, she says. Even if the patient does get transferred to an ECMO center, they may not be put on ECMO immediately, because ECMO centers may also offer additional types of advanced care.
“If the patient has the full capacity to recover, the disease itself is recoverable,” she says. “In general, viral pneumonia has the best survival rate of all the indications for which we use ECMO, so it’s important we consider it in these patients too.” Even those with acute kidney injury and septic shock can recover from COVID-19, she adds.
Napolitano emphasizes the critical role of nurses, respiratory therapists and physician trainees including residents and fellows in the tireless response to the current level of ECMO care for COVID-19 patients. Even medical students are playing a role, volunteering to keep families informed several times each day about how their loved ones are doing via phone when they cannot visit.
Barbaro notes that even with seven ECMO patients at one time, U-M has one of the largest COVID-19 ECMO populations in the world. The median number of simultaneous cases at other hospitals is around three. About 100 of the centers that belong to ELSO say they have taken care of a COVID-19 patient using ECMO.
Even as U-M and other hospitals provide ECMO care to COVID-19 patients, they’re taking care to ensure that circuits and staff are available for patients who need the technology for other types of care.
The registry will help Bartlett, Barbaro and their colleagues gather enough data to publish findings soon, after the first hundred or so patients have completed their course of care. Even the patients who do not survive will provide valuable clues to help clinical teams in future.
The COVID-19 data add to the data on more than 120,000 ECMO patients already in the registry.
Meanwhile, past patients who owe their lives to ECMO continue to send messages to Bartlett. But he’s characteristically humble about this attention. “We’re just taking care of sick people, and we’ve figured out a way to help them live a little longer,” he says.
Source: University of Michigan