In an effort to hasten care for patients in cardiac arrest, researchers at the University of Minnesota are studying whether they can cram ambulances with the latest imaging and heart-lung bypass technology — a breakthrough that would make them better equipped than some small hospitals.
If “super ambulances” could shave minutes off the time it takes to treat a patient whose heart has stopped beating because of blocked arteries or strokes, they could dramatically improve survival odds, said Dr. Demetri Yannopoulos, director of the university’s Minnesota Resuscitation Consortium, a group of hospitals and EMS agencies that collaborate on cardiac arrest care.
“We want to minimize the time … to receive a lifesaving intervention,” he said.
This month the U received a grant of nearly $900,000 from the Leona M. and Harry B. Helmsley Charitable Trust’s Rural Healthcare Program to work on the concept.
The consortium, which includes the university and five ambulance agencies, has already boosted survival rates for some patients by prioritizing transport to the hospital for surgery over continued life-support efforts at the scene. But Yannopoulos said further progress requires getting patients to treatment even faster.
Equipping ambulances with doctors and advanced technology is an emerging concept. More than a dozen U.S. hospitals have deployed stroke ambulances, which carry CT scanners to determine in transit why patients have lost blood flow to the brain. In Paris, ambulances emblazoned with “reanimation” on their hoods carry heart-lung bypass pumps to take over when patients’ hearts have stopped.
But the Helmsley grant would allow the university to study something new: an ambulance with CT scanners and heart-lung bypass equipment and more.
“These super ambulances could be game-changing for people suffering from cardiac arrest,” said Walter Panzirer, a Helmsley trustee.
A decade ago, the concept would have been unthinkable because CT scanners and bypass machines would have been too large to fit on anything smaller than an 18-wheeler. Even now, the vehicles will have to be larger than most ambulances, raising questions about their maneuverability in urban areas and whether they’d fit in a conventional hospital garage.
“I’m not sure I’m even going to call them ambulances,” said Yannopoulos, adding that they might end up being middleman vehicles that receive patients from standard ambulances.
“They’re more like an emergency department substation that’s mobile.”
The challenges go beyond vehicle design. Researchers will need to propose a staffing rotation for the specialized doctors who would need to be on board. And they’ll need to figure out where to deploy the ambulances — finding gaps in and around the Twin Cities where patients who suffer cardiac arrest aren’t getting to hospitals as quickly as others.
Eventually, researchers also will need to prove that souped-up ambulances save patients. The jury remains out on stroke ambulances, which cost as much as $1 million and another $1 million per year to operate.
Studies have found that these ambulances substantially reduce the time between first emergency contact with a stroke patient and the initiation of treatment — often with clot-busting drugs. But a 2016 study in Berlin found that patients receiving standard care were no more likely to suffer hemorrhages or deaths within seven days than those receiving mobile care.
“That is a very expensive resource that is designed to treat a very specific condition,” said Dr. Aaron Burnett, assistant EMS medical director at Regions Hospital in St. Paul and Minnesota state EMS medical director. “There’s a lot of times when something can look like a stroke and then you get the ambulance out there and it’s something different.”
The super ambulance would be designed to work with a unique approach to cardiac arrest developed by the Minnesota consortium. (The consortium includes EMS agencies from Allina, HealthEast, HealthPartners, North Memorial and the city of St. Paul.)
Rather than continue resuscitation efforts at emergency scenes indefinitely, medics in the consortium are trained to transport patients to the U for potential placement on bypass machines if three rounds of defibrillation fail to shock their hearts into normal rhythms.
On board the ambulance, medics use automated CPR machines so they can continue resuscitation while en route. Burnett said that is somewhat controversial, because some studies find manual CPR to be superior.
However, the consortium’s approach has resulted in survival for more than 40 percent of patients whose hearts couldn’t be restarted by defibrillation. They instead go on a bypass machine, which keeps them alive while doctors surgically open up the blood vessel blockages that led to their arrests. Yannopoulos said survival with standard care for this group of cardiac arrest patients has been less than 10 percent.
All patients have survived so far with little or no loss in brain function if they were placed on bypass within 40 minutes of their 911 calls, he added. Trouble is, many don’t reach the hospital that quickly — fueling the desire for super ambulances.
“Most of the people arrive to my cath lab within 55 to 60 minutes,” Yannopoulos said. “We haven’t lost a patient under 45 minutes. So the goal is to get to the patients within half an hour.”
A super ambulance isn’t the only solution. More hospitals could add the capability of using bypass machines during emergency surgeries to open up clogged arteries, Burnett said.
Hennepin County Medical Center in Minneapolis does not follow this protocol but has made its own gains by empowering medics to determine the likely causes of cardiac arrests and to alert surgery teams at hospitals to prepare for patients. They also are using a locally developed ResQPod mask that has improved CPR.
The results of the super ambulance research will be interesting, said Mike Trullinger, deputy chief of operations for Hennepin EMS, but he stressed that it’s still important for the public to know initial CPR and proper chest compression techniques.
“We can bring all our advanced care,” he said, “but if nobody has done anything for five or even 10 minutes, depending on how far away we are, the patient’s chances of survival are very very low.”