OAKLAND — Discussing the events of the past week, Sandra Chatman said it “felt like somebody stabbed me in the heart.”

Her granddaughter, 13-year-old Jahi McMath, has been declared brain-dead, just days after undergoing surgery to have her tonsils removed.

“They took away my granddaughter. That’s how it feels,” said Chatman.

Jahi’s family, including her mother, Nailah Winkfield, huddled by her side at Children’s Hospital Oakland for a sixth day Sunday, calling on the community for prayers and searching for answers on what went wrong during what was supposed to be a one-night stay for the family favorite.

Jahi arrived at the hospital Monday and was supposed to be released Tuesday, the family said.

Monday night, Chatman, a veteran nurse at Kaiser Permanente in Oakland, noticed her granddaughter was bleeding from her mouth and nose. She later went into cardiac arrest.

Jahi spent Tuesday on a ventilator. By 2 a.m. Wednesday, doctors said she had swelling in her brain, and Thursday, she was declared legally brain-dead, family members said.

The hospital staff is reviewing what happened, as they do when any procedure does not have the anticipated results, said spokeswoman Melinda Krigel.

Jahi’s uncle, 27-year-old Omari Sealey, said the hospital should have done more to stop the bleeding.

“There was a lack of urgency,” Sealey said. “It’s shock, it’s disbelief. You never think something like this will happen to you.”

Family members describe Jahi as a well-behaved, bubbly teen who has been looking forward to spending the holidays with family and attending an eighth-grade dinner dance at E.C. Reems Academy of Technology and Arts.

Jahi’s family has asked the hospital keep her on life support for as long as possible, even if it means spending Christmas at the hospital.

“As long as she has a pulse, we want her on life support,” Sealey said. “We want her to come home for Christmas. We want to give her presents. We want a chance for a Christmas miracle.”

Krigel, the hospital spokeswoman, said “the hospital is very, very sad about this outcome.”

“It’s incredibly sad,” Krigel said. “What I can add is that there is informed consent that comes with any surgery and that with any surgery, there can be unanticipated outcomes.”

Before her surgery, Jahi took off her pearl earrings and gave them to Chatman. She asked Chatman to put them back on her as soon as she woke up from surgery. The pearls are now tucked inside Chatman’s purse, where they will stay.

“It’s so hard to look at them. I get choked up,” Chatman said. “I’ll keep them for a lifetime. In every purse I carry. They will always be with me.”

Contact David DeBolt at 510-262-2728, and at Twitter.com/daviddebolt. Contact Rick Hurd at 925-945-4789 and at Twitter.com/3rdERH.