By Stephen Spotswood
BETHESDA, MD — For Air Force Col. Todd Rasmussen, MD, and Jonathan Eliason, MD, the idea for a new way to treat internal hemorrhaging on the battlefield was hard-won.
It arrived after being exposed time and again to servicemembers bleeding out from internal pelvic and torso injuries at forward operating bases. They saw firsthand how deadly traumatic hemorrhage, the number one cause of combat deaths for U.S. servicemembers, could be. And it was during the gaps between deployments when they realized that solution might exist in technology already commonly used in civilian hospitals.
Rasmussen, now a professor of surgery at the Uniformed Services University and deputy director of the U.S. Combat Casualty Care Research Program at Fort Detrick, did his vascular surgery training at the Mayo Clinic through the Air Force’s Health Professions Scholarship Program. He began what he refers to as a “revolving door of deployments” in late 2004. Over the next several years he would complete tours as a surgeon at Balad Air Base, Iraq (2004, 2008), Bagram Air Base, Afghanistan (2010, 2012), and at the Afghan National Army Hospital in Kabul (2006).
It was at Balad in 2006 that he and Eliason, who is now at the University of Michigan, would first have the idea for what would eventually become REBOA (Resuscitative Endovascular Balloon Occlusion of the Aorta).
“What we observed downrange as the major problem for mortality was bleeding,” Rasmussen explained. “While we had good solutions for extremity hemorrhage, we did not have good options for torso hemorrhage. If there’s an injury to the spleen and it’s hemorrhaging and the patient has 20 to 40 minutes to live, you can’t put a tourniquet on the spleen.”
Their training as vascular surgeons allowed them to see not just the frustrating nature of the problem but possible solutions based on existing vascular technology.
“We had never trained as trauma surgeons,” Rasmussen explained. “Because of that, we had a little bit different viewpoint of vascular control. There’s been a real revolution in how we treat vascular disease—moving from open operations to endovascular devices like stents, balloons, and stent graphs. We would see these new technologies being applied to age-related vascular disease. Then we would see all this bleeding when we were deployed—injury followed by subsequent hemorrhage and shock.”
Both physicians had academic and research backgrounds, and so used their time between deployments to start research programs supported by DoD examining how existing balloon catheters could be redesigned to work in a forward military setting.
“That lightbulb went off and we started to ask questions. What would be the engineering controls? What would the new device have to look like to be used in trauma for younger patients? We drew out and charted goals for the new technology on scratch paper,” Rasmussen explained. “We’d deploy, then come back, ponder what we saw and do small research projects, then deploy again,”
Quite a bit needed to be changed for the technology to be useful in a military setting. To start, the technology was large and required vascular surgeons to operate it. It also required fluoroscopic and Xray units—rarely available in forward surgical units.
“We knew that if it was going to be useful for hemorrhage, we would need to make it more stealth,” Rasmussen said. “Then we wanted to design it so it could be used by a broad range of providers. There are less than a dozen vascular surgeons in the Air Force , but several dozen general and trauma surgeons.”
For the next few years, they developed the device that would eventually be called REBOA. Declaring a patent co-owned between DoD and the University of Michigan, where Eliason is an associate professor of vascular surgery, they built a prototype in 2009. It was “pretty crude” Rasmussen admitted. But it was refined enough to allow tests to be performed on large animal models.
With REBOA, the catheter is inserted into an artery. Then salt water is used to inflate a balloon at the end, closing off the artery and stopping blood flow. It’s a short-term solution, but can stop bleeding long enough for surgeons to stabilize the patient and repair damage.
But after showing proof-of-concept, their effort stalled. Larger medical device companies weren’t interested in investing in REBOA’s production, Rasmussen explained. “We were almost stuck in 2011 and 2012 with just doing research and publishing papers. Which would have been a useful scientific endeavor, but we wouldn’t have gotten this to patients.”
Rasmussen and Eliason introduced the device to private investors who, appreciating the value of the technology, licensed the patent and created Prytime Medical Devices. REBOA was approved by the FDA in 2015 and Prytime began manufacturing the device, which has been on the market for about 18 months.
During that interval, REBOA has been used about a thousand times on patients, most of which have been trauma-related. Of those, a dozen or so have been downrange in Iraq or Syria, Rasmussen said. Each day his inbox has messages from doctors across the country telling him of how they’ve used the device.
“We’ve even had recent use in post-partum hemorrhaging,” Rasmussen explained. “That’s not a surprise. We always knew and recognized that post-partum hemorrhage would be a possible use. That was on our mind when we developed it.”
What they might not have expected was just how disruptive this technology could be.
“Somebody said we kicked quite a hornet’s nest when we developed and commercialized this because it’s a technology that stands to change how hemorrhage and shock is addressed,” he said. “The disruptive part is that it’s likely to be used by the people who we designed it for—emergency medical physicians and primary care doctors, not just the specialists who traditionally lay claim to this sort of maneuver. That means they have to be trained to use it, and there’s a lot of discussion about who should use it and at what level of care.”
Training with the devices is imperative. If the balloon is used incorrectly, or is inflated for too long, it can cause serious complications, even possible amputation. Such complications occur in about 10% of patients. However, doctors see this as an acceptable risk when dealing with patients who are on the brink of death.
“If the device is used in the patients it’s supposed to be used in—patients with end-stage hemorrhagic shock—then even if the patient survives and has complications, that means they survive to have those complications,” Rasmussen said.
The second generation of the device is already being tested, however, and Rasmussen hopes that it will lower the complication rate even further. He also expects to learn more about how the device can be best used in clinical settings through data gleaned from an upcoming multisite DoD study as well as another multi-center study—this one conducted by National Institute for Health Research in the United Kingdom.
While the majority of REBOA’s use will occur in civilian hospitals, hearing of the benefits to military personnel is especially gratifying. “I had an email from a guy downrange—a graduate from here at the Uniformed Services University. He did his surgical training and was immediately deployed,” Rasmussen recounted. “He used the catheter downrange as part of a U.S. Special Operations Surgical Team. That’s not the first or the only email like that, but it’s always very rewarding.”
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