Houston hospital leads efforts to use internal tourniquets
HOUSTON— Ejected from his motorcycle after his tires hit a patch of oil, Michael Cassidy landed on a fire hydrant with such force doctors described it as splitting him up the middle.
The Houston Chronicle reports emergency responders worked heroically to save Cassidy, but by the time Life Flight arrived at Memorial Hermann Hospital in the Texas Medical Center, he was fighting for his life, vital signs fading, both brain and heart starving for more blood. Transfusions couldn’t keep up with the loss.
“He was actively bleeding to death,” said Dr. Michelle McNutt, chief of trauma at Memorial Hermann’s Red Duke Trauma Institute.
But McNutt and her team had a new tool available that gave hope for Cassidy—a catheter that opens a balloon in the body’s main artery, temporarily stopping the hemorrhaging that threatens a patient’s life. Doctors describe it as an “internal tourniquet” and call it a game-changer in the field of trauma.
The idea was inspired by the decades-old use of such balloon-tipped catheters in cardiovascular patients and first envisioned for the battlefields of Afghanistan and Iraq, where soldiers still routinely die from internal bleeding when the injury is to the abdomen and pelvis.
Two military doctors with backgrounds in vascular surgery figured the technology that worked in heart patients could work in combat too and fashioned the first balloon-tipped catheter for soldiers with injuries lower in the body.
Memorial Hermann is leading the effort to bring internal tourniquets to civilian trauma patients. Its doctors published the first case studies employing the technique, using catheters designed for heart patients instead of waiting for the internal tourniquet in development. They learned the technique from Dr. Todd Rasmussen, one of the visionary doctors in the Middle East, then back at Lackland Air Force base in San Antonio.
Rasmussen’s idea didn’t actually make it to the battlefield until 2016, after the device was approved by the Food and Drug Administration. It’s manufactured by PryTime Medical, a San Antonio company that refined the military prototype, initially as a philanthropic venture, then a commercial one. Prytime worked with Rasmussen and Dr. Jonathan Eliason, the other military surgeon.
“No one else would listen to (the military doctors),” says David Spencer, a biotech executive who founded the company. “I did not see a market beyond the military initially either, but the more I got into it, the more I saw there was ‘a there there.’ “
Today, he says, PryTime’s ER-REBOA (the Eliason-Rasmussen Resuscitative Endovascular Balloon Occlusion of the Aorta) device is being employed in 200 U.S. trauma centers. Many of the surgeons now using it were trained by Memorial Hermann doctors.
Cassidy was an ideal patient for the device because his source of bleeding was only his pelvis, not his chest or abdomen. From the groin, McNutt threaded the catheter through the primary artery in Cassidy’s thigh up to the aorta, then opened the balloon in the pelvis region. With the hemorrhaging blocked, Cassidy’s systolic blood pressure rose from an almost lifeless 60 to a normal 140 and his heart rate slowed from 150 to 120.
In the half-hour window before blood flow had to be restored, McNutt’s team stopped the bleeding and prevented infection, a concept known as “damage control surgery.” They then removed the catheter, “able to live to fight another day,” in McNutt’s words.
Cassidy’s complex combination of injuries—his pelvis was fractured and his colon and bladder also were injured— required multiple subsequent reconstructive operations. But in 30 days he was discharged from the hospital.
Without the internal tourniquet, Cassidy would surely have died, says McNutt. Nine months later, the only vestige of the injury is a limp.
Such internal bleeding is one of the great killers of trauma patients. Despite improvements in such care in recent years, the death rate for patients with excessive bleeding in the torso, chest or pelvis remains about 50 percent, according to Rasmussen. Until the advent of the internal tourniquet, doctors’ only recourse had been the thoracotomy, which involves cracking open the chest and whose results are typically poor.
“Such a minimally invasive way to control hemmorrhage is remarkable,” says Dr. Laura Moore, medical director of the Red Duke Institute’s Shock Trauma ICU and a professor of surgery at the McGovern Medical School at UTHealth . “There hasn’t been a lot of technical advancement in trauma resuscitation in the last 20 years - I think REBOA is going to be the defining achievement.”
Still, the device is the early stages of research. Moore says researchers are trying to determine the best patient populations, including whether it can revive patients dead for a few minutes by the time they reach the ER.
Memorial Hermann is leading a multi-institutional trial whose results with a variety of patients will be compared with similar patients treated at centers not yet deploying the device.
Expectations are still measured, mostly because hemorrhaging patients likely to benefit from the device typically have multiple other problems that can result in death. McNutt says the majority of deaths among patients on whom the internal tourniquet is used occur because of brain trauma, often only discovered after the device stopped the patient’s internal bleeding.
Memorial Hermann has employed the tourniquet on roughly 100 patients, whose outcomes depended on the severity of their injury, not the device. Trauma center leaders said in such cases the device’s value was that it bought time.
One Memorial Hermann-University of Maryland Trauma Center study, for instance, showed doctors were able to restore spontaneous circulation, blood pressure and a pulse in 60 percent of patients who arrived at the hospital in cardiac arrest, CPR already in progress.
The odds were certainly against Cassidy making it that far. He survived not just because of the REBOA device, but also because two nurses were in a car behind him when his motorcycle lost control and quickly came to his aid; because recent innovations on Life Flight, such as an in-air blood transfusion, kept him alive during the trip; and because a Memorial Hermann team was ready even before he got there.
“It’s funny, I was real calm after the accident, sure everything was going to be OK,” says Cassidy, 26, a Cypress door assembler who recently became a father. “I didn’t realize how bad it was until after the surgery. I’m very fortunate to be alive.”