Jan. 3, 2023 --- What can happen if your brain loses oxygen for an extended period?
During Monday night's Buffalo Bills vs. Cincinnati Bengals game, NFL fans watched nervously as Bills safety Damar Hamlin lay flat on his back surrounded by medical personnel, teammates, and coaching staff.
Hamlin, 24, had just tackled a Bengals receiver late in the opening quarter when he stood up and immediately collapsed.
The Buffalo Bills, in a statement, said Hamlin had experienced cardiac arrest on the field and is sedated and in critical condition at the University of Cincinnati Medical Center.
Cardiac arrest is when there is an electrical malfunction to the heart -- which can create an irregular heartbeat -- and the heart's pumping function is compromised, according to Laxmi Mehta, MD, director of preventive cardiology and women's cardiovascular health at the Ohio State University Wexner Medical Center. When this happens, there is not effective pumping of blood to organs, including the brain and lungs, and severe damage can occur.
Hamlin had his heartbeat restored on the field after nearly 10 minutes of CPR and oxygen via an AED machine, also known as a defibrillator, a medical device that delivers an electrical shock to help the heart return to normal rhythm.
Commotio cordis -- or a chest blow that disrupts your normal heart rhythm -- is one possible explanation for why Hamlin experienced sudden cardiac arrest. This type of injury is rare in football. It's much more common in youth baseball, says Grant R. Simons, MD, cardiac electrophysiologist at Hackensack University Medical Center in New Jersey.
Simons says that the way Hamlin fell on his back proves the severity of the injury.
“When people just fall backwards like that --- and they don't put out their arms to try to break the fall or do anything defensive -- it's usually a sign that they've lost consciousness,” Simons says.
“When someone loses consciousness, the immediate first thought [is], 'Well are they just unconscious or are they experiencing sudden death?' What I saw was someone who I was concerned had experienced sudden death.”
Since crucial information about Hamlin's condition has yet to be released publicly, certain widely circulated details of Hamlin's injuries can still be deemed “speculation,” Mehta says. Therefore, while Hamlin may have received CPR and oxygen assistance for several minutes, we can't be certain “the extent of damage to his brain and other organs due to the lack of adequate oxygen.”
The point of doing chest compressions during CPR is to mimic how the heart pumps. “So, we would assume he had adequate circulation of blood flow to the brain,” Mehta says. “But if people don't get CPR done in a timely fashion, or if they don't get effective chest compressions, then yes, there can be a lack of adequate blood flow, lack of oxygen, and can cause some brain damage.”
This phenomenon, called anoxic brain injury, can result in stroke-like effects, including seizures, the inability to move certain body parts, slurred speech, and trouble forming sentences. We need to learn more about just how quickly and successfully Hamlin received chest compressions to better understand his risk for these types of brain injuries. If someone gets prompt, good compressions, and a prompt shock, then the survival rate of this injury is very high, says Simons.
“If the compressions weren't good and they didn't get proper blood flow to his brain during the time that they had to go retrieve the defibrillator, you worry about the neurologic damage to his brain. Generally, when they get those two things done promptly, most patients have a full recovery neurologically in terms of their cardiac function.”