First lady Michelle Obama shakes hands with Dr. James Denton, a first responder to the Aurora theater shooting, at The Medical Center of Aurora on Saturday Aug. 11, 2012, in Aurora, Colo.  (AP Photo/Jack Dempsey)

AURORA | First Lady Michelle Obama on Saturday made a surprise visit to the hospital that treated victims of last month’s movie theater shooting.

Obama arrived about 3:30 p.m. in a conference room off the Medical Center of Aurora’s cafeteria, where several dozen members of the facility’s emergency, operating and intensive care unit staffs lined up to speak with her.

After chatting with staff, Obama visited with victims of the shooting and their family members — including one patient who remains in the hospital’s ICU, more than three weeks after the shooting.

James Holmes, 24, is accused of killing 12 people and wounding 58 at a midnight screening of “The Dark Knight Rises.” The multiplex where the attack occurred is about 2.5 miles from the hospital, which treated 18 people in the hours after the assault.

Reporters were allowed to watch Obama talk to some of the hospital staff, but her comments were not audible. She wore grey slacks and a pink cardigan as she shook hands and hugged the medical workers and physicians.

Justin Mast, an emergency room nurse who was one of the people who greeted the first lady, said she quickly won over the room.

“It’s always nice when they take time out of their schedule and help thank people,” Mast said. “She was very pleasant and personable. It felt like everybody in the room was able to connect with her.”

He added that it was clear that Obama had worked in a hospital before, because she asked whether anyone had been up all night working. Obama was once a vice president at the University of Chicago Medical Center.

After the roughly 75-minute visit, the first lady headed to a fundraiser for her husband’s re-election campaign in Denver.