Damar Hamlin Showing 'Signs Of Improvement', Buffalo Bills Say

Buffalo Bills safety Damar Hamlin is showing "signs of improvement," the team said Wednesday, but the player remains in critical condition two days after suffering cardiac arrest during a game against the Bengals in Cincinnati.

In a tweet, the team said the 24-year-old safety "is expected to remain under intensive care as his health care team continues to monitor and treat him."

Hamlin's uncle, Dorian Glenn, said Tuesday night that his nephew has lung damage and can't breathe on his own after he collapsed on the field Monday night. He had been receiving 100% oxygen from a ventilator but that is now down to 50%, Glenn said.

Glenn also said Hamlin's heart stopped twice — once on the field when they resuscitated him and again at the hospital, "and they had to hit him with the defibrillator."

"People who don't even know us are showing love and support and we're so thankful for that," Glenn said. "I know those prayers are helping because he's definitely recovering ... God got a mission for him and that's why he's still here."

On a Wednesday conference call, the NFL's chief medical officer, Dr. Allen Sills, praised the teams' medical staffs for their quick response during the game. 

"It's certainly not an exaggeration to say that the skilled and immediate response by these talented caregivers prevented a tragic outcome," Sills said. 

While it's not yet clear exactly what Hamlin experienced, CBS News medical contributor Dr. David Agus said Hamlin may have suffered what's known as commotio cordis, which is heart arrhythmia that occurs when someone takes a direct hit to their chest.

Agus said only about 30 cases of commotio cordis occur in the U.S. every year, including among Little League players who get hit in the chest with a ball.  

Describing the condition as "a confusion of the heart," where the heart muscle pumps erratically, Agus said the energy of the blow interferes with the electrical signals in the heart, creating a ventricular fibrillation — a fast, erratic heartbeat that does not pump blood into the brain. When that happens, Agus said the heart needs to be shocked back into regular rhythm.

"That's why there are defibrillators on the sidelines of games, is to be able to use them to shock the best heart back into a regular rhythm," he said.

Fans and members of the Bills community gathered outside Highmark Stadium for a vigil on Tuesday to pray for Hamlin. 

Just 32 miles away from Highmark Stadium, Niagara Falls was lit up in red in honor of Hamlin. Residents in Western New York also purchased blue and red lightbulbs to put outside of their homes in show of support.

The sports world has also come together and united around Hamlin. 

All 32 NFL teams changed their Twitter profile pictures to an image of Hamlin's No. 3 jersey along with the words, "Pray For Damar." 

Shortly after Hamlin collapsed, the NFL suspended the "Monday Night Football" game between the Bengals and Bills. In a statement Tuesday, the NFL said the game will not be resumed this week, and no reschedule date is known at this time.