The call came in at 3:11 a.m.: The family of a 40-year-old man discovered him unresponsive, breathing irregularly and convulsing. First responders recognized he was in cardiac arrest and quickly started CPR and applied an AED. After two shocks paramedics arrived. The patient’s heart remained in ventricular fibrillation—they prepared to shock him again. Fifteen minutes had elapsed since the initial 9-1-1 call.
In most communities this scene would unfold in a fairly similar fashion: Paramedics would follow the ACLS algorithm for VF, administering shocks and medications such as epinephrine and amiodarone. They would remain on scene to ensure continuous chest compressions, manage the airway, and closely monitor the cardiac rhythm. At some point—either after return of spontaneous circulation or a prolonged period of nonshockable rhythm—they would transport the patient to the hospital or terminate resuscitation. The patient’s chance of survival would be no more than 15% and probably less.1–4
That was how we used to treat patients like this one in the Twin Cities as well. The best evidence at the time indicated uninterrupted chest compressions and defibrillation—two interventions best performed on scene, not in a moving ambulance. Until EMS achieved a stable pulse in its patient, there was little emergency physicians, cardiologists, and surgeons could do differently to save them.
But as new evidence suggested that extracorporeal membrane oxygenation—better known as ECMO—could give these patients more hope, we formed a unique system of care specifically aimed at improving survival for patients with refractory shockable rhythms.
The theory behind ECMO for refractory shockable rhythms is well established and has been described in many publications.5,6 ECMO involves the cannulation of a major artery and vein and use of a device that both pumps the blood and facilitates oxygen and carbon dioxide exchange—in other words, it establishes a temporary external artificial heart and lungs.
In cardiac arrest this stabilizes the patient, which allows for the identification and treatment of reversible causes of the arrest that cannot be addressed through typical ACLS measures. For many patients found in shockable rhythms who are not resuscitated successfully in the first few minutes, that cause is a coronary occlusion. Putting those patients on ECMO buys time, perfusing the brain and other organs while the occlusion is identified and removed in the cath lab.
Several communities around the world have begun using ECMO for the treatment of cardiac arrest in the hospital and even in the field. Until recently, however, no large trials had compared the effectiveness of ECMO to standard ACLS treatments. In November 2020 we published the results of the ARREST trial in The Lancet.7 The trial randomized refractory ventricular fibrillation patients into two groups when they arrived at the hospital, an ECMO group and a standard ACLS group. The benefits of ECMO were clear: Survival to hospital discharge in the ACLS group was 7%, compared to 43% in the ECMO group. Each survivor in the ECMO group was still alive with good neurological outcomes six months after their cardiac arrest.
ECMO proved so successful at improving outcomes for these patients that a board monitoring the trial ended it early, saying it would no longer be appropriate to randomize patients to the non-ECMO group and decrease their chances of survival. That means ECMO is now the standard of care for refractory VF cardiac arrest patients in the Twin Cities. But how do we ensure more patients can get access to that treatment?
The Mobile ECMO Program
We began our ECMO program in 2015 at a single facility. Refractory VF patients who met the criteria for ECMO were transported to the University of Minnesota Medical Center (UMMC) in downtown Minneapolis, where they were immediately placed on ECMO and taken to the cath lab. We saw the benefits of ECMO but also realized the limitations of having this lifesaving capability at only one hospital. When ECMO began within 30 minutes of the initial 9-1-1 call, patients had a great chance of survival; as time to cannulation increased, survival decreased. That limited the impact of this intervention to a small number of patients who went into arrest where responders could reach them immediately and quickly get them to UMMC.
A handful of systems around the world have created mobile ECMO programs to expand the reach of ECMO; many of those programs have teams respond to scenes and cannulate patients wherever they are found. Others use specialized ambulances. The Minnesota Mobile Resuscitation Consortium, a nonprofit formed to bring together stakeholders to make the ECMO program a reality, took a multiphase approach.8
The initial phase of our mobile ECMO program began in December 2019. Mobile ECMO teams consisted of three members: two physicians to perform the cannulation and a critical care nurse or paramedic to assist. The teams went through rigorous training that included clinical and operational didactic components as well as simulation. Team members also received emergency vehicle operator training to drive the program’s chase vehicles.
The three-person ECMO teams took 24-hour shifts on call. When a crew in the field notified the dispatch center they had a patient for ECMO, the team would be activated and respond in one of the program’s specially equipped SUVs to meet the patient and crew at one of three designated emergency departments, based on transport time.
