When Buffalo Bills safety Damar Hamlin collapsed Monday night after a horrifying on-field cardiac arrest, he did it in one of the most medically favorable environments outside of a hospital.
And unlike many of the 350,000 people who suffer out-of-hospital cardiac arrests in the United States each year, the 24-year-old had the advantage of youth and the conditioning of a professional athlete.
All of that matters. But Hamlin’s prospects ultimately may depend more on how long it took to restart his heart and how effectively CPR kept his organs — especially his brain — supplied with blood and the oxygen it carries, critical care and cardiology experts said Tuesday. Little is publicly known about either.
“When someone is having a sudden cardiac arrest emergency for any reason ... time is absolutely critical,” said Matthew Levy, an associate professor of emergency medicine at Johns Hopkins University School of Medicine. “For every minute that someone is in sudden cardiac arrest — every minute where their heart is not beating normally and their body tissue is not getting the oxygen it needs — their survival goes down by like 7 to 10 percent. So time is absolutely of the essence.”
“The key in any cardiac arrest is how quickly and effectively CPR is done,” said Aaron Baggish, a Mass General Brigham sports medicine cardiologist and founder of the Cardiovascular Performance Program at Massachusetts General Hospital. “So it has to start soon, and it has to be done well enough to get blood to the brain and the other vital organs for as long as it takes to start the heart again with defibrillation.”
Hamlin collapsed in the first quarter of the Bills’ much-anticipated “Monday Night Football” game against the Cincinnati Bengals, to the shock of millions watching on television. A leading theory among experts is that Hamlin suffered ventricular fibrillation from the blow to his chest, which caused his heart to pump in a disorganized fashion, disrupting blood flow to the rest of his body.
Emergency personnel rushed to aid him, and stunned players on the field, some in tears, encircled the fallen player, obscuring the resuscitation efforts, which lasted about 15 minutes before Hamlin was taken away in an ambulance.
Since then, the Bills and other authorities have said Hamlin suffered cardiac arrest and that his heart was restarted before he left the field. He is sedated, with a breathing tube in his trachea, in an intensive care unit at University of Cincinnati Medical Center.
That leaves experts guessing at his prospects from what they could see, research and the interventions used to revive him. All stressed that their remarks were merely informed speculation.
“I’m cautiously optimistic just knowing that his heart was revived and ... it was revived before he got in the ambulance,” said John Elefteriades, a professor of cardiothoracic surgery at Yale School of Medicine.
Restarting Hamlin’s heart is critical, Elefteriades said, because even the best-performed external CPR cannot pump blood as effectively as the heart. The main worry in cardiac arrest is damage to the brain from a lack of oxygen that could kill Hamlin or leave him with severe neurological deficits akin to the impact of a stroke, Elefteriades said.
Even 15 minutes of CPR is within the range associated with positive outcomes for some people, according to a 2016 study by Japanese researchers published in the Journal of the American Heart Association. For people whose cardiac arrest responds to defibrillation, such as Hamlin, CPR of less than 30 minutes was an important factor in one-month survival, and CPR of less than 20 minutes was associated with better one-month survival with favorable neurological outcomes.
The speed at which CPR was started is another factor that benefits Hamlin, said Anne Curtis, an expert in cardiac electrophysiology at the University at Buffalo who was watching the game at home when Hamlin collapsed.
“What we say in medicine is you’ve got four minutes,” she said. “If you can start effective CPR within four minutes of a patient going down, you can have a very good neurological outcome.”
In retrospect, it may seem obvious to begin CPR and call for a defibrillator immediately when cardiac arrest is suspected, said Connor O’Brien, associate director of critical care cardiology at the University of California San Francisco. But medical personnel racing to a fallen football player are first considering head, neck and spinal injuries, followed by orthopedic concerns, he said. A player may be groaning or semiconscious, so cardiac arrest may not be apparent.
It also may take time to get a good feel for the player’s pulse beneath his uniform. His jersey and shoulder pads must be removed to use the defibrillator paddles. The player may need to be shocked more than once, and even after his heart is restarted, normal rhythm can be disrupted again, depending on the severity of the injury and diminished blood flow, O’Brien said.
“Your heart likes a normal milieu. It likes that you be in homeostasis,” he said.
All in all, Baggish credited medical personnel on the field with doing an excellent job.
“What those of us watching the game on national TV saw was an example of a very effective response,” said Baggish, who has worked with the New England Patriots, among other professional teams. “There was prompt recognition of a problem, and the medical team was out on the field doing their work literally within minutes to seconds. And that’s what we hope for.”
Little is known about Hamlin’s first 24 hours of care, but the experts said doctors probably cooled his body several degrees with various devices, a technique many consider valuable after cardiac arrest but is still debated in the medical community. They are watching his blood pressure and respiration carefully and almost certainly have conducted a variety of tests and scans in an effort to determine damage to his brain, O’Brien said.
After 24 hours, they may try to wake him if he does not show signs of awakening on his own, in an effort to further assess whether he has suffered deficits, he said.
The release of scant information so far is not significant, Curtis said. Doctors are “giving the brain a rest while he recovers from this event,” she said.