A 13-year-old girl has been declared brain-dead after going into hospital to have her tonsils removed.
Jahi McMath had the routine surgery on Monday but suffered complications during her recovery.
Her mum Nailah Winkfield and grandmother Sandra Chatman said hospital staff had failed to provide adequate care and attention to the teenager.
Nailah took her daughter to at Oakland Children's Hospital, California, to have her tonsils and adenoids removed because she suffered from sleep apnoea. She said Jahi was nervous but she assured her daughter she would feel better after the operation.
Jahi had the procedure but while she was recovering she started to bleed from her nose and mouth.
Her mum told ABC 7: "My daughter had actual clots sliding out of her mouth and they gave me a cup and said, 'Here, catch them with the cup so we can measure them'."
Grandmother Sandra said nursing staff did not react until she began screaming for help.
She said: "I was the last one to see Jahi. I said, 'Somebody help my baby please!' And they came in and starting working on her. The next thing I know, the doctor said, 'Oh no, she doesn't have a heart rate anymore'."
Jahi went into cardiac arrest and was resuscitated. She spent Tuesday on a ventilator, but by 2am on Wednesday doctors said she had swelling in her brain. The next day, she was declared legally brain-dead.
Jahi is now on life support as her family tries to come to terms with what has happened.
A spokesperson for Oakland Children's Hospital said in a statement: "We're very sad about this outcome, about what's happened to her, but at this point I have no information on the details of the surgery.
"We will certainly investigate what happened. In any surgery there are risks and there can be unexpected, unanticipated complications."
The family has no plans to remove Jahi from life support and Sandra said that as long as her heart is beating, they will keep her in the hospital, even if it means spending Christmas in there.
She said: "As long as she has a pulse, we want her on life support. We want her to come home for Christmas. We want to give her presents. We want a chance for a Christmas miracle."
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