EMS crews took patients to one of the three ECMO centers based on simple criteria:
The patient was between 18–75 years old;
Their initial presenting rhythm was VF or ventricular tachycardia (or initial AED analysis advised shock);
Two shocks given without return of spontaneous circulation;
An automated mechanical CPR device could be used;
Estimated arrival at the ED in 30 minutes or less.
On arrival at the hospital, the ECMO team would start preparing to cannulate the patient. The ED team would continue resuscitation while also assessing the patient’s end-tidal CO2, arterial oxygen levels, and lactic acid levels to ensure they still met the parameters for continued resuscitation and ECMO. After cannulation the patients were taken to the cardiac cath lab for coronary angiography and, if indicated, percutaneous coronary intervention. Patients treated at either of the two nonuniversity hospitals were then transferred to the ECMO ICU at UMMC for postarrest care.
In the first four months of the program, 58 refractory VF patients met the initial screening criteria for ECMO. Several were not cannulated because they failed to meet criteria for continued resuscitation. ECMO cannulation was attempted in 45 patients, all of whom were successfully cannulated with initiation of ECMO support. After stabilization they were taken to the cardiac cath lab. Of those 45 patients, 27 survived to hospital discharge, and 25 of those had good neurological outcomes—a remarkable rate of 43%, confirming that the results of the ARREST trial could be replicated in a multihospital mobile ECMO team model.
Phases 2 and 3
The faster a cardiac arrest patient is put on ECMO, the greater their chance of survival. Creating mobile ECMO teams to respond to established ECMO EDs is one way of doing that. The next phase is the deployment of a self-contained mobile ECMO unit that can meet EMS at the scene of the arrest or a rendezvous point.
The mobile ECMO unit is a unique new design. Larger than an ambulance, the vehicle is equipped with extensive telemedicine capabilities, a small lab, and fluoroscopy and ultrasound to facilitate safe and rapid cannula placement. When Phase 2 launches the ECMO truck will meet EMS outside the destination hospital, and the procedure will take place inside the truck, providing an opportunity to test the truck’s capabilities and fine-tune the process. Phase 3 will take the truck into the field, meeting EMS crews and patients at established rendezvous points to decrease the time from arrest to cannulation. Once patients are successfully on ECMO, they will be transported by ambulance to UMMC for postresuscitation care.
‘Load and Go’ Mind-Set
Generally EMS has accepted the dogma that cardiac arrest is a “stay and play” event, and any patient movement causes interruptions in CPR and delays in defibrillation and other critical interventions. Over the last five years, one of the most significant challenges faced by the Minnesota mobile ECMO project has been trying to change that mind-set. Now as soon as the first shock fails to achieve ROSC, EMS clinicians recognize the need to move quickly. As one of our team members puts it, we treat VF “almost like a gunshot wound to the chest.”
Putting the Patient First
It required immense collaboration and coordination to make the Minnesota mobile ECMO project successful. Fortunately the University of Minnesota Center for Resuscitation Medicine had already established considerable cooperation between EMS organizations, the emergency medicine community, and cardiologists with shared interest in improving cardiac arrest outcomes.
Before implementation three independent hospital systems, typically competitors, had to agree to set that aside and work together to make this possible. We determined early that having multiple ECMO programs would not create ideal outcomes. The commitment of these hospital system leaders to patients and the community made the program possible. One critical piece of that was establishing an independent nonprofit entity, the Minnesota Mobile Resuscitation Consortium, and including representatives from each hospital system on its board. In addition, clinicians from all three systems staff the mobile ECMO team, with each credentialed to practice in all the ECMO cannulation sites.
While ECMO is clearly a critical new link in the chain of survival, an ECMO program can only succeed as part of a high-performing cardiac arrest system of care—from early recognition by witnesses and emergency telecommunicators to postarrest rehabilitation. For us other critical aspects of that system include:
High-performing first response and EMS services with a passion for patient-centered, evidence-based care;
Use of mechanical CPR to ensure high-quality compressions can be performed during patient movement and transport;
A small, dedicated team of ECMO specialists to assure a patient volume that maintains skill competence;
A single dedicated ECMO ICU prepared to provide postresuscitation care for patients who typically have significant damage to multiple organ systems.
A Life Saved
Instead of staying on scene futilely trying to resuscitate our 40-year-old victim described at the beginning of this article, the paramedics who arrived on scene quickly recognized a potential ECMO patient. Immediately the crew split up responsibilities: One took the lead on patient care, working with the first responder crew to continue resuscitation and place the patient on a LUCAS CPR device. The other crew members began preparing for transport and notifying the mobile ECMO dispatcher. Within minutes the ECMO team began responding to the emergency department, and EMS moved the patient to the ambulance, where they established an advanced airway and IO access. During transport they continued ACLS treatment, administering amiodarone and delivering several more shocks, the sixth and final just as they arrived at the hospital—40 minutes after the initial 9-1-1 call.
