|Benjamin Abella, A.B. ’92, who received an M.D. from Johns Hopkins University, is an assistant professor of emergency medicine at the University of Pennsylvania and directs clinical research at Penn’s Center for Resuscitation Science. (Photo by Miles Kennedy)
At the Heart of the Matter
At the University of Pennsylvania’s Center for Resuscitation Science, Benjamin Abella researches using hypothermia to increase the survival rate of cardiac arrest victims.
As a young internal medicine resident at the University of Chicago Hospitals, Benjamin S. Abella found the experience of treating cardiac arrest patients filled with drama and disappointment. “Survival after cardiac arrest is very poor,” Abella, A.B. ’92, observes. “What made a big impression on me was that here we are in the very center of American critical care, yet we can’t save a lot of these patients whose hearts stop suddenly.”
Indeed, 300,000 Americans die each year of cardiac arrest, the leading cause of death nationally. The survival rate is around 10 percent. “So despite the television shows that would lead you to believe that many people are heroically saved,” Abella says, “in fact, only 1 in 10 patients survives to leave the hospital. Yet those who do survive can go back to productive, active lives, and that’s really what motivates me. And it makes me ask: ‘Why can’t we save more people?’”
Abella focuses on this question, working hard to change the odds. After completing a genetics degree at Cambridge University and medical training at Johns Hopkins University, he joined the University of Chicago in 1998. In 2006, Abella moved to the University of Pennsylvania, where he is assistant professor of emergency medicine and directs clinical research at the new Center for Resuscitation Science.
Changing the odds, for Abella, has involved work on two principal research tracks—pioneering investigations into the effectiveness and enhancement of cardio-pulmonary resuscitation (CPR), and advancing the understanding of therapeutic hypothermia, which lowers body temperature to about 90 degrees Fahrenheit for 12 to 24 hours.
Though chilling the body down might seem an unlikely way to save it, this counter-intuitive method is increasingly used in Europe and the United States, with convincing results. “Hypothermia is a very exciting area of research and medical care,” Abella notes. “It’s probably the most important new intervention for the care of cardiac arrest victims to come about in the last 50 years, since the invention of CPR and defibrillation. It’s just that impressive. It can almost double the chances of survival and brain recovery in many cases.”
“Hypothermia is a very exciting area of research and medical care,” Abella notes. “It’s probably the most important new intervention for the care of cardiac arrest victims to come about in the last 50 years, since the invention of CPR and defibrillation.”
A major risk for resuscitated cardiac arrest victims is what’s called reperfusion injury, caused when blood flow resumes uncontrolled. “You would think that blood flow is good,” Abella observes, “but if blood flow is returned rapidly after a period of no flow, it can trigger a number of damaging processes. The mitochondria become dysfunctional; you also can see massive inflammation throughout the body. This can lead to brain injury.” Indeed, reperfusion injury is extremely dangerous and significantly increases the odds against survival.
Hypothermia mitigates reperfusion injury. “If you can get the body through this aberrant activity that occurs for 12 to 24 hours after reperfusion, things begin to settle down,” Abella explains. “So if you cool somebody for 24 hours, it helps the patient weather this reperfusion injury cascade such that they have better brain survival and better survival overall.”
Therapeutic hypothermia cools the body to 32 to 34 degrees Celsius by means of cooling pads and/or catheters into the bloodstream. “We’ve worked with a number of companies to develop cooling technologies,” Abella says. “And we’re developing new approaches to cool people faster, because we believe quicker is more effective.”
In fact, he adds, his research seems to indicate that cooling during cardiac arrest itself might be the most effective approach of all. “You may be able to get on top of the reperfusion injury as it develops,” he muses. Thus another line of research focuses on cooling in ambulances. “There are a lot of technical hurdles,” Abella says, “but pre-hospital cooling may be an important direction.”
Therapeutic hypothermia essentially puts into practice a long-observed phenomenon. In ancient Greece, Hippocrates wrote of packing wounded soldiers in snow. One of Napoleon’s surgeons observed that injured soldiers who were kept cold had higher survival rates than those kept close to the fire and given warm cognac. Media today occasionally carry astonishing stories of people surviving long intervals in icy water. Abella himself appeared in an ABC News feature about a man who survived an hour under water in a frozen Iowa lake.
“We don’t completely know how it works,” Abella acknowledges. “There are a number of ways it may work: It seems to slow metabolism, lessening the inflammatory response and brain swelling. It seems to improve function of mitochondria”—the energy powerhouses in cells, which can become wildly dysfunctional during reperfusion and release toxic compounds signaling cells to die.
These seeming mysteries have slowed hypothermia’s adoption in the United States. “It makes people nervous,” Abella admits. “We’re actively involved in research to understand the basic science of hypothermia.” He and his colleagues also are working to spread awareness about it and conducting research to refine the cooling process.
|Some 300,000 Americans die each year of cardiac arrest, the leading cause of death nationally. The survival rate is around 10 percent. Those who do survive require comprehensive evaluation and care, including imaging. (Photo by Miles Kennedy)
How CPR works, on the other hand, is no mystery, but Abella discovered that administering it successfully remains a challenge. His first venture in resuscitation research probed a previously unexamined issue: How well do certified people perform this vital function? He worked with a manufacturer to develop CPR sensing technology to measure both chest compression and ventilation. “We could literally record, almost like a flight data recorder, everything that was done during resuscitation,” he explains. “We found, much to our dismay, that CPR performance was poor.” In high-stress conditions, both CPR-trained laypeople and medical personnel typically fail to compress the chest deeply or rapidly enough. These failures are another major factor in the long odds against cardiac arrest survival.
Thus Abella has worked to improve CPR training, particularly in developing equipment to simulate high-stress conditions during training, and to provide feedback about compression and ventilation to those performing CPR, signaling them to adjust if necessary. “It’s not that health-care professionals and bystanders don’t want to do the right thing,” Abella notes. “It’s just that it’s asking a lot of us humans to perform a highly technical task in a crisis mode.”
Abella also wants to encourage many more laypeople to take CPR training. “Over two-thirds of patients who suddenly collapse of cardiac arrest receive no bystander CPR,” he says. Because paramedic arrival can take five or six minutes or more, and survival drops by 10 to 15 percent per minute, training many more people in CPR offers hope of markedly changing those 9-to-1 odds.
Abella worked with the American Heart Association to develop a kit with which laypeople can teach themselves CPR. He has several students supervising community training programs. He works with community leaders to expand CPR training opportunities. Why not offer training in driver’s license facilities, he wonders, where people often sit for a couple of hours with nothing to do? Why not make CPR training a requirement for high school graduation?
“CPR is a very low-cost intervention that can dramatically save lives,” he says.
Saving lives after cardiac arrest has been Abella’s consistent focus since his residency. For those unlucky victims whose hearts simply stop beating without warning, his efforts to enhance CPR and expand the use of therapeutic hypothermia hold promise of changing today’s long odds against survival.