After head trauma, heart attack or stroke, brain cells can continue dying for weeks. UC researchers have a possible prevention plan
After a head injury, stroke, or cardiac arrest, brain cells can die for weeks. This is from damaging seizure-like electrical waves that can spread through the brain and prevent it from communicating.
What's happening in the brain?
Under normal circumstances, crackling sounds deep inside the brain signal communication among an estimated 100 billion neurons. But after a traumatic health event like a brain injury or a heart attack, the brain goes silent. If the patient isn't revived, a massive wave of electrochemical energy is released that gradually poisons the nerve cells.
University of Cincinnati researchers now have a possible prevention plan.
Monitoring and medication is the plan
A "first-of-its-kind" trial is underway, using a three-pronged approach for brain trauma patients who already need surgery.
For patients enrolled, doctors will not only monitor for seizures with an implanted electrode strip but now look for spreading depolarizations (SD). Spreading depolarizations are more commonly called "brain tsunamis." They occur in waves, killing brain cells.
Principal Investigator Jed Hartings, Ph.D., explains that just like a battery, brain cells send electrical signals to each other. But during a brain tsunami they are unable to send them, "interrupting every aspect of brain function. I sometimes explain that the brain cells become a swollen sack of saline; just a big bag of saltwater that's not functional anymore," says Hartings.
In this trial, Hartings, Neurosurgical Director Laura Ngwenya, MD, Ph.D. and the rest of the team will closely monitor blood pressure, blood sugar and body temperature measurements, associated with a higher risk of SD. The second treatment involves a low dose of the drug ketamine and the third method is a higher dose of ketamine.
WVXU has been reporting on brain tsunamis for nearly 10 years. Hartings says brain tsunamis are reversible, but with every second and minute that passes, more permanent damage is done. He says this seems to be a universal principle that applies to anyone with or without a brain injury.
"Imagine transferring this knowledge to a patient with cardiac arrest where there is a severe cessation of blood flow to the brain and you want to revive him," he says.
It's unclear how long brain tsunamis continue in a patient, possibly up to a month. "There's strong emerging evidence that they would occur even in something as mild as a concussion," Hartings says.
Dr. Ngwenya says this is one of the first trials to attempt to do personalized medicine in traumatic brain injury patients. "There has been a lot of work that had been done in the past where there had been a lot of failed clinical trials. And some of that was because we were just treating all patients with the same drug and it wasn't working. One of the key things about this study is that we're able to identify the patients that are having spreading depolarizations and then target the treatment to that patient."
How much a brain tsunami affects brain cells depends on the patient. The brain can recover in otherwise healthy people with no underlying injuries, like migraine aura suffers. But ultimately, Hartings says eventually we will all experience one.
"We all experience spreading depolarization, at least once at the end of life because it's the terminal wave that passes through the brain that triggers the onset of the cell death process in brain tissue," he explains.
This medical trial is the first step to stop brain tsunamis before people reach end of life.