Her family posted a GoFundMe and wrote that they're hoping for "a miracle."

A 22-year-old woman who attended the Astroworld Festival in Houston on Friday where Travis Scott performed has been declared brain dead after being injured in a crowd surge that has so far killed eight people.

Bharti Shahani, a senior at Texas A&M University, has been in critical condition and on a ventilator. Her family confirmed with ABC 13 Houston that they were told Shahani was brain dead, and they're meeting to try to figure out what to do next.

Shahani went to the concert with her sister Namrata Shahani and cousin Mohit Bellani, but they lost each other in the rush of the crowd while Scott was on the stage. "Once one person fell, people started toppling like dominos," Bellani told the news outlet. "It was like a sinkhole. People were falling on top of each other. There were like layers of bodies on the ground, like two people thick. We were fighting to come up to the top and breathe to stay alive."

Women-Left-Brain-Dead-at-Travis-Scott-Concert-Here's-What-That-Means-GettyImages-1351614222-1127952415
Credit: Getty Images

Namrata said she and Bellani held onto Shahani's hand, but they were eventually separated in the chaos. "Once we let go of her hand, the next time we saw her, we were in the ER," she said.

Doctors told the family that Shahani had suffered several heart attacks. "She lost oxygen for 10 minutes one time and seven minutes at another time," Bellani said. "So her brain stem was swollen to like 90 percent almost."

Shahani's father, Sunny Shahani, said doctors have told him that his daughter's odds of surviving "are nothing." He added. "We keep saying we'll pray. I request all of Houston to pray for her. Maybe the prayers might work as a miracle for her."

The family has started a GoFundMe to try to cover Shahani's medical expenses. "Bharti is the light of our lives and we are all praying for her full and speedy recovery," Namrata wrote in the GoFundMe.

Shahani's story raises questions about what, exactly, it means to be brain dead. Here's what you need to know.

What does it mean to be brain dead?

"It's complicated," Lewis Nelson, MD, the chair of emergency medicine at Rutgers New Jersey Medical School, tells Health. There are two major parts of the brain, he explains: The cortex, which is the part that helps you think, and the brain stem, which controls things like your breathing.

When someone is brain dead, "both your cortex and brain stem have deactivated—they're not functional," Dr. Nelson says.

A person's heart will continue to beat when they're brain dead and receiving medical care—provided they're put on a ventilator to restore their breathing, which is what typically happens, Dr. Nelson says. "But if someone is brain dead and you turn off the ventilator, they will die," he says.

How do doctors know someone is brain dead?

Doctors will put a patient through a number of tests to determine if they're brain dead, George Teitelbaum, MD, interventional neuroradiologist and director of the Pacific Stroke and Aneurysm Center at Providence Saint John's Health Center in Santa Monica, California, tells Health. One is by measuring electrical activity of the brain. "When someone has basically flatlined activity, they're considered to be brain dead," he says.

Doctors will also typically do tests to determine if there is any blood flow to the brain, along with several physical exams. "When you move the head from side to side, normally the eyes—with a little delay—will track the direction that you turn the head," Dr. Teitelbaum says. "When they just sort of follow the head, it's called doll's eyes." Doctors may also touch the surface of the eyeball and the back of the throat, which would normally cause some kind of physical reaction, he says.

"If someone is not on medication like barbiturates, these tests are highly suggestive of somebody being brain dead," Dr. Teitelbaum says.

How is being brain dead different from being in a vegetative state?

A vegetative state, which is also referred to as a coma, is a deep state of unconsciousness, according to the Cleveland Clinic. When a person is in a vegetative state, they're alive but unable to move or respond to their environment.

This can happen as a complication of an underlying illness or after an injury, like head trauma. People in a vegetative state have lost their ability to think, speak, respond to commands, and be aware of their surroundings, but their brains continue to control things like breathing and sleep patterns.

"You have enough function in your cortex to open your eyes and look around, but you're not aware of what's going on," Dr. Nelson says. "There's a spectrum in this state, and some people look alive to the point where it's hard to convince family members that their loved one isn't going to wake up and become normal."

Nelson points out that there have been stories of people waking up after years of being in a vegetative state. But, he adds, "these are as rare as rare can be and they're so anecdotal that it's hard to know the truth."

Can someone recover from being brain dead?

Unfortunately, no. "Brain death is an irreversible process," Yousef Hannawi, MD, medical director of the Neurosciences Critical Care Unit and an assistant professor of neurology at The Ohio State University Wexner Medical Center, tells Health. "When the patient meets brain death criteria, they are formally declared dead."

Dr. Nelson agrees. "By definition, being brain dead is something that you can't recover from," he says.

Once a person is declared brain dead, families have a hard decision to make: whether to continue to keep their loved one on a ventilator or turn it off. "Sometimes it winds up in court because families and hospitals disagree," Dr. Nelson says. "Someone can lay in a hospital bed for years and a family will not want to turn off the ventilator. But, he stresses, "brain death is absolutely unrecoverable."

To get our top stories delivered to your inbox, sign up for the Healthy Living newsletter