Ten minutes later the patient was on ECMO and on his way to the cath lab, where the team found a 100% occlusion of his distal right coronary artery. After removing the lesion the team transferred the patient to UMMC and the ECMO ICU. Less than two weeks later, he left the hospital to return home with no need for any additional rehabilitation services.
The 43% survival rate for refractory VF we have achieved with ECMO means many more stories like this one—more people back home with their families and back at work helping their communities. ECMO is the new standard of care for these patients in the Twin Cities, with the new mobile ECMO truck meaning even more patients will have earlier access to this critical treatment, and even more Minnesotans will survive this devastating disease.
1. Yannopoulos D, Bartos JA, Martin C, et al. Minnesota resuscitation consortium’s advanced perfusion and reperfusion cardiac life support strategy for out-of-hospital refractory ventricular fibrillation. J Am Heart Assoc, 2016; 5(6): e003732.
2. Yannopoulos D, Bartos JA, Raveendran G, et al. Coronary Artery Disease in Patients With Out-of-Hospital Refractory Ventricular Fibrillation Cardiac Arrest. J Am Coll Cardiol, 2017 Aug 29; 70(9): 1,109–17.
3. Kudenchuk PJ, Brown SP, Daya M, et al. Amiodarone, lidocaine, or placebo in out-of-hospital cardiac arrest. N Engl J Med, 2016; 374(18): 1,711–22.
4. Bartos JA, Grunau B, Carlson C, et al. Improved survival with extracorporeal cardiopulmonary resuscitation despite progressive metabolic derangement associated with prolonged resuscitation. Circulation, 2020; 141(11): 877–86.
6. Bailey L, Pruett K, Braude D. ECMO comes to the field. EMS World, 2019 Dec 13; www.emsworld.com/article/1223660/ecmo-comes-field.
7. Yannopoulos D, et al. Advanced reperfusion strategies for patients with out-of-hospital cardiac arrest and refractory ventricular fibrillation (ARREST): a phase 2, single centre, open-label, randomised controlled trial. Lancet, 2020 Dec 5; 396(10,265): P1807–P1816.
8. Bartos JA et al. The Minnesota mobile extracorporeal cardiopulmonary resuscitation consortium for treatment of out-of-hospital refractory ventricular fibrillation: Program description, performance, and outcomes, EClinicalMedicine (2020), https://doi.org/10.1016/j.eclinm.2020.100632.
Sidebar: Minnesota Mobile ECMO Program Excites Its Funders, the Helmsley Charitable Trust
Even for an organization that has given out more than $2.5 billion in grants, the $18.5 million the Helmsley Charitable Trust awarded to the University of Minnesota in 2018 was a big deal. It’s the largest award ever given by the trust’s Rural Healthcare program, which aims to increase access to high-quality healthcare in the Upper Midwest.
“We are so excited about the Minnesota mobile ECMO program,” says Walter Panzirer, one of the Trust’s trustees and a former paramedic, firefighter, and police officer. “The success rates speak for themselves. This will become a model for the rest of the nation and around the globe.”
This isn’t the first foray into emergency medicine or EMS for the Helmsley Charitable Trust. Previous recipients of funding from the organization have used the awards to support mobile simulation training programs, purchase mechanical CPR devices, and enhance stroke systems of care.
The goal of the grant is not only to demonstrate the efficacy of the rapid ECMO program but also to find ways to make it sustainable in the long term. Sustainability is a priority for the program, and its leaders have worked closely with the hospitals involved to make sure they can bill adequately for their services and providers.
For more information about the Helmsley Charitable Trust and the programs it supports, visit helmsleytrust.org.
Demetri Yannopoulos, MD, is a professor of medicine with the Center for Resuscitation Medicine at the University of Minnesota. He is board certified in internal medicine, cardiology, and interventional cardiology.
Jason A. Bartos, MD, PhD, is an assistant professor of medicine at the University of Minnesota. He is board certified in internal medicine, cardiology, critical care medicine, and interventional cardiology.
The Minnesota Mobile Resuscitation Consortium is an independent community consortium owned by healthcare systems with a mission to implement a rapid-response medical strategy to provide Minnesota the highest survival in the world from out-of-hospital cardiac arrest. The consortium was developed as part of the mobile ECMO project funded by the Helmsley Charitable Trust. Learn more about the program at med.umn.edu/dom/research/programs-centers/center-resuscitation-medicine.